Questions tagged [r.mapcalc]

raster map calculator that performs arithmetic on raster map layers

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Running parallel r.mapcalc in GRASS

I have thousands raster maps (3652, named raster_name.1, raster_name.2,... raster_name.x,... raster_name.3652) and for each map I want to do the r.mapcalc-threshold operation below here: ...
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2answers
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GRASS r.mapcalc to replace null values

Is there a way to use r.mapcalc to replace null with 0? I tried if(isnull(map1), 0) but that produces a map that is entirely 0. I need only cells containing null to be altered!
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2answers
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Multiply cell values during r.mapcalc in GRASS

I'm doing some sieve mapping in GRASS. I have several map layers containing various values representing site suitability ranks. I need to use r.mapcalc to add these maps together for example map1 + ...
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1answer
229 views

r.mapcalculator

I am using QGIS 2.18.25. I'm struggling to use r.mapcalc to calculate the ndvi for a workbook project. R.mapcalculator is shown on the workbook I'm using and seems simpler to use. Is there a plug-in ...
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2answers
77 views

Purpose of comma in r.mapcalc in GRASS GIS 7.4

I would like to know the purpose of a comma in r.mapcalc of GRASS GIS. Consider this example - r.mapcalc "noise = if(landuse96_28m==1 || landuse96_28m==2, roads_buffers, null())" In the above ...
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2answers
215 views

Converting 0 values to 1 in QGIS 3 using r.mapcalc GUI

I'm using GRASS 7.4.1 in QGIS 3.2 and would like to change 0 values of a slope raster to 1. I've been following this video tutorial and my r.mapcalc function looks exactly the same. However the output ...