Presentation on theme: "School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation."— Presentation transcript:
School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation
Day 1: point-surface interpolation Principles Tobler’s First Law of Geography and spatial interpolation Classification of methods Common methods Thiessen polygons Trend surfaces Inverse distance weighting (IDW) TINs Geostatistical Analyst in ArcMap
Principles of interpolation Tobler’s First Law of Geography “Everything is related to everything else, but near things are more related than distant things.” 1 Spatial interpolation The procedure of estimating the values of properties at unsampled sites within an area covered by existing observations important in addressing problem of data availability quick fix for partial data coverage interpolation of point data to raster surface role of filling in the gaps between observations 1 W. R. Tobler, (1970) "A computer movie simulating urban growth in the Detroit region". Economic Geography, 46(2): 234-240.
Classification of methods Methods of spatial interpolation: many different methods available e.g. Thiessen polygons e.g. Inverse distance weighting classification according to: exact or approximate deterministic or stochastic local or global gradual or abrupt Remember! Tobler’s First Law of Geography
Common methods Thiessen polygons Gradual or abrupt? Exact or approximate? Local or global? Deterministic or stochastic?
Common methods Trend surfaces Gradual or abrupt? Exact or approximate? Local or global? Deterministic or stochastic?