GEOG281 Lecture Notes - Lecture 7: Terrset, Satellite Imagery, Thematic Mapper

• School: University of Waterloo
• Department: Geography and Environmental Management
• Course: GEOG281
• Professor: Su Yin Tan

Document Summary

The raster model divides the geographic area into a regular grid of cells in speciic sequence. Convenional sequence is row by row from the top let corner. Space-illing every locaion corresponds to a cell in the raster. Regular tessellaion (division of space) that can be conceptualised as a matrix- like series of cells. Grid origin usually cell in upper let corner. Grid resoluion minimum linear dimension of the smallest unit of geographic space sampled. Atributes are explicit: oten only a single atribute is assigned to a cell, otherwise, a key" ideniier in each cell links to related database iles containing muliple atributes for each grid cell. Choose raster cell size 1/2 the length (1/4 the area) of smallest feature to map. Set data type (integer, real: overlay grid over study area. Store co-ordinates of nw corner and grid resoluion (assumes north orientaion) How to input raster data into a gis: manual raster coding, raster scanning.