I'm using QGIS 3.14.3 with GRASS 7.6.1 and trying to add together the values for 3 raster layers using r.series as I'm told this handles no data values better than raster calculator. Please see log below as r.series is only returning no data values.
Processing algorithm…
Algorithm 'r.series' starting…
Input parameters:
{ '-n' : True, 'GRASS_RASTER_FORMAT_META' : '', 'GRASS_RASTER_FORMAT_OPT' : '', 'GRASS_REGION_CELLSIZE_PARAMETER' : 0, 'GRASS_REGION_PARAMETER' : '332966.7752,400122.2567,344713.3291999999,567742.8156 [EPSG:27700]',
'input' : ['C:/.../Bowland_Hazard.tif','C:/.../Bowland_Vulnerability.tif','C:/.../Bowland_Waterways_Classified.tif'], 'method' : [10],
'output' : 'C:/Users/seansuzedielois/AppData/Local/Temp/processing_6bed28472c854ab889990fbc4a475879/c70921be43984837baaa5faad3656e83/output.tif', 'quantile' : '', 'range' : [0,0], 'weights' : '' }
g.proj -c proj4="+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs"
r.external input="C:\...\Bowland_Hazard.tif" band=1 output="rast_5dd7bc9666a9616" --overwrite -o
r.external input="C:\...\Bowland_Vulnerability.tif" band=1 output="rast_5dd7bc9666a9617" --overwrite -o
r.external input="C:\...\Bowland_Waterways_Classified.tif" band=1 output="rast_5dd7bc9666a9618" --overwrite -o
g.region n=567742.8156 s=344713.3291999999 e=400122.2567 w=332966.7752 res=30.0
r.series input=rast_5dd7bc9666a9616,rast_5dd7bc9666a9617,rast_5dd7bc9666a9618 -n method="sum" range="0,0" output=output7e2b59a143804b069736ec560da663f5 --overwrite
g.region raster=output7e2b59a143804b069736ec560da663f5
r.out.gdal -t -m input="output7e2b59a143804b069736ec560da663f5" output="C:\Users\seansuzedielois\AppData\Local\Temp\processing_6bed28472c854ab889990fbc4a475879\c70921be43984837baaa5faad3656e83\output.tif" format="GTiff" createopt="TFW=YES,COMPRESS=LZW" --overwrite
Starting GRASS GIS...
WARNING: Concurrent mapset locking is not supported on Windows
Cleaning up temporary files...
Executing <C:\Users\seansuzedielois\AppData\Local\Temp\processing_6bed28472c854ab889990fbc4a475879\grassdata\grass_batch_job.cmd> ...
C:\Users\seansuzedielois\Documents>chcp 1252 1>NUL
C:\Users\seansuzedielois\Documents>g.proj -c proj4="+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs"
WARNING: Datum <Unknown_based_on_Airy_1830_ellipsoid> not recognised by GRASS and no parameters found
Default region was updated to the new projection, but if you have multiple mapsets `g.region -d` should be run in each to update the region from the default
Projection information updated
C:\Users\seansuzedielois\Documents>r.external input="C:\...\Bowland_Hazard.tif" band=1 output="rast_5dd7bc9666a9616" --overwrite -o
Over-riding projection check
Reading band 1 of 1...
Link to raster map <rast_5dd7bc9666a9616> created.
C:\Users\seansuzedielois\Documents>r.external input="C:\...\Bowland_Vulnerability.tif" band=1 output="rast_5dd7bc9666a9617" --overwrite -o
Over-riding projection check
Reading band 1 of 1...
Link to raster map <rast_5dd7bc9666a9617> created.
C:\Users\seansuzedielois\Documents>r.external input="C:\...\Bowland_Waterways_Classified.tif" band=1 output="rast_5dd7bc9666a9618" --overwrite -o
Over-riding projection check
Reading band 1 of 1...
Link to raster map <rast_5dd7bc9666a9618> created.
C:\Users\seansuzedielois\Documents>g.region n=567742.8156 s=344713.3291999999 e=400122.2567 w=332966.7752 res=30.0
C:\Users\seansuzedielois\Documents>r.series input=rast_5dd7bc9666a9616,rast_5dd7bc9666a9617,rast_5dd7bc9666a9618 -n method="sum" range="0,0" output=output7e2b59a143804b069736ec560da663f5 --overwrite
0..3..6..9..12..15..18..21..24..27..30..33..36..39..42..45..48..51..54..57..60..63..66..69..72..75..78..81..84..87..90..93..96..99..100
C:\Users\seansuzedielois\Documents>g.region raster=output7e2b59a143804b069736ec560da663f5
C:\Users\seansuzedielois\Documents>r.out.gdal -t -m input="output7e2b59a143804b069736ec560da663f5" output="C:\Users\seansuzedielois\AppData\Local\Temp\processing_6bed28472c854ab889990fbc4a475879\c70921be43984837baaa5faad3656e83\output.tif" format="GTiff" createopt="TFW=YES,COMPRESS=LZW" --overwrite
ERROR 6: SetColorTable() only supported for Byte or UInt16 bands in TIFF format.
Checking GDAL data type and nodata value...
2..5..8..11..14..17..20..23..26..29..32..35..38..41..44..47..50..53..56..59..62..65..68..71..74..77..80..83..86..89..92..95..98..100
Using GDAL data type <Float64>
Input raster map contains cells with NULL-value (no-data). The value -1.#IND will be used to represent no-data values in the input map. You can specify a nodata value with the nodata option.
Exporting raster data to GTiff format...
2..5..8..11..14..17..20..23..26..29..32..35..38..41..44..47..50..53..56..59..62..65..68..71..74..77..80..83..86..89..92..95..98..100
r.out.gdal complete. File <C:\Users\seansuzedielois\AppData\Local\Temp\processing_6bed28472c854ab889990fbc4a475879\c70921be43984837baaa5faad3656e83\output.tif> created.
C:\Users\seansuzedielois\Documents>exit
Execution of <C:\Users\seansuzedielois\AppData\Local\Temp\processing_6bed28472c854ab889990fbc4a475879\grassdata\grass_batch_job.cmd> finished.
Cleaning up temporary files...
Execution completed in 5.61 seconds
Results:
{'output': <QgsProcessingOutputLayerDefinition {'sink':C:/Users/seansuzedielois/AppData/Local/Temp/processing_6bed28472c854ab889990fbc4a475879/c70921be43984837baaa5faad3656e83/output.tif, 'createOptions': {'fileEncoding': 'System'}}>}
Loading resulting layers
Algorithm 'r.series' finished