GGR272H1 Lecture Notes - Lecture 9: Voronoi Diagram, Lookup Table, Associative Entity
Document Summary
June 8: lecture 9 - distance and overlay. How buffers are created: e. g. line - software will draw circle of radius x around ends of line and connect with lines. Isoline: line of equal value from line segment. E. g. noise pollution around highways, protected zones around lakes and rivers. E. g. enhanced points of interest - query grocery stores - perform buffer on grocery stores: end up with blue circles around grocery stores (could also dissolve the boundaries between circles) High park digitized into sub-polygons - need to merge: dissolve internal boundaries and then measure distances from parks > 0. 5 sq km. Spatial query: select by location: e. g. grocery stores and subway stations select grocery stores within 1000 m of subway stations. Vector - binary (inside buffer or outside), raster - continuous (distance from feature) Raster distance - euclidian distance (measured from cell centre to cell centre) For multiple points: distance = value in cell (distance from closest cell)
