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During spatial decision making, the quality of the utilized data is of high importance. During navigation these decisions are crucial for being routed to the desired destination (usually going by the shortest or fastest route). Road networks, the main data source for routing, are prone to changes which can have a big impact on the computed route and therefore on travel time. For instance, routes computed using an outdated street network can result in longer travel times, in longer distance, as well in cases where the desired destination might not be anymore reachable via the computed route. Data from OpenStreetMap with different timestamps allows us to download road network snapshots from different years, i.e., from 2014 to 2020. On each of those datasets the fastest route between 500 randomly chosen point pairs in Vienna, Austria, was computed. These routes were also reconstructed on the most recent dataset for evaluation reasons. The resulting travel times, travel length as well as feasibility of the route were compared with the most recent dataset. The results provide a first assessment of temporal quality based on the currentness of a dataset.

A problem with 3D models is that devices used to display them are typically two-dimensional, i.e., computer monitors or printed maps. User interfaces of computer software are based on mouse, touchscreen, keyboards, etc. and are optimized for this dimensionality. However, this causes problems when working with 3D models and the user must adapt her actions by interpreting the missing third dimension. While this might not necessarily pose a problem for frequent users, infrequent users may find this quite challenging. Holographic models, on the other hand, float in front of the user, providing a 3D perspective. Interaction with this kind of models may thus be more intuitive than traditional interaction. In the paper we present the results from a first user test. 15 participants tested interaction with a holographic model visualized using Augmented Reality (AR) technology. The results were compared to those of 15 participants using a traditional 3D-CAD. It was found that the holographic approach is more intuitive leading to a lower frustration level although it is still restricted by technical limitations.

The main aim of this paper is to document the gradual evolution of cadastral maps and associated land books in the area of today’s Austria as well as the more dramatic development of the cadastral ...

he paper focuses on approaches to the registration of real property rights in the case of underground or subwaytunnels in different EU countries: Austria, Bulgaria, Czech Republic, Croatia, Greece, Poland, Slovenia, andSweden. The authors conducted analysis on the registration of rights to subway tunnels in the chosen countries,including its effectiveness in ensuring appropriate property rights to construct and exploit tunnels. Special at-tention was given to limitations related to the lack of legal provisions vertically dividing space, i.e. into layers,and referring to the ownership right to the layers. Benefits which might be achieved by the introduction of a 3Dreal property subdivision were pointed out. The analysis of the available data concerning the geometry ofsubway tunnels in particular countries was presented. The authors tried to answer the question whether theaccessible data concerning the geometry of subway tunnels allows to generate a 3D geospatial model of aconstructed object, and to specify the space which should be determined as a 3D parcel in the 3D real propertycadastre, for the purpose of registering property rights for the object (the tunne The paper focuses on approaches to the registration of real property rights in the case of underground or subway tunnels in different EU countries: Austria, Bulgaria, Czech Republic, Croatia, Greece, Poland, Slovenia, and Sweden. The authors conducted analysis on the registration of rights to subway tunnels in the chosen countries, including its effectiveness in ensuring appropriate property rights to construct and exploit tunnels. Special attention was given to limitations related to the lack of legal provisions vertically dividing space, i.e. into layers, and referring to the ownership right to the layers. Benefits which might be achieved by the introduction of a 3D real property subdivision were pointed out. The analysis of the available data concerning the geometry of subway tunnels in particular countries was presented. The authors tried to answer the question whether the accessible data concerning the geometry of subway tunnels allows to generate a 3D geospatial model of a constructed object, and to specify the space which should be determined as a 3D parcel in the 3D real property cadastre, for the purpose of registering property rights for the object (the tunnel).

Andrew U. Frank retired in October 2016 after a scientific career of 38 years with positions in Switzerland, Maine and Austria. One of the main applications that he constantly referred to and that he analysed in detail was land administration. This review article tries to give an overview of Frank’s work in the context of land administration and how he influenced the approach to land administration research. He organized his work mainly in four pillars: technical, legal, organizational and economical aspects. Each of them is discussed in the paper and the influence on international cooperation is shown.

Human self-localisation is an important part of everyday life. In order to determine one’s own position and orientation, the allocentric representation, usually in the form of a map, has to be aligned with one’s own egocentric representation of the real world. This requires objects (anchor points) that are present in both representations. We present two novel approaches that aim to simplify the process of alignment and thus the self-localisation. The Viewshed approach is based on visibility analysis and the Image Recognition approach identifies objects and highlights them on the map. On the basis of an empirical experiment with 30 participants in the city of Vienna, Austria, the two approaches were compared with each other as well as with a standard approach using a 2D map representation. The goal is to assess and compare aspects like efficiency, user experience, and cognitive workload. Results show that the Image Recognition method provided the best support and was also most popular among users. The Viewshed method performed well below expectations.

Today the surveying profession is very different from what it was twenty years ago. Recent technological innovations, globalization, and global land-related challenges have allowed a wide range of advances in the surveying profession. The vision is to promote surveying practices that can enhance the quality of services in a variety of tracks in the land profession. According to the new adjacent professional areas and the needs of the labor market, academic courses for surveyors have to be adapted to meet the broader scope of the surveying profession and to supply highly qualified land professionals. This paper outlines the new challenges for the surveying profession and highlights the core skills, competencies, and knowledge that should be highly valued to produce competent experts. Furthermore, this paper suggests a common structure of a surveying curriculum to capture the new academic themes for better adaptation to the broader scope of the surveying profession.

Geodetic survey data are typically analysed using the assumption that measurement errors can be modelled as noise. The least squares method models noise with the normal distribution and is based on the assumption that it selects measurements with the highest probability value (Ghilani, 2010, p. 179f). There are environment situations where no clear maximum for a measurement can be detected. This can happen, for example, if surveys take place in foggy conditions causing diffusion of light signals. This presents a problem for automated systems because the standard assumption of the least squares method does not hold. A measurement system trying to return a crisp value will produce an arbitrary value that lies within the area of maximum value. However repeating the measurement is unlikely to create a value following a normal distribution, which happens if measurement errors can be modelled as noise. In this article we describe a laboratory experiment that reproduces conditions similar to a foggy situation and present measurement data gathered from this setup. Furthermore we propose methods based on fuzzy set theory to evaluate the data from our measurement.

The paper focuses onapproaches to the registration of real property rights in the case of underground or subway tunnels in different EU countries: Austria, Bulgaria, Czech Republic, Croatia, Greece, Poland, Slovenia, and Sweden. The Authors made analysis of the current way of registration of rights to subway tunnels in the chosen countries, including its effectiveness in ensuring appropriate property rights to construct and exploit tunnels. A special attention was given to limitations related to the lack of the possibility to vertically divide the space, i.e. to divide the space into layers, and to refer the ownership right to the layers. Benefits which might be achieved by the introduction of a 3D real property cadastre were pointed out. The analysis of available data concerning the geometry of subway tunnels in particular countries was presented. The authors tried to answer the question whether the accessible data concerning the geometry of subway tunnels allows to generate a 3D geospatial model of a constructed object, and to specify the space which should be determined as a 3D parcel in the 3D real property cadastre, for the purpose of registering property rights for the object (the tunnel).

This study analyzes urban expansion and the peri-urban land tenure security situation in Amhara National Regional State of Ethiopia, taking Bahir Dar and Debre Markos as case studies. To detect the extent of urban expansion, data from Landsat satellite images were analyzed using ERDAS IMAGINE, ENVI, and ArcGIS segmentation, classification, and mapping tools. The land tenure security situation was assessed through interviews with local farmers. Analysis shows high rates of spatial urban expansion, but stagnating levels of property registration and certification among peri-urban landholders, affecting their feelings of land tenure security. Though Ethiopia's efforts to impart land tenure security by implementing low-cost land registration programs in rural areas are promising, the programs in peri-urban areas are underdeveloped, and these areas are subject to expropriation due to urban expansion. Policies for more sensitive growth are needed in rapidly developing places like these.

The objective of this discussion is the Austrian land cadastre, which forms the basis of the Austrian land information system, together with the land registry. From a data structure perspective, the Austrian land cadastre is a traditional parcel-oriented system and includes a geometric description of land plots linked to other records describing the nature of the land plots. The changeable institutional (legal) framework was shaped the continuous development of the Austrian land cadastre since the first systematic land survey and cadastral mapping at the beginning of the 19th century. With the progress of information technology in recent decades, it has been developed into a contemporary land information system, which (together with the land registry) provides up-to-date land information. It has to be emphasized that the current land cadastre still contains some data from its very beginning and, for this reason, the historical development of this evidence, including data sources, is of great importance for users of these data. The first part of the article provides an introduction to the historical development of the Austrian land cadastre, followed by the presentation of contents and procedures of the current land cadastre.

Three-dimensional (3D) cadastral systems can only be built if there are suitable height reference systems. However, the earth is neither homogeneous nor flat, and the plumb lines are curved and not parallel. Thus, the definition of height and the implementation of geodetic height systems are complex. 3D cadastres must connect to the existing national height reference. In addition, cadastral systems are designed to persist for centuries. Over such long periods, the earth changes, from plate tectonics, erosion, human intervention, etc. Changes in the technology of measurement equipment can also occur, allowing different definitions. These considerations are important in the design of a 3D cadastre. At minimum, the height system used for the cadastre must be well-defined, to enable adjustments from potential changes in the height system or even the actual point heights. This study examines existing height systems and the determination of height in the context of cadastral tasks. Accuracy requirements for height in a 3D cadastre are analyzed using typical examples. The selected height system must support these requirements. This study also develops the questions that must be answered and highlights the problems that can emerge in some of the solutions. There is no height reference system that fits all needs, and each solution has advantages and disadvantages. Different systems may be optimal for different countries. It may also be beneficial to allow different geometrical qualities for different parts of a country.

Since the use of volunteered geographic information (VGI) or crowd sourced data (Goodchild, 2007) became more common, several people proposed the use of such methods of data collection for various fields. Success stories were Wikipedia encyclopaedia and OpenStreetMap (OSM), but also using VGI in land administration has been proposed. Robin McLaren proposed crowd sourcing as a way to get a new citizen collaboration model in land administration to enhance transparency and decrease costs (McLaren, 2011). Keenja et al. discussed the perception of VGI within the Dutch cadastre (Keenja, De Vries, Bennet, & Laarakker, 2012). Basiouka and Potsiou even discuss how crowd sourcing can be used to identify errors in the Hellenic cadastre (Basiouka & Potsiou, 2012). One problem of VGI is the quality control (compare Goodchild & Li, 2012). The problem with most data in a land administration system is that there is only a small group of people that can verify the correctness of information. The correct location of a boundary, for example, can only be assessed by the owners of the pieces of land touching at the boundary (and surveyors after investigation and measurement). How shall VGI then provide reliable data? Boundaries between areas of different use may be visible but land administration is often interested in ownership boundaries. In the paper we discuss the types of data used in land administration as discussed by Dale and McLaughlin (1999). These categories are then analyzed to identify the areas where VGI can actually provide reliable input. What we hope to learn from such an analysis is how to use the methodology of crowd sourcing for land administration, even if the data collection authoritatively.

Three-dimensional (3D) cadastral systems can only be built if there are suitable height reference systems. However, the earth is neither homogeneous nor flat, and the plumb lines are curved and not parallel. Thus, the definition of height and the implementation of geodetic height systems are complex. 3D cadastres must connect to the existing national height reference. In addition, cadastral systems are designed to persist for centuries. Over such long periods, the earth changes, from plate tectonics, erosion, human intervention, etc. Changes in the technology of measurement equipment can also occur, allowing different definitions. These considerations are important in the design of a 3D cadastre. At minimum, the height system used for the cadastre must be well-defined, to enable adjustments from potential changes in the height system or even the actual point heights. This study examines existing height systems and the determination of height in the context of cadastral tasks. Accuracy requirements for height in a 3D cadastre are analyzed using typical examples. The selected height system must support these requirements. This study also develops the questions that must be answered and highlights the problems that can emerge in some of the solutions. There is no height reference system that fits all needs, and each solution has advantages and disadvantages. Different systems may be optimal for different countries. It may also be beneficial to allow different geometrical qualities for different parts of a country.

Das Wissen um marktnahe Liegenschaftswerte sowie deren räumliche und zeitliche Referenz ist als allgemeine Infrastruktur im öffentlichen Interesse zu sehen, die ebenso zum volkswirtschaftlichen Kapitalstock gerechnet werden kann, wie die räumlichen Informationen über Liegenschaftsobjekte (Kataster) und den damit verknüpften Rechten (Grundbuch und öffentlich-rechtliche Eigentumsbeschränkungen). Die bisher in Teilen Europas angewendeten Einheitswertverfahren als einfache Methoden der Wertermittlung werden zunehmend in Frage gestellt, und in vielen Ländern gibt es bereits flächendeckend funktionierende Systeme zur Ermittlung von marktnahen Werten. Diese Systeme, welche u. a. für die Bemessung der Grundsteuer herangezogen werden, beruhen auf vorhandenen Geodaten. Im Artikel werden die in Österreich für eine Massenwertbestimmung möglichen und flächendeckend verfügbaren Geodaten vorgestellt und der Nutzen einer damit gewonnenen neuen Bewertungsinfrastruktur diskutiert.

A natural language interface can improve human-computer interaction with Geographic Information Systems (GIS). A prerequisite for this is the mapping of natural language expressions onto spatial queries. Previous mapping approaches, using, for example, fuzzy sets, failed because of the flexible and context-dependent use of spatial terms. Context changes the interpretation drastically. For example, the spatial relation “near” can be mapped onto distances ranging anywhere from kilometers to centimeters. We present a context-enriched semiotic triangle that allows us to distinguish between multiple interpretations. As formalization we introduce the notation of contextualized concepts that is tied to one context. One concept inherits multiple contextualized concepts such that multiple interpretations can be distinguished. The interpretation for one contextualized concept corresponds to the intention of the spatial term, and is used as input for a spatial query. To demonstrate our computational model, a next generation GIS is envisioned that maps the spatial relation “near” to spatial queries differently according to the influencing context.

In a Gauss–Markov Model (GMM) with fixed constraints, all the relevant estimators perfectly satisfy these constraints. As soon as they become stochastic, most estimators are allowed to satisfy them only approximately, thereby leaving room for nonvanishing residuals to describe the deviation from the prior information. Sometimes, however, linear estimators may be preferred that are able to perfectly reproduce the prior information in form of stochastic constraints, including their variances and covariances. As typical example may be considered the case where a geodetic network ought to be densified without changing the higher-order point coordinates that are usually introduced together with their variances and (some) covariances. Traditional estimators are based on the “Helmert” or “S-transformation,” respectively an adaptation of the fixed-constraints Least-Squares estimator. Here we show that neither approach generates the optimal reproducing estimator, which will be presented in detail and compared with...

Optimal paths in networks are determined by costs attached to nodes and edges. However, these costs are uncertain. The question raised in this paper is how to determine the effect that this uncertainty has on the optimal path, i.e., the spatial distribution of the optimal path. The method used is Monte Carlo Simulation. The simulation was done for the road network of Vienna. Travel time serves a cost function and the temporal distribution of travel time is derived from floating car data. The experiment shows that typically several different paths are possible with similar travel times.

A cadastre is a system of major importance for economy and planning. A cadastre provides data on land. It is the basis for legal aspects like ownership as well as fiscal aspects like taxation of land. The cadastre also provides data for planning assignments (for example, boundaries of constructions, land use, and soil). Storage and update of these data require a complex system that had been developed in Austria during more than 100 years. Understanding, using, and improving a cadastre requires knowledge on the cadastral processes. The problems a cadastre must solve are important to understand the needs for a cadastre. It is also important to understand the processes of a cadastre to see how a cadastre works. These processes define the way a cadastre handles data and what prerequisites the data must fulfil to be accepted by the cadastre. Improving a system requires analysis of the processes. The user wants to work with a cadastre. He needs processes that meet his demands. Improving the efficiency of the processes, therefore, improves the efficiency of the cadastre directly because then the user will be satisfied (his work will be done better or faster). The paper discusses the tasks of a cadastre. The starting point is the needs of users (owners, government and many others). The needs define the tasks and the data needed to fulfil the tasks. The next step is the definition of the processes to fulfil the tasks. The paper then formalizes these processes. Finally, implementations for two different cadastral systems prove the general validity of the processes.

GNSS receivers are an essential part of modern technological devices. Mobile phones, digital cameras, and car navigational systems are only some examples for tools using GNSS technology. These sensors can be used to support other tasks as well. A simple example is fleet management where the car navigation systems can provide data on the current position, intended target and selected route of the vehicles. However, utilizing data requires information on its quality, in this case on the positional accuracy of the sensors. This quality was checked for GNSS receivers in different mobile phones and a tracking device. Tracking of vehicles is usually restricted to a navigational network. In many cases, several lines may be in parallel with small lateral distance, e.g., lanes on a street, parallel streets, or parallel rail tracks. In these cases, the lateral quality is of higher importance than the longitudinal quality. Thus we concentrated on this aspect of the quality.

D city models represent existing physical objects and their topological and functional relations. In everyday life the rights and responsibilities connected to these objects, primarily legally defined rights and obligations but also other socially and culturally established rights, are of importance. The rights and obligations are defined in various laws and it is often difficult to identify the rules applicable for a certain case. The existing 2D cadastres show civil law rights and obligations and plans to extend them to provide information about public law restrictions for land use are in several countries under way. It is tempting to design extensions to the 3D city models to provide information about legal rights in 3D. The paper analyses the different types of information that are needed to reduce conflicts and to facilitate decisions about land use. We identify the role 3D city models augmented with planning information in 3D can play, but do not advocate a general conversion from 2D to 3D for the legal cadastre. Space is not anisotropic and the up/down dimension is practically very different from the two dimensional plane - this difference must be respected when designing spatial information systems. The conclusions are: (1) continue the current regime for ownership of apartments, which is not ownership of a 3D volume, but co-ownership of a building with exclusive use of some rooms; such exclusive use rights could be shown in a 3D city model; (2) ownership of 3D volumes for complex and unusual building situations can be reported in a 3D city model, but are not required everywhere; (3) indicate restrictions for land use and building in 3D city models, with links to the legal sources.

Section I: Philosophical background and Semantics.- Ontology, Epistemology, Teleology: Triangulating Geographic Information Science.- Geonoemata Elicited: Concepts, Objects, and Other Uncertain Geographic Things.- Virtue Ethics for GIS Professionals.- Why Is Scale an Effective Descriptor for Data Quality? The Physical and Ontological Rationale for Imprecision and Level of Detail.- Semantic Engineering.- Section II: Mathematical Methods.- A Common Spatial Model for GIS.- Computation with Imprecise Probabilities.- Spatial Data Quality: Problems and Prospects.- Latent Analysis as a Potential Method for Integrating Spatial Data Concepts.- Stereology for Multitemporal Images with an Application to Flooding.- Modeling Spatiotemporal Paths for Single Moving Objects.- Moving Objects in Databases and GIS: State-of-the-Art and Open Problems.- The Degree Distribution of Random Planar Graphs.- Section III: Tools and Applications.- Geographical Information Engineering in the 21 Century.- Towards Visual Summaries of Geographic Databases Based on Chorems.- Intelligent Spatial Communication.- Training Games and GIS.- Cadastre and Economic Development.

Geospatial information systems (GIS) have been applied in modeling environmental and ecological systems. 3D Moving objects are spatiotemporal objects whose location and/or extent change over time, and they are among those recent evolutions that emerged to fulfill some of the new requirements for GI community. Many of the earlier works were based on the assumption that exact trajectory information was available (or could be obtained) at every time instant. Unfortunately, this assumption cannot be guaranteed in real applications where trajectory information is associated inherently with uncertainty and lack of complete and precise knowledge. In this paper, we explore how a trajectory is influenced by uncertainty. Then we study the nature of 3D moving object trajectories in the presence of uncertainty and we introduce two data models for uncertain trajectories that are used to represent moving objects. By using this model in a case study, we obtain the most probable answer where we consider a 3D moving object path under uncertain conditions and lack of knowledge.

Virtual worlds, and especially the Internet, become increasingly important for advertisement, planning purposes, and simulation. Concepts that proved useful in the real world have been transferred to the Internet. A frequently seen example is the concept of navigation processes. In the real world such processes are based on the properties of space. A transfer to the virtual reality of the Internet is only useful if the properties of real space and virtual space are similar. In this paper we present different concepts of space and discuss their suitability for the Internet.

The book is a standard textbook on least squares adjustment for surveying students. It was originally written by Paul R.Wolf in the early 1980s. Now the fifth edition is available, authored for by ...

3D city models are getting more important as a field of research and business and received an increasing amount of attention from both the scientific community and the professional field. 3D city models are one of the new tools for sustainable city development. Since development questions occur repeatedly, the used city models should be maintainable, i.e. the system should be kept up-to-date and not be created new for each decision. This is a challenge. Creating a model representing the current status of a city has been addressed in research literature. The major challenge is the vast amount of data to be collected, processed and visualised. However, keeping the resulting model up-to-date has not been discussed yet. Updating requires the introduction of a suitable concept of time in the model. This would then allow representing historic and current status of the city as well as future scenarios. Processes provide the connection between different points in time. Processes also change the appearance of the city and need to be represented in the model for change detection. In this paper, we discuss the challenges and show necessary properties for city models and systems maintaining them to reach a reasonable level of maintainability.

The article presents a conceptual framework for computations with imprecise values. Typically, the treatment of imprecise values differs from the treatment of precise values. While precise computations use a single number to characterize a value, computations with imprecise values must deal with several numbers for each value. This results in significant changes in the program code because values are represented, e.g., by expectation and standard deviation and both values must be considered within the computations. It would be desirable to have a solution where only limited changes in very specific places of the code are necessary. The mathematical concept of lifting may lead to such a solution.