[GRASS-user] howto make my srtm-dem jump the GIS gap

David Finlayson david.p.finlayson at gmail.com
Wed Aug 9 12:16:13 EDT 2006


That is a good point. The 2 Gb limit is still a problem for file-based data
in ArcGIS. Rudolf, is your file around 2 Gb?

Try exporting a small region. If that fails, can you post your failing file
to the web where we can take a look at it?

David


On 8/9/06, William Kyngesburye <woklist at kyngchaos.com> wrote:
>
> On Aug 9, 2006, at 4:51 AM, Rudolf Maurer wrote:
>
> > Will try William and Macieks r.out.gdal suggestions, but did not do
> > it yet.
> > When I export TIF I am losing the height data, right?
> >
> That's why you use the Int16 data type, so it can store the full
> range of elevations.  So it only works for integer elevations.
> Floats would need another method, like the ascii grid export from
> GDAL.  Or scaling the data up a number of decimal places so an
> integer could be used.
>
> > I spotted an online document on SRTM-Data which mentioned the
> > direct import of SRTM-Data using the Spatial Analyst extension.
> > Do I need this for importing the GRASS-made Grid-Files, too?
> >
> I don't think the Spatial Analyst extension has anything to do with
> raster conversion, just extra analysis functions.
>
> > 2006/8/8, David Finlayson < david.p.finlayson at gmail.com>:
> > I use r.our.arc frequenctly to transfer data between ArcGIS and
> > GRASS. What exactly is the problem you are having?
> >
>
> When I think back on it, I believe the reason I had no luck with
> ascii/arc grid export is that I needed to transfer HUGE rasters over
> to Arc, and Arc choked on the multi-GB text files.  I think an ascii
> grid under 2GB could work.  There's a lot of expansion in a text
> file, so the grass raster size limit would be smaller.
>
> And, it might not have even been such a hard limitation, more a
> matter of principal - I just didn't want to copy a multi-GB file over
> the network when there must be a better binary way, and zipping,
> copying, unzipping a huge file doesn't save much time.
>
> -----
> William Kyngesburye <kyngchaos at kyngchaos.com>
> http://www.kyngchaos.com/
>
> All generalizations are dangerous, even this one.
>
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>



-- 
David Finlayson
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