A Sketch-based Language for Representing Uncertainty in the Locations of Origin of Herbarium Specimens

Uncertainty fields have been suggested as an appropriate model for retrospective georeferencing of herbarium specimens. Previous work has focused only on automated data capture methods, but techniques for manual data specification may be able to harness human spatial cognition skills to quickly interpret complex spatial propositions. This paper develops a formal modeling language by which location uncertainty fields can be derived from manually sketched features. The language consists of low-level specification of critical probability isolines from which a surface can be uniquely derived, and high-level specification of features and predicates from which low-level isolines can be derived. In a case study, five specimens of Kolsteletzkya pentacarpos housed in the Ted Bradley Herbarium at George Mason University are retrospectively georeferenced, and locational uncertainties of error distance, possibility region and uncertainty field representations are compared

A Sketch-based Language for Representing Uncertainty in the Locations of Origin of Herbarium Specimens

Uncertainty fields have been suggested as an appropriate model for retrospective georeferencing of herbarium specimens. Previous work has focused only on automated data capture methods, but techniques for manual data specification may be able to harness human spatial cognition skills to quickly interpret complex spatial propositions. This paper develops a formal modeling language by which location uncertainty fields can be derived from manually sketched features. The language consists of low-level specification of critical probability isolines from which a surface can be uniquely derived, and high-level specification of features and predicates from which low-level isolines can be derived. In a case study, five specimens of Kolsteletzkya pentacarpos housed in the Ted Bradley Herbarium at George Mason University are retrospectively georeferenced, and locational uncertainties of error distance, possibility region and uncertainty field representations are compared

Terrain Surface Modeling Using Triangular Spline Patches

Algorithms and software for digital terrain modeling using TIN based surface model are presented in the paper. Processing of all types of terrain surface data are supported: mass points, local extrema, contours, breaklines, structure lines, fault lines, etc. TIN topology and Bézier triangular surface patches are used for terrain surface reconstruction. Special attention is dedicated to the problem of respecting all implicit information about terrain surface that are contained within the input data. This is especially important in cases when terrain surface has to be reconstructed by using mostly contour data, since there are a lot of additional information that are implicitly contained within the data of this type. The software also contains functions for efficient verification of collected terrain data and DTM. Special consideration is given to the numerical procedures and algorithms aiming at providing contours and other outputs of DTM analysis of cartographic quality as required by many surveyors and their clients. The results of experiments demonstrated that the quality of terrain surface reconstruction from contours and/or other data using developed procedures and software is better, or at least as good as the quality achieved by using procedures and methods implemented within standard GIS/DTM software

Beyond the epsilon band: polygonal modeling of gradation/uncertainty in area-class maps

A spatial modeling technique is proposed to represent boundary uncertainty or gradation on area-class maps using a simple polygon tessellation with designated zones of indeterminacy or transition zones. The transition zone can be conceptualized as a dual of the epsilon band, but is more flexible and allows for a wide range of polygonal configurations, including polygons with sinuous boundaries, spurs, three-way transition zones, and null polygons. The model is specified using the medial axis to capture the general shape characteristics of a transition zone. Graph theoretic representation of an extended version of the medial axis captures key junctions in both shape and classification and is used to identify well-formed transition zones that can be logically and unambiguously handled by the model. A multivariate classification surface is specified by first defining degrees or probabilities of membership at every point on the medial axis and transition zone boundary. Degrees or probabilities of membership at all other points are defined by linear interpolation. The technique is illustrated with an example of a complex transition zone, and a simple isoline representation that can be derived from the model is presented. The proposed modeling technique promises to facilitate expert characterization of soil formations, ecological systems, and other types of areal units where gradation and/or boundary uncertainty are prevalent

2.5D-GIS und Geobasisdaten : Integration von Höheninformation und digitalen Situationsmodellen

[no abstract

Geodetic infrastructure of Serbia

Geodetic reference systems and their realization at the territory of Serbia have been created and maintained since the end of 19th century. Until mid-80s a series of reference geodetic networks were established: trigonometric networks in four orders, two levelling networks of high accuracybut also a series of gravimetric networks. In the following period of 20 years, there were not any organized worksaiming to maintenance of existing networks and creating new ones. In 1996, works started again on developing a new geodetic infrastructure in the form of realizing: a passive geodetic network, a network of permanent stations (AGROS – the active geodetic reference network of Serbia) as well as basic gravimetric networks. In this paperwork, a short review of works aiming to establish and use said networks is given but also a series of suggestions for a future development of geodetic infrastructure of Serbia