[GRASS-user] Raster boxplots selection

GRASS GRASS user
1

Dear coummunity

I am wondering if my code for selecting specific raster points (e.g. squares, Quadrate) has a bug. I do not want to plot all squares, because I still have not yet data for all squares.

v.extract quadrat out=quadrat_3 where=“ID_Quadrat=527190 and ID_Quadrat=569228 and ID_Quadrat=581166” --o

The resason is that I get an error on the next line

v.to.rast quadrat_3 out=quadrat_3 use=attr attribute_column=ID_Quadrat --o

ERROR: Database connection not defined for layer <1>

Full Code:

r.import input=allema_LZall_UAA_pres_merged.tif output=al_pres --o

g.region -ap rast=al_pres

v.import input=untersuchungsquadrate_2020_2024.gpkg output=quadrat --o

v.info -g quadrat

v.extract quadrat out=quadrat_3 where=“ID_Quadrat=527190 and ID_Quadrat=569228 and ID_Quadrat=581166” --o

v.to.rast quadrat_3 out=quadrat_3 use=attr attribute_column=ID_Quadrat --o

r.boxplot -o input=al_pres zones=quadrat_3 output=“al_pres_boxplot_3.png” raster_statistics=median –o

Thanks a lot

Sibylle

2

On Wed, Aug 7, 2024 at 11:00 AM sibylle via grass-user <grass-user@lists.osgeo.org> wrote:

Dear coummunity

I am wondering if my code for selecting specific raster points (e.g. squares, Quadrate) has a bug. I do not want to plot all squares, because I still have not yet data for all squares.

v.extract quadrat out=quadrat_3 where=“ID_Quadrat=527190 and ID_Quadrat=569228 and ID_Quadrat=581166” --o

The where statement will result in no quadrats selected. Use ‘or’ instead of ‘and’:

v.extract quadrat out=quadrat_3 where=“ID_Quadrat=527190 or ID_Quadrat=569228 or ID_Quadrat=581166” --o

This will give you the three quadrats (or the quadrats that have those IDs, in case there are more quadrats with the same ID).

The resason is that I get an error on the next line

v.to.rast quadrat_3 out=quadrat_3 use=attr attribute_column=ID_Quadrat --o

ERROR: Database connection not defined for layer <1>

Full Code:

r.import input=allema_LZall_UAA_pres_merged.tif output=al_pres --o

g.region -ap rast=al_pres

v.import input=untersuchungsquadrate_2020_2024.gpkg output=quadrat --o

v.info -g quadrat

v.extract quadrat out=quadrat_3 where=“ID_Quadrat=527190 and ID_Quadrat=569228 and ID_Quadrat=581166” --o

v.to.rast quadrat_3 out=quadrat_3 use=attr attribute_column=ID_Quadrat --o

r.boxplot -o input=al_pres zones=quadrat_3 output=“al_pres_boxplot_3.png” raster_statistics=median –o

Thanks a lot

Sibylle

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