GEOB 270 Lecture Notes - Lecture 12: Voronoi Diagram, Edge Detection, Geomorphology
25 Dec 2016
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Used identify trends/patterns and outliers: compute local vs global statistics, simplification (smoothing, exaggeration (increase differences, hot/cold spots (identify local outliers) Smoothened image (pixel values avg. within a moving window) Edge detection (pixel values within moving window given min/max. Vector: value: hotspot analysis , many options under spatial statistics toolbox: Example: disease rates: with vector, neighborhood is defined using topology. Secondary surfaces: compute slope and aspect from dem"s. Viewshed analysis: military, cell phone towers, fire towers, visual impacts of. Uses: geomorphology(slope stability, road construction costs, hiking trails/ski runs, legislation logging practices. Uses: snow pack/ water runoff, vegetation growth, agricultural model. Thiessen polygons: dividing up points into polygons, create a map. Or strictly looking at points next to each other: exact or approximate, gradual or abrupt, deterministic or stochastic. Raster approaches: easy to implement (assume all layers can be matched grid size, orientation, map algebra, boolean operations through map algebra. Vector approaches: more geometrically complex, requires topology to be reconstructed.
