THE THIRD THE THIRD DIMENSION FOR DIMENSION FOR
CADASTRECADASTRE
PETR KUBICEK, MASARYK UNIVERSITY, LABGISBRNO, CZ
WHY 3D???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
• Comprehensive, useful and economically
competitive description - WHATWHAT is possible to
describe and HOWHOW to do it.
• Terrain analysis still missing a general formal
theory - usually descriptive and fuzzy
• Describe the terrain - analysis reasoning process
from different viewpointsdifferent viewpoints (geomorphologic, civil
engineering, landscape ecological)
PRAGMATIC REASONSPRAGMATIC REASONS
DATA SOURCESDATA 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-2 100 m resolution, mean altitude, 3-15 m accu., 10sq km distribution (10 000 pixels)
GEOMORPHOMETRYGEOMORPHOMETRY
Morphological description of terrain and surfaces in generalSpecific geomorphometry - landforms definition and abstraction to measure their size, shape, and relation to each otherGeneral 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 dependentDescription 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 STATISTICSSUMMARY STATISTICS
Summary statistics of local surface derivatives better characterise complex areas (cadastre, region, county..)Software packages for statistical analysisTesting and parameterisation “a set of measurements that describe topographic form well enough to distinguish topographically disparate landscapes" (Pike, 1988).
Terrainattributes
Mean Standard deviation Skewness Kurtosis
Altitude LEVEL RELIEF MASSIVENESS HOMOGENEITY
SlopeGradient
STEEPNESS HETEROGENEITY LIMITATION MODALITY
Evans 1998, simplified
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 dataLandSerf - http://www.geog.le.ac.uk/jwo/research/LandSerf/index.html
PARAMETRIC AND PHYSIOGRAPHIC PARAMETRIC AND PHYSIOGRAPHIC SYSTEMS OF TERRAIN EVALUATIONSYSTEMS 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 theseclasses at pragmatic(thematic) critical values -“isopleths”more statistically reliablePhysiographic (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
GENERALIZATIONGENERALIZATION
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 unchangednumerical (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..)
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)
DISCUSSIONDISCUSSION
• SurveySurvey 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..)
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