[GRASS-user] Import / mapset problem

[Glynn Clements]

Koen Hufkens wrote:

> I've got some issues with importing data into a mapset.
> 
> I have been working on data that I imported into GRASS without any  
> problems up until today. I noticed that although I import everything  
> into a x, y lattice with no geospatial reference data some of my  
> recent files get other parameters and do not align with my previous  
> ones.
> 
> All maps are tiff files with the same x, y size and should align  
> perfectly however some have mapunits 2.4 (m? could be possible as this  
> is roughly the spatial resolution of the image) others have mapunits  
> 1. Futhermore, the older data seems to have been in some kind of  
> projection as the cursor values display not the expected x y range  
> corresponding to the number of pixels in the image. I suspect that  
> this difference is the cause of my problems.
> 
> However, I do use r.in.gdal with the overwrite protection settings so  
> normally everything should have been imported without spatial  
> reference data that could be embedded in the (geo)tiff header, or am I  
> mistaken.
> 
> Any ideas why my first files still have some spatial reference data  
> embedded even after explicitly saying not to use them at import? Any  
> solutions to get rid of unwanted geotiff headers?

If GDALGetGeoTransform() reports a grid->spatial transformation for
the data, it will use those parameters instead of the default settings
of south=west=0, res=1.

This is distinct from -o switch, which disables the check that the
source uses the same SRS (ellipse, datum, projection type, projection
parameters), and cannot be disabled. If you want to force the default
south=west=0, res=1 regardless, you need to subsequently "fix" the
imported map with r.support.

-- 
Glynn Clements <glynn at gclements.plus.com>