[GRASS-user] Debugging a r.gdal import error

[Markus Metz]

On Tue, Sep 24, 2019 at 12:34 AM Rich Shepard <rshepard at appl-ecosys.com>
wrote:
>
> On Mon, 23 Sep 2019, Markus Neteler wrote:
>
> > Well, without error message nor link to the data it is hard to say.
> > In addition, it is usually worthwhile to check a dataset with gdalinfo.
>
> Markus,
>
> I'm dealing with two separate issues: r.in.gdal/r.import unable to read
> hdr.adf and maps that are supposed to fit tightly to the border of a topo
> quad rectangle don't. I'll deal with the latter issue first.
>
> I separated the orginal bare-earth dataset for one portion of the topo
quad
> and uploaded it to fileconvory.com
> <
http://www.fileconvoy.com/dfl.php?id=g180d8982ad7f3f731000197000c9cb9624a57ea50a
>.
> Even xz compressed it's 550MB large. It will be available at that URL for
5
> days.

I used r.in.gdal in=be_45123h5 out=be_45123h5, i.e. the coverage directory
as input (GDAL recognizes this as an AIG/Arc/Info Binary Grid).

The output appears slightly tilted (rotated clockwise), but this is
apparently correct: the data match other elevation data. The topo quad
rectangle is probably a guide whereabouts the DEM should be located. If in
doubt you need to supply the corresponding topo rectangle for testing,
without any modification of course.

The DEM as it is imported into GRASS seems correct. Any rotation will
introduce errors.

Markus M

>
> The output of gdalinfo -proj4 on the w* file is the same as that in the
> prj.adf file.
>
> My workflow started with creating a new location using the prj.adf file to
> set the projection. Then I applied r.in.gdal to the hdr.adf. Displaying
the
> imported file shows it is slightly rotated clockwise (see attached file
> h5clatsop.png). The other two maps in this topo quad import and display
> correctly (the three can be seen in the attached file,
45123a5_clatsop.png.
>
> I'm at a loss to understand why the imported map is not square with the
topo
> boundary. The gdalinfo -proj4 results (attached) show different
coordinates
> for the northwest and southwest but the OLC data coordinator tells me the
> map displays correctly for him and one of his colleagues.
>
> Regards,
>
> Rich_______________________________________________
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