[GRASS-user] Rotate raster map?

[Rich Shepard]

On Tue, 24 Sep 2019, Rich Shepard wrote:

>> https://grass.osgeo.org/grass78/manuals/r.in.gdal.html#error-messages
>> "... the image must be first externally rotated, applying the rotation
>> info stored in the metadata field of the raster image file. For
>> example, the gdalwarp software can be used to transform the map to
>> North-up (note, there are several gdalwarp parameters to select the
>> resampling algorithm):
>> 
>> gdalwarp rotated.tif northup.tif
>> "
>
> Ah, I don't recall seeing this. I'll read it more closely and futz with
> gdalwarp to fix this class of problems. Then I'll focus on why r.in.gdal
> fails to read the hdr.adf files on some maps.

I've read the gdalwarp page and the wikipage to which it links and am still
unsure of how to apply gdalwarp.

The directory with the raw bare earth files contains dblbnd.adf,
metadata.xml, sta.adf, w001001x.adf, hdr.adf, prj.adf, w001001.adf. Which
file should be passed to gdalwarp?

I assume the -wo (warp option) is what I want and I'll specify lanczos.

Presuming the output of gdalwarp is to be re-directed to a file, what format
extension should be used? The input, I believe, is in ArcGrid format and if
gdalwarp is passsed a single file name in that directory what is the output
format.

Thanks in advance,

Rich