Hi list,
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?
Kind regards,
Koen
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@gclements.plus.com>