[GRASS-user] how to use r.mapcalc in GRASS

[marion-brunet]

<span style="font-family:arial,helvetica,sans-serif; font-size:12px">Hello,<br>
<br>
I am trying to calculate the difference between two raster layers. For that, I am using GRASS in QGIS. I use the command r.mapcalc. In the field "expression to evaluate" I wrote </span><br>
<code><span style="font-size:12px"><span style="font-family:arial,helvetica,sans-serif">r.mapcalc expression=diff =TIN_12_17-TIN_06_18</span></span><br>
<span style="font-size:12px"><span style="font-family:arial,helvetica,sans-serif">TIN_12_17 and TIN_06_18 are the names of my two rasters.<br>
I then select the region on my canevas.<br>
When I click "run" I don't have any error but no file is created in my project. I would like to have a new raster file with the difference of the two previous ones.<br>
<br>
What am I doing wrong?<br>
<br>
Thank you,<br>
Marion</span></span></code>
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