UAV (Unmanned Aircraft Vehicle) has revolutionized the creation of orthophotos with its contribution to increased safety, lower costs and more effective ways when making orthophotos. The traditional aerial photogrammetry with airplanes and placement of flight signals has been the standard method for years. To fly with UAV instead of an airplane is cheaper and saves time, however, the placement and measurements of flight signals is still time consuming and therefore expensive. The company DJI has developed a new UAV called Phantom 4 RTK that supports satellite based technology for direct georeferercing.

This study compared two different measuring methods when producing orthophotos with UAV: direct georeferencing with NRTK (Network Real Time Kinematic) and indirect georeferencing when using different number of Ground Control Points (GCP). The study was conducted at the University of Gävle over an area of eight hectares. An investigation of the deviation in plane and height resulted in acceptable units based on the guidelines that were followed in HMK – Ortofoto and the controls that were followed from SIS- TS 21144:2016.

The RMS value in plane for the indirect georeferencing method is 0,0102 m. For the direct georeferencing method the RMS value in plane when using ground control points is between 0,0132 and 0,0148 m. At last the RMS value for the direct georeferencing method without ground control points is 0,0136m. The RMS value in height is between the intervals 0,008-0,025 m.

The data presented in this study show that an accepted quality in the orthophotos can be acquired based on the RMS values in plane and height for every georeferencing that was tested. After accomplished controls and evaluation the results show that the different georeferencing methods doesn´t differantiate too much from each other based on their quality. However, the direct georeferencing method with ground control points is more effective from a time perspective.

Phantom 4 RTK is new on the market and more research is necessary in order to understand the potential of this technology and its posibility to integrate into society. More research is recquired for the direct georeferencing method in order to evaluate the quality of orthophotos.

Public transport plays an important role in sustainable urban development. Increased use of public transport and walking contributes to improving the climate by reducing greenhouse gas emissions. To increase the number of people choosing to walk to public transport, the accessibility and quality of bus stops need to be improved. Factors such as safety, security, attractiveness and accessibility can be used to encourage more people to walk to public transport. More transport options help individuals from different income groups and communities to have greater access to more destinations. Not all income groups have the same need for public transportation. For example, high-income earners are not as dependent on public transport as low-income earners.    The aim for the study is to increase knowledge on whether there is a relationship between neighborhood income levels, accessibility and quality of bus stops. The methods used to conduct the study included a network analysis that includes population, building as well as income estimation. Furthermore, a field observation was conducted in the study areas Husby and Trångsund, along with a survey and a Chi2-test. The study found a significant difference between the quality and accessibility of bus stops based on neighborhood income level. The income level of a neighborhood influences the quality of its bus stops, as confirmed in Husby by a Chi2-test, which demonstrated a statistical correlation. The quality of the bus stops was assessed using a checklist based on scientific literature and general guidelines. Bus stops in Trångsund can be considered of higher quality, as they meet more of the criteria on the checklist compared to Husby. Income levels in the neighborhoods also affect the accessibility of bus stops. In Husby, the annual median income for all income groups is lower than the Swedish average, which mean that residents are more dependent on public transportation. In contrast, the annual median income for high earners in Trångsund is higher than the Swedish average. High income earners are more likely to use private cars which may reduce reliance on public transport. Therefore, accessibility to bus stops may be better in Husby than in Trångsund, based on the results of the population, building and income estimation. 

In the case of infrastructure projects, the authority should inform the nearby residents about what is happening in their area. Research shows that anchoring and trust are created when dialogues are applied in the planning process. These democratic processes are important to satisfy the interests of the public. The social aspect of a sustainable development is strengthened by allowing the public to participate in society's development, which in turn leads to greater equality. Changes create different reactions and communication has a significant role in the link between the public and authority, since information flows can contribute to less irritations and misunderstandings. An authority like the Swedish Traffic Authority not only has to deal with the public when establishing infrastructure projects, but also systems for planning processes, legislation, and financial frameworks. The purpose of this study is to investigate how the Traffic authority goes about giving out information to nearby residents in the planning process of new infrastructure and how the distribution of information affects the nearby residents' acceptance of the infrastructure project.

A case study is carried out over two “2minus1” rural roads in Sundsvall and Timrå municipalities. For methods, questionnaires and interviews are used in studies, with the aim of collecting qualitative and quantitative data. Two methods are used to be able to verify results, as well as to get an overall picture of how the process works when establishing a “2minus1” road. Web-based questionnaires were sent to nearby residents at the two “2minus1” road, several interviews of nearby residents were conducted during site visits, and interviews were conducted with employees at the Swedish Traffic Authority who have expertise in establishing “2minus1” roads.

The results of the interviews with the Swedish Traffic authority showed that there is no elaborate process for how they should distribute information to nearby residents when establishing a “2minus1” roads. This is because the “2minus1” roads are a new type of road and only a few of them have been established in Sweden. The results of the study indicate that information has a great importance for the acceptance of nearby residents. Acceptance is affected by when the information is distributed and whether the content of the information is adapted to the target group. By providing information on how the “2minus1” roads should be used and providing an understanding of the benefits of a “2minus1” roads, it contributes to greater acceptance by residents. Acceptance is a complex subject that can depend on many different factors. Acceptance is not only impact by information, but it can also depend on personal preferences.

Multidecadal sea level variation in the Baltic Sea is investigated from 1900 to 2020 deploying satellite and in situ datasets. As a part of this investigation, nearly 30 years of satellite altimetry data are used to compare with tide gauge data in terms of linear trend. This, in turn, leads to validation of the regional uplift model developed for the Fennoscandia. The role of North Atlantic Oscillation (NAO) in multidecadal variations of the Baltic Sea is also analyzed. Although NAO impacts the Baltic Sea level on seasonal to decadal time scales according to previous studies, it is not a pronounced factor in the multidecadal variations. The acceleration in the sea level rise of the basin is reported as statistically insignificant in recent studies or even decelerating in an investigation of the early 1990s. It is shown that the reason for these results relates to the global warming hiatus in the 1950s−1970s, which can be seen in all eight tide gauges used for this study. To account for the slowdown period, the acceleration in the basin is investigated by fitting linear trends to time spans of six to seven decades, which include the hiatus. These results imply that the sea level rise is accelerated in the Baltic Sea during the period 1900–2020.

The International Association of Geodesy defined the International Height Reference System (IHRS) in 2015. IHRS will be realised through the International Reference Frame (IHRF) primarily by geopotential numbers (or physical heights). On the global scale, a sparse core reference network will be the basis for the realisation. To ensure local access to the frame and the best possible conditions for height datum unification, denser realisations (or densifications) will be needed. The adopted realisations can be either regional, national, or local. According to the published recommendations on regional IHRS realisation, GNSS ellipsoidal heights and a gravimetric (quasi-) geoid model form the basis to compute a pointwise IHRS realisation, but it is possible to supplement this by local levelling to gain local access to the frame and improve the relative uncertainty. The main purpose of this article is to investigate different ways to incorporate levelling observations in the IHRS realisation process and explore potential improvements. The investigation is a case study over Sweden that uses an initial pointwise IHRS realisation and precise levelling observations from the Baltic Levelling Ring (BLR) project. The levelling network is adjusted with respect to the pointwise IHRF geopotential numbers using three different approaches regarding the a priori variance-covariance matrix used for weighting of the observations. The approaches are constrained adjustment, weighted adjustment with realistic a priori uncertainties (variance covariance matrix) and weighted adjustment with Variance Component Estimation (VCE) to iteratively tune the a priori variance-covariance matrix. It is shown that the pointwise IHRS realisation can be improved significantly by the inclusion of levelling observations. Both the estimated standard uncertainty of the adjusted IHRF geopotential numbers as well as the relative standard uncertainty between nodal benchmarks are reduced by approximately 40 percent in the Swedish case. To fully exploit the potential of precise levelling observations in the IHRS realisation process, it is recommended to use some form of weighted adjustment, preferably using VCE to obtain a realistic balance between the initial pointwise and levelling observations.

A common global vertical reference frame for physical heights is essential in many applications, but an equivalent to the three-dimensional International Terrestrial Reference System has until recently been lacking for physical heights. The International Height Reference System, IHRS, was defined in 2015. It will be realised by the International Height Reference Frame, IHRF, on the global level by a sparse core reference network. To ensure local access and enable optimum height datum unification, adopted regional or national realisations (or densifications) are required. This thesis explores regional and national realisations of IHRS, employing both the standard pointwise methodology as well as levelling assisted approaches. Levelling observations have the potential to improve pointwise IHRS realisations. The thesis studies a regional levelling network that is adjusted with respect to an initial pointwise IHRS realisation using different approaches. The evaluation of these solutions is based on the resulting geopotential numbers and their estimated standard uncertainties. It is shown that including levelling observations in the IHRS realisation process might lead to significant improvements. It is recommended to employ a weighted adjustment of pointwise geopotential numbers and levelling observations, and to utilise variance component estimation as a tool to estimate a priori uncertainties. With a comparison to the Swedish levelling based realisation of the European Vertical Reference System, RH 2000, differences in the definitions of reference systems are explored. Corrections related to known effects, such as permanent tide concepts, postglacial land uplift epoch and zero level, are here considered. It is shown that the differences in the obtained geopotential numbers can be explained to rather large extent by these corrections. Finally, the thesis discusses how national and regional realisations of IHRS should be interpreted with respect to the global realisation.

The International Height Reference System (IHRS) was defined by the International Association of Geodesy in 2015. Since then, the international geodetic community has been working on the specification and establishment of its realisation, the International Height Reference Frame (IHRF). This frame will primarily be realised by geopotential numbers (or physical heights) in a sparse global reference network. In Sweden, only one such global station is planned. Regional and national realisations (or densifications) computed in accordance with the IHRS definition are needed to enable the best possible unification of height datums. The main purpose of this article is to make a case study for Sweden regarding the national realisation of IHRS and to investigate in what way preliminary IHRF differs from the current Swedish levelling-based realisation of the European Vertical Reference System, RH 2000. The two different quasigeoid models that we consider best over Sweden at the present time are used to compute the preliminary IHRS realisations in the study. The realisations are compared to each other and to RH 2000. It is shown that a very significant part of the difference to RH 2000 is due to the different postglacial land uplift epochs, permanent tide concepts, and zero levels. The standard deviation for the difference between one of the preliminary national IHRS realisations and RH 2000 is reduced from 75.5 to 19.2 mm after correction of the postglacial land uplift and permanent tide effects. The corresponding mean differences are –208.5 and –454.7 mm, respectively. The magnitude of the mean difference thus increases when the corrections in question are applied.

The International Height Reference System (IHRS) was defined by the International Association of Geodesy (IAG) in 2015. The global International Height Reference Frame (IHRF) should provide access to the IHRS in a broad sense. To provide high accuracy local access, regional (or national) realisations will also be needed. This study aims at evaluating different approaches to compute a denser regional realisation of IHRS in case a high accuracy levelling network is available. Using Sweden as a case study region, a GNSS (Global Navigation Satellite System) and geoid based pointwise realisation is compared with three types of levelling assisted realisations. The latter are made by applying least squares adjustments of the precise levelling observations with fixed potential value(s) from either the global IHRF station in Sweden or the pointwise potentials of a larger number of stations. It is concluded that making a minimum constraint adjustment with one station fixed is not the best option. It is favourable to fix a reasonable number of pointwise stations at an internal distance over which the relative uncertainty of levelling is significantly lower than the relative uncertainty of the pointwise solution. The investigation is made using levelling data from the third precise levelling of Sweden, the NKG2015 quasigeoid model and the NKG2016LU postglacial land uplift model.

A recently introduced GNSS instrument on the market is Leica GS18 T with tilt compensation, based on GNSS/Inertial Navigation Systems (INS) integration, with no need to centre the survey pole with the GNSS instrument over the target point being measured. Besides making surveying faster, the tilt compensation technique enables measuring of hidden points where the use of conventional GNSS measuring normally is not possible without more time-consuming methods. The instrument also has advanced GNSS signal tracking which makes surveying in challenging environments possible.

In this study, the Leica GS18 T has on behalf of Lantmäteriet been tested through studying the measurement uncertainty in network RTK measurement with tilted survey pole in three different situations: with the survey pole tilted in various degrees in both favourable and challenging survey environments; with tilt towards north, east, south and west to test if the tilt direction would affect the result; and for surveying of building corners as a possible field of application. In the latter case, the result was compared with what can be achieved with the conventional hidden point method using intersection of distances. The analysis of the measurement uncertainty was based on calculations of standard uncertainty, RMS (Root Mean Square) and mean deviation.

The measurement uncertainty from the first part of the test was on cm-level horizontally, both in favourable and challenging survey environments, and in height on mm-level in favourable survey environment and on cm-level in challenging survey environment. Further, the results indicate that the tilt direction affects measurement uncertainty. The reason for this is not clarified and needs further investigation. The measurements of building corners resulted in a mean deviation of approximately 12 mm when the survey pole was tilted 30°. The hidden point method using intersection of distances generally resulted in lower mean deviation, even though the difference is relatively small (4 mm at best). To summarize, Leica GS18 T seems to be well suited for measuring with tilt in detailed surveying, at least if the requirements of position uncertainty is on cm-level.

Condominiums are a specific variant of three-dimensional property formation, which are intended to house a residential apartment. The requirement that condominiums must be formed at least three in a cohesive unit, means that facilities such as building frames and facades will be common to several condominiums. These facilities are managed by the owners of the condominiums through a community association. Breviksängar in municipality of Öckerö, was one of the first areas with condominiums in Sweden, and in addition, it consists of privately owned and real estate company-owned condominiums, which are leased as rental apartments. Thanks to a study conducted by Berntsson and Halldin (2012), it has been possible to conduct a study on the management over time. A literature study has been part of the study to obtain background information on the formation of condominiums with the necessary rights and how the equivalent of condominiums works abroad regarding management.The purpose of the study was to examine how the management was perceived twelve years after the previous survey and to map any differences and to find out if the change in the role of the real estate company had had an impact on how the company is perceived. In addition, the residents' knowledge of the boundaries between individual condominiums and shared facilities was investigated. The study showed that a larger proportion are positive towards the community association today than in 2012. The proportion of people who expressed themselves negatively about the company has decreased. The results showed that when the area was new, there was a certain optimism about the combination of rental apartments and ownership rights in the same area, also in other places in Sweden. A clear change can be discerned in this study when the uncertainty among the respondents is now significantly greater.

The purpose of this paper is to examine the pros and cons of compulsory acquisition of rooftop space for mass upscaling of solar panels. It attempts to find what uses a legal tool for compulsory acquisition could bring to society, as well as what the cost of such a tool would mean for each landowner. By looking at existing law it is also the hope of the writer to establish whether there is already a functioning way to accomplish this kind of mass development of rooftop-mounted solar panels. While it is not included in the paper to describe what a potential new piece of law would look like, it concludes that if Sweden was to implement a way to accomplish a mass development of this kind, it should be done by creating a separate act to limit how and by whom the compulsory acquisition can be performed. 

Our complex planet is continuously undergoing temporal and spatial changes. In this context, ongoing processes in the Earth subsystems (geosphere, biosphere, cryosphere, hydrosphere, and atmosphere) cause changes in the gravity field of the Earth across a wide range of temporal and spatial scales. Accordingly, by both spatially and temporally tracing our planet’s ever-changing gravity field, scientists can better constrain the underlying processes contributing to such dynamic changes of mass distribution within the Earth system. Monitoring the Earth’s gravity field and its temporal variations is essential, among others, for tracking disasters and specifying land areas with a high risk of flooding, earthquakes, and droughts, movements of tectonic plates, and providing accurate positioning through satellite positioning technology. On short-term timescales, temporal variations in the Earth’s gravity field are mainly caused by the movement of water in its various forms. Accordingly, sea-level variations and ice-sheet and glacier changes, which are known as critical indicators of global warming and climate change, can be accurately monitored by tracking the Earth’s gravity field changes. Since there is a close link between water redistribution and the Earth’s energy cycle, climate system, food security, human and ecosystem health, energy generation, economic and societal development, and climate extremes (droughts and floods), it is essential to accurately monitor water mass exchange between the Earth system components. Among all observational techniques, satellite gravimetry has provided an integrated global view of ongoing processes within the Earth system. The current generation of satellite gravimetry missions (the Gravity Recovery and Climate Experiment (GRACE) mission and its successor, GRACE Follow-On) has dramatically revolutionized our understanding of dynamic processes in the Earth’s surface and, consequently, has significantly improved our understanding of the Earth’s climate system. By considering different aspects of studying the Earth’s gravity field, this thesis brings new insights to the determination and analysis of the mass change in the Earth system. First, by studying the shortcomings of the common techniques of estimating the geoid potential, a new approach is examined that simultaneously estimates the geoid potential, W0, and the geometrical parameters of the reference Mean Earth Ellipsoid (MEE). In this regard, as the geoid needs to be considered as a static equipotential surface, the sensitivity of the estimations to the time dependent Earth’s gravity field changes is studied. Secondly, relying on the GRACE monthly gravity fields and the complementary observational techniques, and by pushing the limit of GRACE, mass redistribution over land and ocean is investigated. Within the ocean, satellite altimetry and Argo products are utilized along with the GRACE monthly solutions for quantifying the global barystatic sea-level change and assessing the closure of the global mean sea level budget. Over land, a region with relatively high temporal mass change (oil and water extraction) is chosen in which by taking advantage of having in-situ observations and hydrological models, the ability of GRACE products in quantifying the changes in groundwater storage is studied. In this frame, for both the ocean and land studies, different aspects of the processing of GRACE monthly gravity fields are investigated and GRACE inherent errors are addressed appropriately to arrive at reliable and accurate estimates of the Earth’s surface mass change. As the final contribution in this thesis, a rigorous analytical model for detecting surface mass change from the time-variable gravity solutions is proposed and examined in different case studies of surface mass change. Since the launch of the GRACE twin satellites, the GRACE(-FO) time-varying gravity fields are conventionally converted into the surface mass change using a spherical analytical model that approximates the Earth by a sphere. More recently, the analytical mass change detection model has been improved by considering an ellipsoid as the shape of the Earth, which improved the previous estimations of surface mass change, especially over high latitudes with relatively large mass change signals. However, by taking into account the real shape of the Earth and considering more realistic assumptions, a new analytical solution for the problem of surface mass change detection from the time-varying gravity fields is proposed in this thesis. It is shown that the simplistic spherical and ellipsoidal geometries are no longer tenable and the new model surpasses the common spherical approach and its ellipsoidal version.

Sea level changes over time because of water mass exchange among the oceans and continents, ice sheets, and atmosphere. It fluctuates also due to variations of seawater salinity and temperature known as the steric contributor. GRACE-based Stokes coefficients provide a valuable source of information, about the water mass exchange as the main contributor to the Earth’s gravity field changes, within decadal scales. Moreover, measuring seawater temperature and salinity at different layers of ocean depth, Argo floats help to model the steric component of Global Mean Sea Level. In this study, we evaluate the Global Mean Sea Level (GMSL) budget closure using satellite altimetry, GRACE, and Argo products. Hereof, considering the most recent released GRACE monthly products (RL06), we examine an iterative remove-restore method to minimize the effect of artifact leaked large signal from ice sheets and land hydrology. In addition, the effect of errors and biases in geophysical model corrections, such as GIA, on the GMSL budget closure is estimated. Moreover, we quantify the influence of spatial and decorrelation filtering of GRACE data on the GMSL budget closure. In terms of the monthly fluctuations of sea level, our results confirm that closing the GMSL budget is highly dependent on the choice of the spatial averaging filter. In addition, comparing the trends and variations for both the global mean sea level time series and those estimated for mass and steric components, we find that spatial averaging functions play a significant role in the sea level budget closure.

Time-varying spherical harmonic coefficients determined from the Gravity Recovery and Climate Experiment (GRACE) data provide a valuable source of information about the water mass exchange that is the main contributor to the Earth’s gravity field changes within a period of less than several hundred years. Moreover, by measuring seawater temperature and salinity at different layers of ocean depth, Argo floats help to measure the steric component of global mean sea level (GMSL). In this study, we quantify the rate of barystatic sea-level change using both GRACE RL05 and RL06 monthly gravity field models and compare the results with estimates achieved from a GMSL budget closure approach. Our satellite altimetry-based results show a trend of 3.90 ± 0.14 mm yr−1 for the GMSL rise. About 35% or 1.29 ± 0.07 mm yr−1 of this rate is caused by the thermosteric contribution, while the remainder is mainly due to the barystatic contribution. Our results confirm that the choice of decorrelation filters does not play a significant role in quantifying the global barystatic sea-level change, and spatial filtering may not be needed. GRACE RL05 and RL06 solutions result in the barystatic sea-level change trends of 2.19 ± 0.13 mm yr−1 and 2.25 ± 0.16 mm yr−1, respectively. Accordingly, the residual trend, defined as the difference between the altimetry-derived GMSL and sum of the steric and barystatic components, amounts to 0.51 ± 0.51 and 0.45 ± 0.44 mm yr−1 for RL05 and RL06-based barystatic sea-level changes, respectively, over January 2005 to December 2016. The exclusion of the halosteric component results in a lower residual trend of about 0.36 ± 0.46 mm yr−1 over the same period, which suggests a sea-level budget closed within the uncertainty. This could be a confirmation on a high level of salinity bias particularly after about 2015. Moreover, considering the assumption that the GRACE-based barystatic component includes all mass change signals, the rather large residual trend could be attributed to an additional contribution from the deep ocean, where salinity and temperature cannot be monitored by the current observing systems. The errors from various sources, including the model-based Glacial Isostatic Adjustment signal, independent estimation of geocenter motion that are not quantified in the GRACE solutions, as well as the uncertainty of the second degree of zonal spherical harmonic coefficients, are other possible contributors to the residual trend.

The geoid, according to the classical Gauss–Listing definition, is, among infinite equipotential surfaces of the Earth’s gravity field, the equipotential surface that in a least squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth’s global gravity models (GGM). Although, nowadays, satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zero-degree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the mean Earth ellipsoid (MEE). The main objective of this study is to perform a joint estimation of W0, which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite-component of a quasi-stationary GGM to estimate W0. In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e., mean sea surface and mean dynamic topography models. Moreover, as W0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth’s gravity field changes as well as the time-dependent sea level changes on the estimation of W0. Our computations resulted in the geoid potential W0 = 62636848.102 ± 0.004 m2 s−2 and the semi-major and minor axes of the MEE, a = 6378137.678 ± 0.0003 m and b = 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM = (398600460.55 ± 0.03) × 106 m3 s−2.

According to the classical Gauss–Listing definition, the geoid is the equipotential surface of the Earth’s gravity field that in a least-squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth’s Global Gravity Models (GGM). Although nowadays, the satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zero-degree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the Mean Earth Ellipsoid (MEE). In this study, we perform joint estimation of W0, which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface, and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite componentof a quasi-stationary GGM to estimate W0. In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e. mean sea surface and mean dynamic topography models. Moreover, as W0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth’s gravity field changes as well as the time-dependent sea-level changes on the estimation of W0. Our computations resulted in the geoid potential W0 = 62636848.102 ± 0.004 m2s-2 and the semi-major and –minor axes of the MEE,a = 6378137.678 ± 0.0003 m and b = 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of the GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM = (398600460.55 ± 0.03) × 106 m3s-2.

The electrification of the transport sector is dependent on the establishment of new charging infrastructure for electric vehicles. In order to achieve Sweden’s environmental goals, the government has commissioned Lantmäteriet to chart the obstacles of establishing charging infrastructure within joint facilities. During the charting, Lantmäteriet has observed the fact that joint property associations that manage joint facilities for garage and parking purposes receive government grants for charging infrastructure, even though the joint facility does not include charging infrastructure. This paper aims to investigate how joint property associations manage permit issues and agreements regarding charging infrastructure, when charging infrastructure is not included in the joint facility. This paper also examines if these issues are taken into account in the grant processing by Naturvårdsverket. The aim of this paper is to generate new knowledge that can be used in Lantmäteriet’s work. The study has been carried out through interviews with joint property associations and through communication with representatives from Naturvårdsverket. The results show that it is common for joint property associations to set up charging infrastructure contrary to the purpose of the facility. Furthermore, it is stated that ignorance and the fact that the associations consciously make decisions against the purpose of the facility due to time and cost causes, are the main reasons for the establishment. The authors also state that Naturvårdsverket and Lantmäteriet have different views on when and how charging infrastructure can be considered a part of a joint property. Furthermore, it is concluded that inconsistent legislation makes it difficult for ordinary people who administer joint property associations to comply with current laws and regulations.

In the event of a traffic accident, it is often important to restore the site to its normal condition as fast as possible. Occasionally, the accident scene must be documented so that the cause of the accident can be investigated at a later stage. Traditionally, this work has been performed by taking pictures of the site and measuring different distances. Lately, terrestrial laser scanning has also become a reliable alternative. With that said, it is possible that photogrammetry and other types of laser scanning also could be utilized to achieve similar results.   

The aim of this study is to investigate how handheld laser scanning and UAS photogrammetry can be used to document a traffic accident. This is achieved by examining the positional uncertainty and visual quality of the point clouds. Moreover, the advantages and disadvantages of each method are explored, for instance in terms of time consumption and costs, in order to finally come to a conclusion of which method is best suited for documenting a traffic accident.

A traffic accident with two involved cars was staged and initially laser scanned with the handheld laser scanner Leica BLK2GO. Thereafter, pictures were collected with the unmanned aerial vehicle Leica Aibot followed by the creation of a reference point cloud with the terrestrial laser scanner Leica C10. By comparing the coordinates of control points in the reference point cloud with the coordinates of the corresponding control points in the two other point clouds, their positional uncertainty could be determined.

The results of the study show that both the point cloud produced by the handheld laser scanner and UAS photogrammetry have a positional uncertainty (standard uncertainty) of 0.019 m. Both methods are applicable for documenting a traffic accident but compared to terrestrial laser scanning, the point clouds are deficient in different ways. BLK2GO produces a relatively dark point cloud and dark objects are reproduced worse than lighter objects. In the point cloud produced by Leica Aibot, there were noticeable cavities in the bodies of the cars. Handheld laser scanning is a time-efficient method while UAS photogrammetry can be performed at a lower cost.

In conclusion, it is not possible to arrive at an unambiguous conclusion with regards to which method that is best suited for documenting a traffic accident. The choice depends on the prevailing circumstances at the accident scene.

The term green infrastructure captures the need to conserve biodiversity and to sustain landscapes’ different ecosystem services. Maintaining green infrastructures through protected areas, management and landscape restoration requires knowledge in geography, spatial data about biophysical, anthropogenic and immaterial values, spatial comprehensive planning, and thus geographical information systems (GIS). To understand land use planning practices and planning education regarding GIS in Sweden we interviewed 43 planners and reviewed 20 planning education programmes. All planners used GIS to look at data but did not carry out spatial analyses of land covers. BSc programmes included more GIS than MSc programmes but very few taught analyses for spatial planning. As key spatial planning actors, municipalities’ barriers and bridges for improved GIS use for collaborative learning about green infrastructures are discussed. A concluding section presents examples of how GIS can support spatial planning for green infrastructures.

Infrastructure investments is a large part of the regional development in Sweden, researchers in the subject agrees that investment in infrastructure generate increased economic development, one thing they still share a disagreement in which calculating methods are suitable. Are there any winners or losers in infrastructure projects, for example, smaller cities in the countryside where highways have previously passed, have they benefited from a quicker and easier commuting to the city, or have they been adversely affected when the highway has been given a new stretch?

This research report focuses in one of the largest infrastructure investments in northern Sweden, European road 4 (E4) through Sundsvall. The research, combined with location-based sales comparison method and local analyzes, will show what effect market values will have on the houses real estate’s and what influence the road construction might have regarding to the values of the properties.

The results of these studies are shown trough the average changes in property prices in the areas of Njurundabommen, Nedre Haga/Skönsberg, Nolby/Kvissleby and Västbo. However, the result was shown to have too few transactions, which is common in local level sales analyzes. This generates uncertainty in the result, meaning that the values can be large in relation to the actual sales development. The uncertainty was minimized in the results by merging two similar areas, which finally gave a result that indicates that the areas in the study had a more negative development towards Sundsvall and Sweden, since the area received a new infrastructure in the form of the E4 Sundsvall.

Fungerande infrastruktur är viktigt för att samhället ska fungera. Det är därför också viktigt att Trafikverket och kommuner får tillgång till mark för utbyggnad av bland annat vägar och järnvägar. Samtidigt görs ett intrångi någons enskilda äganderätt. Markåtkomst för dessa ändamål kan ske med en frivillig överenskommelse mellan parterna men i vissa fall tvingas Trafikverket och kommuner att tvångsvis förvärva marken.

Syftet med arbetet är att ta reda på om Trafikverket och kommuner har några särskilda principer för markåtkomst gällande utbyggnad av vägar och järnvägar, samt försöka ta reda på hur fastighetsägare behandlas i en sådan process. Målet är att kunna bidra med ett bättre underlag för både Trafikverket och kommuner vad gäller deras riktlinjer för markåtkomst. För att besvara frågeställningarna i studien har intervjuer med ett antal kommuner samt sakkunniga inom Trafikverket genomförts.

Resultatet visade att det finns riktlinjer för hur själva markåtkomsten ska hanteras men ingen respondent ansåg att de hade några riktlinjer för hur en fastighetsägare ska behandlas i processen. Den största skillnaden mellan Trafikverket och kommunerna var att kommunerna nästan aldrig använder tillfälliga nyttjanderätter i detaljplanplanen utan förlitar sig på frivilliga överenskommelser ifall de behöver tillgång till mark, medan Trafikverket använder sig utav tillfälliga nyttjanderätter i väg- och järnvägsplan i större utsträckning. I slutsatsen framgår det att den främsta faktorn för att nå en överenskommelse är tidig kontakt med fastighetsägare där det är viktigt att visa förståelse för dennes situation. Många respondenter var också enade om att det är viktigt att hela tiden hålla fastighetsägare informerade om vad som ska ske och hur deras fastighet kommer att påverkas. Trots att det inte finns fastställda riktlinjer för hur en fastighetsägare ska behandlas verkar de flesta ändå utgå från liknande ”principer”. 

This study is a bachelor thesis at the Study Programme in Land Management with financial/legal orientation at the University of Gävle. 

Municipalities in Sweden are voluntarily responsible for road maintenance and financing of private roads, even though the actual responsibility is imposed on the property owners. One of the reasons behind these occurrences is the mergers of the municipalities that took place in the sixties and seventies, which made the remaining municipalities take over the management of the private roads. Over the decades, municipalities may decide to return these voluntarily managed private roads to the property owners. The returning of these private roads to the property owners is done through facility procedures to secure a long-lasting road maintenance. 

The aim of this study is to investigate these types of facility procedures that have occurred in reference to transitions from municipal to private management of private roads. The objective is to create a base of knowledge that the Swedish municipalities and cadastral authorities can use when working with these kinds of phenomenon. To reach the aim and objective, interviews have been done with five experts in the field and with five joint property management associations. These interviews provide valuable information from both experts and property owners. Five cadastral dossiers have been analysed to give a deeper understanding of the cadastral process and to supplement the interviews. 

The study shows that the road maintenance, in the analysed and the interviewed cases, often gets better when a private road’s management transfers from municipal to private. The property owners sometimes remain frustrated after the ending of the cadastral process, but this frustration has not been shown to affect the road maintenance in a negative way. In order to achieve a smooth cadastral process that leads to an appropriate management, the municipalities should assist the property owners with the application. As a starting point, the State cadastral authority should handle these types of cases to achieve better objectivity and neutrality, even though there is a municipal cadastral authority available. It is at last important that the cadastral process include communication, dialogue and clarity, and by doing so making the property owners aware of the situation.

Digital terrain models (DTMs) are a commonly used tool in planning various development projects within the state, municipalities, and the private sector. In planning for road and rail construction, the Swedish technical specification SIS-TS21144:2016 is often used as a document for controlling the production process of DTMs. Given that new technology opens the possibilities for faster, more efficient, and climate-smart data collection, this study aims to evaluate Unmanned Aerial System (UAS) with Light Detection and Ranging (LiDAR) from YellowScan and to evaluate the measurement uncertainty in height. In this study, the results of the study are compared with class 2 SIS-TS 21144:2016 for the flight heights 50 m and 80 m and the scanning angles 0 (in nadir), 10, 20 and 40 degrees. The site of the study is located just southwest of Gävle in a closed gravel pit with both hard packed and slightly looser substrates. The size of the study area was limited to 200 x 300 m, equivalent to 6 hectares. With Global Navigation Satellite System (GNSS) equipment, two control points were measured with Network-RTK (Real Time Kinematic). Subsequently, a control network of eight points was created. A total of 26 control grids were measured for comparisons of collected LiDAR data. The data collection was carried out with the Unmanned Aerial Vehicle (UAV) GeoDrone X4L equipped with LiDAR Scanner YellowScan Surveyor with an integrated Inertial Measurement Unit (IMU) from Applanix. Together, these units formed an UAS that could be remotely controlled and communicate its position. All processing was performed in software from Terrasolid, based on data from the flight route that was first processed in YellowScan CloudStation. The points were classified to distinguish ground points used in the generation of the DTM. An adjustment of the point cloud was made with the intention of raising ground level points to reduce the noise present in the data. The control grids could then be compared to the DTM and analysed. The results of the study show that YellowScan Surveyor achieves a Root Mean Square (RMS) in height of 0,024 m at 50 meters flight altitude, which equals 0,047m expanded measurement uncertainty (2 sigma level, 95 %). Even at 80 meters, relatively low uncertainty is achieved with an RMS of 0,040 m. The results of the study indicate that the influence of measurements at a wider scanning angle is not the only factor that deteriorates the results.   

Feeling safe is important for residents in their neighborhoods, but how do residents living in an area rumored to be unsafe perceive safety? This case study examined the perceived safety in a vulnerable area (Swedish: Utsatt område) in Gävle, Sweden. These vulnerable neighborhoods fall under the Swedish million housing program that consist of residential areas with large and high resident buildings that are often densified. This study aimed to examine the residents’ perception of safety in a neighborhood with the same conditions, in addition to evaluate crime prevention in the area using crime prevention through environmental design principles. territoriality, natural surveillance, activity support and access control. The aim of this study was achieved by using the following methods: CPTED inventory, safety walks and a survey. The safety walk was conducted with residents of the area. The inventory showed that crime prevention in the area is considered low, however, the results from safety walk suggest that the residents perceive the area as moderately safe. This study provides some suggestions in order to provide better crime prevention and better perception of safety in the area.Examples among the suggestions were to better the lighting and create more pedestrian crossovers on the car-based roads to decrease possible barrier effects. 

The purpose of this study is to investigate and provide a picture of how Swedish municipalities are working to implement the Convention on the Rights of the Child (CRC) in their planning process. The study was conductedby sending out a survey to all 290 municipalities in Sweden in order to get an idea of the methods and approaches used by municipalities. The survey resulted in 123 answers which the result of the study then was based on. It was also investigated which of three perspectives on children by the definition of the National Board of Housing, Building and Planning (The Children’s perspective, The Children’s rights perspective, and the Child perspective) Swedish municipalities use to give children more influence and participation in their planning process. The study also investigated whether there is a possible difference in the work of municipalities depending on their population size, and its causes. Chi-square tests were used to analyze the municipalities' responses to the questionnaire and to find possible correlations between variables such as the size of the municipality's population and their answers to the questionnaire questions. A possible correlation would show that there is a difference based on the population of the municipality and their progress to implement the CRC. The responses of the municipalities will also be categorized using a UNICEF participation model, in which the municipalities are placed at different levels in the model based on the level of participation by children in the planning process. The results show that Swedish municipalities have made different progress and are working in different ways with the implementation of the CRC. Analyses based on the available data reveal a number of associations between the size of the municipalities' populations and the way in which children's participation in the planning process is handled. Larger municipalities in terms of population give children a more participatory role in their planning, which were shown by the higher level of percentage of child participation in more populated municipalities. While smaller municipalities in terms of population use methods, such as workshops, that give children a greater opportunity to express their views and opinions in a meaningful way. The study shows that the majority of the participating municipalities meet the minimum requirements of the participation model, but there is room for improvement in the approach to children as an important asset in spatial planning. If more municipalities choose to use the Child perspective, municipalities can have an approach that gives children a greater chance to be involved and have their opinions heard, which would then be used as a basis for decisions.

We face a number of uncertainties, challenges and risks, known and unknown, many of which are linked to global changes. Urban development must be planned to become sustainable in the long term despite future changes and to succeed, planning must handle uncertainties. The current view of sustainability has resulted in a planning ideal that strives for sustainability as a vision of an ideal structure and design. The research on resilience question this by asking how something static can be sustainable in the face of uncertainties and future changes. The work towards sustainability must focus on increasing the capacity of cities to be resilient. Cities which are resilient have the capacity to adapt to future changes while retaining the same function, structure and identity.

Näringen is an existing industrial area in Gävle which has been designated suitable for a larger urban development exploitation project. The study aims to investigate how resilience is incorporated into the planning and development process of Näringen. The study compared Gävle municipality's intentions and ambitions for the development of Näringen in relation to theoretical principles for increased resilience in urban environment. The comparison between theory and practice was done through a qualitative content analysis of policy documents and interviews with two officials.

The findings show that the intentions and ambitions of Gävle municipality in some ways are in line with the principles for increased resilience in cities but miss important aspects within the principles. The municipality strives for novel and innovative ways of planning which the principles for resilience can contribute with. One problem which can lead to reduced sustainability and resilience is that socio-economic prerequisites and conditions are prioritized over natural geographical ones.

Implementation of the principles in municipal planning is not easily achieved in all situations because the principles in some respects overlap depending on the scale. Gävle Municipality's view of sustainability is also not in line with the approach that the research of resilience advocates, that we all live and operate in complex social-ecological systems. Resilience deals with complex theories and attempts to implement resilience principles without an understanding for the complexity of systems can lead to an unsuccessful outcome. The resilience principle adaptive planning holds the potential for continuous learning about social-ecological systems and is considered the principle that should be prioritized in planning for sustainability through resilience.

To live on a house boat is a housing form that still is establishing on the housing market, but the regulations about this are almost non-existent. You cannot find any legislation regarding living on the water today and there are doubts about what applies for grants of house boats at a berth. The rules about establishment of house boats falls between the “plan- och bygglagen” and the rules of the harbor, which makes it difficult to say which one of the grant agreement that is the most applicable for the property owner and the person who wants to live on the water. To get answers the questions in this thesis interviews were performed with different parties and different cadastral procedures were analyzed regarding water properties. The interviews were completed by phone interviews with a semi structured method and with a few respondents the questions were put through email. In this thesis a few different respondents were asked to answer the questions, this to see different perspectives of the grant of berth. The different respondents that answered the questions were a few contract managers, usufructuary, a real estate agent, a lawyer, a company which produce house boats and a cadastral surveyor. The analysis of the cadastral procedures gave a deeper understanding how property formation on water can be done. The respondents in this thesis perceived the Swedish law as incomplete as the authors of this thesis regarding living on the water. The results show that the law can be applied in different ways depending on which type of housing form it is. The study shows that the best solutions for floating houses should be property formation, that will make the house real property and will make financing of the house possible. When house boats, which are formed like ships, the study shows that the best solutions for this housing form is to apply ground lease in general with the longest grant as possible, which is 25 years. To have ground lease in general as a solution makes it hard for the house boat owners to get a loan.

Hydrological analyses are becoming a more common tool for being able to prepare for eventual floods. As natural disasters such as these will increase in the future as higher temperatures and increased precipitation Fagersta municipality has begun producing cloudburst maps. The aim of this study is to investigate the effects that resolution has on hydrological modelling and cloudburst mapping. Another goal of the study is to examine if the Swedish national height model (NH) is suitable for use in forthcoming cloudburst analyses.The study area is located in the city center of Fagersta and is divided into two areas, one northwest of the hospital named Bergslagssjukhuset and the other over the district Västanfors. Fagersta municipality has carried out a laserscanning which is used to create the different data sets in the analyses. The measured points have been preworked in Cyclone 3DR and calculated in FME Workbench as a TIN (Triangulated Irregular Network). Digital elevation models (DEM) were later on created with the following resolutions;0,5 m, 1 m, 2 m, 5 m, 10 m, 25 m and 50 m. The recently produced NH was also used as a data set. It consists of a DEM with a resolution of 1 m. The cloudburst mapping was implemented in ArcMap 10.8 with the method to locate blue spots that run the risk of being flooded. Hydrological modelling was applied with the aim of producing stream networks which presents where water will flow in case of a flood. The results were compared by using feature agreement statistics which showed how comparable the data sets were to the reference resolution of 0,5 m. Additional validations were made by using Fagersta municipality's own cloudburst map which was carried out in 2017 by SMHI on behalf of Länsstyrelsen. The datawas compared to 0,5 m, 1 m and NH 1 m.Results from the cloudburst mapping showed that NH compares well with Fagerstas data set. It also showed that the spread of blue spots generally increases and the fill-up valuedecreases at a lower resolution. Cross sections from the blue spots showed that this also generalizes depth. The hydrological modellings strengthens that lower resolutions generalizes areas. A conclusion can be drawn that the resolutions of 10 m and up should not be used in a precise analysis. They can however be used for easy-reference mapping. Another conclusion was drawn that NH is suitable for use as a data set in cloudburst mapping for most purposes. A data set with a better point density should however be used in analyses which require a more detailed result.

Conducting compulsory land transfer is something that is not applied more often than land transfers that have an agreement between the parties. Despite this, it does happen that the parties do not agree, and that the surveyor will have to carry out the handling in a way that results in a compulsory land transfer. It is a complicated process that involves special paragraphs for this purpose only. In addition to the applicable chapter, the surveyor must also consider the protection of property, which originates in Sweden's constitution. Property protection is a condition that, despite its early origins, is becoming more relevant after the NJA 2018 p. 753.

The aim of the research conducted by the authors is to contribute to the elucidation of clearer guidelines for how surveyors can proceed in their handling of compulsory land transfer. Based on the research question, proposals are presented for how and when the principle of proportionality can be tested.

To answer the research question, the authors apply different qualitative research methods and then compare these with each other in the preparation of the result. A legal dogmatic method has been applied through an analysis of how paragraphs are used in practice. In addition, interviews with surveyors and lawyers have been conducted. Why two different occupational groups were interviewed is to discuss the subject from the perspective of different occupational groups. The implementation is based on a semi-structured approach and took place through Skype and telephone communication. The respondents' responses and the legal dogmatic analysis show that surveyors and courts are on the same track for the conditions to be tested in the application of compulsory land transfer. However, the result shows an ambiguity regarding when the property protection is to be tested and important definitions for the test in the strict sense. The conclusions of the research show that NJA 1996 p.110 stated that the protection of property was fulfilled by examining Chapter 5. The Property Formation Act (SFS 1970:988). More judgments and guidelines are needed to establish an official review system in mandatory land transfer. What can be done within a relatively short span of time is to develop an existing handbook and to define the definition of what an important interest means in a real estate development context.

The utilization of remote sensing observations to monitor essential climate variables (ECVs) has become increasingly important in studying their regional and global impacts, as defined by the Global Climate Observing System (GCOS). Understanding the Earth’s surface conditions, including soil moisture runoff, snow, temperature, precipitation, water vapour, radiation, groundwater and sea surface height (SSH), can positively impact the environment and ecosystems. Here, the authors present an overview of how global navigation satellite systems (GNSS) can be employed for environmental monitoring, with a particular focus on sea surface height monitoring. This includes examination of the advantages and disadvantages of utilizing a network of permanent GNSS stations for monitoring sea level rise along shorelines.

Human-made infrastructure, such as dams, bridges, tunnels, and high towers, requires highly precise geodetic control networks and continuous monitoring to detect potential failure risks and plan civil engineering maintenance works. In classical 2D geodetic networks, reducing slope distances to horizontal ones is an important task for engineers. The common practice for this reduction involves using vertical angles and applying trigonometric rules. However, using vertical angles introduces systematic errors, primarily due to air refraction, deflections of the vertical (DOV), and the geometric effects of the reference surface, whether it is a sphere or an ellipsoid. Therefore, employing vertical angles in establishing geodetic control networks in 2D is challenging due to these systematic errors. To mitigate the refraction and DOV effects, reciprocal observations of vertical angles can be considered, especially if the elevation differences are small. In this study, we quantify these effects and propose an innovative solution to eliminate these systematic errors in small-scale geodetic networks. Specifically, we propose a new technique that does not rely on vertical angles for the reduction of distances, which is called the network-aided method. Thus, the geometric, physical, and refraction effects cancel out in this method. The results of this study hold significant importance for surveying guidelines. The main advantage of the proposed method is less fieldwork and, hence cost reduction since there is no need for different OFF-construction (reference) and ON-construction (monitoring) networks. Consequently, the number of network points will be less than in traditional networks. There is no need for reciprocal observations since vertical angles are not utilized, while the precision remains equal or even superior (in terms of quality factors i.e., higher redundancy numbers and smaller error ellipses).

Most human-made infrastructures require regular deformation monitoring to detect failure risks and plan maintenance works. Continuous health monitoring is crucial for assessing infrastructure stability and plays a key role in mitigating damages and disasters within various environmental and engineering contexts. Structural deformation monitoring methods can be divided into two methods: geodetic and non-geodetic. Geodetic techniques enable the detection of displacements with respect to an external geodetic reference system, while non-geodetic methods can detect relative, internal changes within the monitored object. Both methods will be covered in this lecture note. In addition, after presenting the theoretical background and principle of the least-squares approach in Chapter 1, the necessary recommendations and guidelines for deformation monitoring using geodetic and non-geodetic methods will be provided.

The aim of this lecture note is to provide a theoretical background in the field of deformation monitoring, specifically using geodetic methods, for engineers, students, and researchers. One of the motivations behind this effort is the lack of references that adequately present the methods and recommendations for this purpose.

Airborne mobile mapping is one of the most important data acquisitionmethods for producing topographical maps and extracting terrain featuresfrom aerial images. The interest in 3D geospatial data is expanding, andtechnology is growing at an unprecedented speed with new digitalcamera mapping systems. Different sensors are used for data acquisitionin modern airborne photogrammetry. GNSS/INS (Inertial NavigationSystems) applications are developing, especially for direct georeferencingin airborne photogrammetry. Achieving accurately georeferencedproducts from the integration of GNSS and INS requires removingexisting systematic errors/bias, due to different reference systems, in themobile mapping systems. The collected data should refer to the samereference system; otherwise, it can impose a systematic shift in theresults. In this presentation, we assess the impact of the deflection ofverticals (i.e. the angle between the plumb line and normal to thereference ellipsoid) on the obtained horizontal and vertical coordinates.

The Earth's mass redistribution due to deglaciation and recent ice sheet melting causes changes in the Earth's gravity field and vertical land motion in Greenland. The changes are because of ongoing mass redistribution and related elastic (on a short time scale) and viscoelastic (on time scales of a few thousands of years) responses. These signatures can be used to determine the mantle viscosity. In this study, we infer the mantle viscosity associated with the glacial isostatic adjustment (GIA) and long-wavelength geoid beneath the Greenland lithosphere. The viscosity is determined based on a spatio-spectral analysis of the Earth's gravity field and the land uplift rate in order to find the GIA-related gravity field. We used different land uplift data, that is, the vertical land motions obtained by the Greenland Global Positioning System (GPS) Network (GNET), gravity recovery and climate experiment (GRACE) and glacial isostatic adjustment (GIA) data, and also combined them using the Kalman filtering technique. Using different land uplift rates, one can obtain different GIA-related gravity fields. As shown in this study, the mantle viscosities of 1.9 × 1022 Pa s and 7.8 × 1021 Pa s for a depth of 200–700 km are obtained using ICE-6G (VM5a) model and the combined land uplift model, respectively, and the GIA-related gravity potential signal

The Earth’s mass redistribution due to deglaciation and recent ice sheet melting causes changes in the Earth’s gravity field and vertical land motion in Greenland. The changes are because of ongoing mass redistribution and related elastic (on a short time scale) and viscoelastic (on time scales of a few thousands of years) responses. These signatures can be used to determine the mantle viscosity. In this study, we infer the mantle viscosity associated with the glacial isostatic adjustment (GIA) and long-wavelength geoid beneath the Greenland lithosphere. The viscosity is determined based on a spatio-spectral analysis of the Earth’s gravity field and the land uplift rate in order to find the GIA-related gravity field. We used and evaluated different land uplift data, i.e. the vertical land motions obtained by the Greenland Global Positioning System (GPS) Network (GNET), GRACE and Glacial Isostatic Adjustment (GIA) data. In addition, a  combined land uplift rate using the Kalman filtering technique is presented in this study. We extract the GIA-related gravity signals by filtering the other effects due to the deeper masses i.e. core-mantle (related to long-wavelengths) and topography (related to short-wavelengths). To do this, we applied correlation analysis to detect the best harmonic window. Finally, the mantle viscosity using the obtained GIA-related gravity field is estimated. Using different land uplift rates, one can obtain different GIA-related gravity fields. For example, different harmonic windows were obtained by employing different land uplift datasets, e.g. the truncated geoid model with a harmonic window between degrees 10 to 39 and 10 to 25 showed a maximum correlation with the GIA model ICE-6G (VM5a) and the combined land uplift rates, respectively. As shown in this study, the mantle viscosities of 1.6×1022 Pa s and 0.9×1022 Pa s for a depth of 200  to 650  km are obtained using ICE-6G (VM5a) model and the combined land uplift model, respectively, and the GIA-related gravity potential signal.

Remote sensing observations of Essential Climate Variables (ECVs) provide a means of studying their global and regional impacts. Coastal GNSS stations measure water levels using GNSS Reflectometry (GNSS-R) technique by determining the vertical distance between the antenna and the water surface. In this study, GNSS-R data from four stations over three months were used to estimate sea surface heights (SSH) and assess accuracy using nearest tide gauge observations. Results showed that GNSS signals from GPS, GLONASS, Galileo, and BeiDou were accurate for the SSH estimation. In addition, 145 significant tidal frequencies were extracted using the GNSS-R and tide gauge time series by employing the Least Square Harmonic Estimation (LS-HE) approach. The study demonstrates the usefulness of GNSS-R for tide studies and its potential use alongside tide gauge measurements in coastal locations.

The principle of isostasy plays an important role to understand the relation between different geodynamic processes. Although, it is difficult to find an exact method that delivers a complete image of the Earth structure. However, gravimetric methods are alternative to provide images of the interior of the Earth. The Earth’s crust parameters, i.e. crustal depth and crust-mantle density contrast, can reveal adequate information about the solid Earth system such as volcanic activity, earthquake and continental rifting. Hence, in this study, a combine Moho model using seismic and gravity data is determined to investigate the relationship between the isostatic state of the lithosphere and seismic activities in East Africa. Our results show that isostatic equilibrium and compensation states are closely correlated to the seismicity patterns in the study area. For example, several studies suggest that African superplume causes the rift valley, and consequently differences in crustal and mantle densities occur. This paper presents a method to determine the crustal thickness and crust-mantle density contrast and consequently one can observe low-density contrast (about 200 kg/m3 ) and thin crust (about 30 km) near the triple junction plate tectonics in East Africa (Afar Triangle), which confirms the state of overcompensation in the rift valley areas. Furthermore, the density structure of the lithosphere shows a large correlation with the earthquake activity, sub-crustal stress and volcanic distribution across East Africa.

There is an exceptional opportunity of achieving simultaneous and complementary data from a multitude of geoscience and environmental near-earth orbiting artificial satellites to study phenomena related to the climate change e.g. sea level change, ice melting, soil moisture variation, temperature changes, and earth surface deformations. In this study, we focus on permafrost thawing and its associated gravity change, and organic material changes using GRACE data and other satellite- and ground-based observations. The estimation of permafrost changes requires combining information from various sources, particularly using the gravity field change, surface temperature change, and GIA. The most significant factor for careful monitoring of the permafrost thawing is the fact that this process could be responsible for releasing an additional enormous amount of greenhouse gases emitted to the atmosphere, most importantly to mention Carbone dioxide and Methane that are currently stored in the frozen ground. The results of a preliminary numerical analysis reveal a possible existence of a high correlation between the secular trends of greenhouse gases, temperature and equivalent water thickness in the selected regions. Furthermore, according to our estimates based on processing the GRACE data, the groundwater storage attributed to the due to permafrost thawing increased at the annual rates of 3.4, 3.8, 4.4 and 4.0 cm, in Siberia, northern Alaska, and Canada. Despite a rather preliminary character of our results, these findings indicate that the methodology developed and applied in this study should be improved by incorporating the in situ permafrost measurements.

GNSS/INS applications are being developed, especially for direct georeferencing in airborne photogrammetry. Achieving accurately georeferenced products from the integration of GNSS and INS requires removing systematic errors in the mobile mapping systems. The INS sensor's uncertainty is decreasing; therefore, the influence of the deflection of verticals (DOV, the angle between the plumb line and normal to the ellipsoid) should be considered in the direct georeferencing. Otherwise, an error is imposed for calculating the exterior orientation parameters of the aerial images and aerial laser scanning. This study determines the DOV using the EGM2008 model and gravity data in Sweden. The impact of the DOVs on horizontal and vertical coordinates, considering different flight altitudes and camera field of view, is assessed. The results confirm that the calculated DOV components using the EGM2008 model are sufficiently accurate for aerial mapping system purposes except for mountainous areas because the topographic signal is not modelled correctly.

Direct georeferencing of airborne mobile mapping systems is developing with unprecedented speed using GNSS/INSintegration. Removal of systematic errors is required for achieving a high accurate georeferenced product in mobile mappingplatforms with integrated GNSS/INS sensors. It is crucial to consider the deflection of verticals (DOV) in direct georeferencing dueto the recently improved INS sensor accuracy. This study determines the DOV using Sweden’s EGM2008 model and gravity data.The influence of the DOVs on horizontal and vertical coordinates and considering different flight heights is assessed. The resultsconfirm that the calculated DOV components using the EGM2008 model are sufficiently accurate for aerial photogrammetrypurposes except for the mountainous areas because the topographic signal is not modeled correctly.

What are the key challenges in establishing precise geodetic control networks? This is one of the most important tasks of geodesists and land surveyors, since geodetic control networks are essential for the deformation and environmental monitoring of dams, tunnels, high towers, landslides and bridges, among others. This article discusses the main challenges relating to vertical angles and provides some recommendations for how they can be overcome.

Determination of the Earth’s gravity field and geopotential value is one of the fundamental topics in physical geodesy. Traditional terrestrial gravity and precise leveling measurements can be used to determine the geopotential values at a local or regional scale. However, recent developments in optical atomic clocks have not only rapidly improved fundamental science but also contributed to applied research. The latest generation of optical clocks is approaching the accuracy level of 10−18 when facilitating atomic clock networks. These systems allow examining fundamental theories and many research applications, such as atomic clocks applications in relativistic geodesy, to precisely determine the Earth’s gravity field parameters (e.g., geopotential values). According to the theory of relativistic geodesy, the frequency difference measured by an optical clock network is related to the gravity potential anomaly, provided that the effects of disturbing signals (i.e., tidal and non-tidal contributions) are filtered out. The relativistic geodesy principle could be used for a practical realization of global geodetic infrastructure, most importantly, a vertical datum unification or realization of height systems. This paper aims to review the background of relativistic (clock-based) geodesy and study the variations of optical atomic clock measurements (e.g., due to hydrology loading and land motion).

In classical two-dimensional (2D) geodetic networks, reducing slope distances to horizontal ones is an important task for engineers. These horizontal distances along with horizontal directions are used in 2D geodetic adjustment. The common practice for this reduction is the use of vertical angles to reduce distances using trigonometric rules. However, one faces systematic effects when using vertical angles. These effects are mainly due to refraction, deflection of the vertical (DOV), and the geometric effect of the reference surface (sphere or ellipsoid). To mitigate refraction and DOV effects, one can choose to observe the vertical angles reciprocally if the baseline points’ elevation difference is small. This paper quantifies these effects and proposes a proper solution to eliminate the effects in small-scale geodetic networks (where the longest distances are less than 5 km). The goal is to calculate slope distances into horizontal ones appropriately. For this purpose, we used the SWEN17_RH2000 quasigeoid model (in Sweden) to study the impact of the DOV applying different baseline lengths, azimuths, and vertical angles. Finally, we propose an approach to study the impact of the geometric effect on vertical angles. We illustrate that the DOV and the geometric effects on vertical angles measured reciprocally are significant if the height difference of the start point and endpoint in the baseline is large. Geometric correction should be considered for the measured vertical angles to calculate horizontal distances correctly if the network points are not on the same elevation, even if the vertical angles are measured reciprocally.