combining map data of similar dimension to produce new maps using algebraic operations

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1answer
75 views

Map algebra from files in multiple directories

I'm a rookie in python programming. I want to do map algebra for multiple rasters but these rasters are in different folders. Here's the code ive created so far: #Importing modules import arcpy from ...
4
votes
0answers
56 views

Vector to raster, then map algebra

I have a table of polygons representing travel time isochrones on particular days. For each origin point, there are five isochrone geometries (stored in separate rows). For each origin point, I want ...
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vote
0answers
49 views

How to compute the ls factor equation for USLE model in qgis grass r.mapcalc

To compute the LS factor for the USLE model, the following equation easily works in ArcGIS. How can I perform the same in QGIS under GRASS r.mapcalc? LSfator = Power (("flowaccNW") * ...
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0answers
143 views

Map Algebra in VB.NET Add-In Tool

I'm trying to run a map algebra expression in a vb.net add-in, and can't seem to get it to work. It's a roving window that interpolates noData areas in a DEM. The expression works in the Python ...
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0answers
33 views

How to speed up raster/map algebra in PostGIS?

I am testing map algebra with PostGIS (2.1 with PostgreSQL 9.3) on two images, and found it to be rather slow. For example, dividing two images of 7200 * 3600 pixels took 110 ~ 120s on a desktop with ...