[GRASS-user] GRASS7.4 TGRASS parse error while mapcalc computatio

Martin Landa landa.martin at gmail.com
Wed Feb 21 04:21:56 PST 2018


2018-02-21 12:57 GMT+01:00 Anika Bettge <bettge at mundialis.de>:
> I use TGRASS to calculate a NDVI.

btw, recently I was doing something similar in Jena GRASS GIS workshop, see [1].

> GRASS 7.4.0 (accra32630):~ > t.rast.mapcalc input=b4,b8 output=test1
> expression="test1 = float(b8 + b4)" basename=test1  --overwrite
> Starting temporal sampling...
> Starting mapcalc computation...
> Ung├╝ltige Karte
> <S2_0e76f09b_d221_4e88_b7f9_d3S2_0e76f09b_d221_4e88_b7f9_d3b8aad4975d_20180102T140217_B08_10maad4975d_20180102T140217_B04_10m>
> Parse error
> FEHLER: parse error
> ERROR: Error while mapcalc computation

It seems like your input strds are broken. Try to check all maps
registered in input b4 and b8 datasets (by t.rast.list).
t.rast.mapcalc tries to read non-existing raster map
in your case.


[1] http://training.gismentors.eu/grass-gis-workshop-jena-2018/units/21.html#ndvi-st-computation

Martin Landa

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