THE THIRD DIMENSION FOR CADASTRE PETR KUBICEK, MASARYK UNIVERSITY, LABGIS BRNO, CZ

WHY 3D??? ABDS for CEEC (Administrative Boundary Data Services for Central and Easter European Countries) Cadastre boundary data geometry, generalisation rules, and descriptive attributes Work package in the first phase of the project – the evaluation and verification of possible 3D characteristics for cadastre

WHAT HOW Comprehensive, useful and economically competitive description - WHAT is possible to describe and HOW to do it. Terrain analysis still missing a general formal theory - usually descriptive and fuzzy different viewpoints Describe the terrain - analysis reasoning process from different viewpoints (geomorphologic, civil engineering, landscape ecological) PRAGMATIC REASONS

DATA SOURCES Key issue for further processing and description Terrain representation - grid, TIN, contour lines Appropriate for statistical modelling Available Easy to use and generalise Different grid mesh size, tested for geomorphometric consistency ( Evans 1974,98 ) Czech Example: DMR-1 1km resolution,S-42, max.altitude, 30m accu., DMR m resolution, mean altitude, 3-15 m accu., 10sq km distribution ( pixels)

GEOMORPHOMETRY Morphological description of terrain and surfaces in general Specific geomorphometry - landforms definition and abstraction to measure their size, shape, and relation to each other General geomorphometry - analysis of (land )surface as a continuous, rough surface, described by the attributes at a sample points or areas (windows). More objective, sampling pattern resolution dependent Description at point - altitude and surface derivatives, i.e. Slope (gradient + aspect) Curvature (profile + plan) Fundamental to general geomorphometry, form a coherent system for (land) surface description and analysis

SUMMARY STATISTICS Summary statistics of local surface derivatives better characterise complex areas (cadastre, region, county..) Software packages for statistical analysis Testing and parameterisation “a set of measurements that describe topographic form well enough to distinguish topographically disparate landscapes" (Pike, 1988).

SUMMARY STATISTICS SUMMARY STATISTICS - continue Three basic classes of measures : point (3x3) window (3x3 -??)window (3x3 -??) drainage basin - natural landscape unit Software packages for statistical analysis of 3D terrain data LandSerf -

PARAMETRIC AND PHYSIOGRAPHIC SYSTEMS OF TERRAIN EVALUATION Parametric land (terrain) classification – subdivision of land on the basis of selected attribute values, for each attribute - an array of numerical values. processe give tables, histograms, graphs, maps, or a combination of these classes at pragmatic(thematic) critical values -“isopleths” more statistically reliable Physiographic (landscape) land classification scheme is based on the natural classification or terrain by recognising natural units, mapping them, and then measuring their properties - based on genetic geomorphic approach - scale dependant, empirical and descriptive

ALTITUDE AMPLITUDE

TYPOLOGY LEGEND ENTRY Landform typology+geology

GENERALIZATION Grid resolution of digital elevation data influences: spatial pattern frequency distribution of derived topographic attributes (slope, curvature, specific catchment area) Raster-mode generalisation (McMaster and Monmonier 1989, Muller 1991) :  structural – modification of the number of cell while the shape remains unchanged  numerical (spatial filtering, convolution) – reduces the complexity of an image image (smoothing, sharpening)  numerical categorisation (image classification) – reduction from ratio level to nominal level  categorical – spatial operations (merging, aggregation..)

3X3 65X65

3x37x7

GENERALIZATION GENERALIZATION - continue Weibel (1991) - automated terrain generalisation - amplified intelligence approach – an interactive system incorporating the human knowledge into generalisation system. Based on extraction of structure lines (ridges, channels) from the original terrain surface and formation of Structure Line Model (SLM). Level of detail is controlled by the user Human operator initiates a line generalisation process A generalised surface model is reconstructed from the generalised SLM (generalised in vector linear format)

DISCUSSION Survey Survey over nation-wide digital terrain (3D) data sets, make a comparison (grid mesh, acquisition method, licensing policy, data quality and accuracy, maintenance and updating..) and possibly integration Legibility Legibility of description - regardless the criticism, appropriate categorisation, verbal description for better understanding of end users Correlation with other data sourcesCorrelation with other data sources - economic valuation of terrain data,”functional delimitation” of relief (morphometric/morphologic characteristics and combination of their suitability for distinctive human activities - recreation, agriculture..)

Functional delimitation of relief for agricultural activities - Slovakia (Mazur 1988)