School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.
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Transcript of School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.
![Page 1: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/1.jpg)
School of GeographyFACULTY OF ENVIRONMENT
Point-surface interpolation
![Page 2: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/2.jpg)
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
![Page 3: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/3.jpg)
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
1W. R. Tobler, (1970) "A computer movie simulating urban growth in the Detroit region". Economic Geography, 46(2): 234-240.
![Page 4: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/4.jpg)
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
![Page 5: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/5.jpg)
Common methods
• Thiessen polygons
• Gradual or abrupt?
• Exact or approximate?
• Local or global?
• Deterministic or stochastic?
![Page 6: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/6.jpg)
Common methods
• Trend surfaces
• Gradual or abrupt?
• Exact or approximate?
• Local or global?
• Deterministic or stochastic?
![Page 7: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/7.jpg)
Common methods
![Page 8: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/8.jpg)
Common methods
• Inverse Distance Weighting (IDW)
• Gradual or abrupt?
• Exact or approximate?
• Local or global?
• Deterministic or stochastic?
![Page 9: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/9.jpg)
Common methods
• Triangulated Irregular Networks (TINs)
• Gradual or abrupt?
• Exact or approximate?
• Local or global?
• Deterministic or stochastic?
![Page 10: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/10.jpg)
Geostatistical analyst
• Geostatistical analyst in ArcMap
![Page 11: School of Geography FACULTY OF ENVIRONMENT Point-surface interpolation.](https://reader035.fdocuments.us/reader035/viewer/2022062417/551ad7a255034606048b544c/html5/thumbnails/11.jpg)
Practical exercise
Hands-on Exercise #2Interpolating point data in ArcGIS