Upload
clifford-todd
View
232
Download
3
Tags:
Embed Size (px)
Citation preview
Digital terrain analyses –DEM principles
DEM data structure
• Lines – contour map
• Raster – altitude matrix
• Vector – TIN/Triangular irregular network
• Vector – TRN/Triangular regular network
Digital terrain analyses –DEM principles
TRN – Tringular regular network
• fast, scale-independent DEM
Digital terrain analyses –DEM principles
DEM structure advantages/disadvantages
LINES
• ”Hydrologically” correct, best representation, dynamic and flexible
• Limited analyse possibility
• Limited visualisation
Digital terrain analyses –DEM principles
DEM structure advantages/disadvantages
Altitude matrix
• Easy analyses and modelling
• Redundancy
• Rigid data structure, resolution
• Limited adaption to topographic structures
Digital terrain analyses –DEM principles
DEM structure advantages/disadvantages
TIN
• Complicated data structure
• Limited analyse possibility
• Very good terrain representation
• Good for visualisation, resolution independant
Digital terrain analyses –DEM principles
DEM generation and assessment
• Sampling – data source
• Interpolation
• Quality assessment
• Visualisation
Digital terrain analyses –DEM principles
Data sources
• Single points – spread (geodesy, photogrammetry)
• Single points – regular (direct measurements by plane or satellite (LIDAR), digital photogrammetry)
• Contours
• Aim: Interpolate points in a regular grid or corner points of triangles INTERPOLATION
Digital terrain analyses –DEM principles
DEM generation and assessment
• Sampling
• Interpolation
• Quality assessment
• Visualisation