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

ALTITUDE

AMPLITUDE

TYPOLOGYTYPOLOGY

LEGEND ENTRYLEGEND ENTRYLandform typology+geologyLandform typology+geology

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..)

3X3 65X65

3x33x3 7x77x7

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..)

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