[gdal-dev] using gdal_viewshed

[Tamas Szekeres]

I've recently fixed the implementation in my local version causing a
similar issue (RasterIO error when writing target raster), where the given
maxdistance setting would produce an empty row at the top or the bottom of
the result image.
I'll prepare a fix in gdal in the next few days and let us see if that
fixes this issue as well.

Best regards,

Tamas


Eli Adam <eadam at co.lincoln.or.us> ezt írta (időpont: 2019. nov. 12., K,
22:26):

> Hi Ben,
>
> On Sun, Nov 10, 2019 at 3:57 AM Ben Avrahami <avrahami.ben at gmail.com>
> wrote:
> >
> > Hello all, I've been trying trying to use the newest gdal_viewshed in
> gdal-dev release, and I've run into an error I can't quite understand.
> >
> > The input I've been using is:
> >
> >     gdal_viewshed -md 1000 -ox "691868.511" -oy "3492031.487" <input
> tiff> <output tiff>
>
> It might be helpful to copy and paste your command so if there are
> typos or otherwise, they can be spotted.
>
> A gdalinfo report on your input file could also be helpful.  That
> would show coordinates of the image and allow looking at things like
> are those coordinates within the image?  Is it in the coordinate
> system of the image?  A gdalinfo report details that nicely.
>
> >
> > And I get the response:
> >
> >     ERROR 5: C:\temp\files\out.tif, band 1: Access window out of range
> in RasterIO().  Requested
> >     (0,-1) of size 67x1 on raster of 67x67.
> >     ERROR 1: RasterIO error when writing target raster
>
> This makes it seem like something isn't lining up correctly.  With the
> absence of information some random guess include: that the coordinate
> is not within the image, or perhaps the coordinate is less than -md
> 1000 units from the edge (although testing that on other data here
> worked fine), that there are pixel alignment/resolution issues and
> using coordinates not to three decimal places would work better.
>
> I see that gdal_viewshed -md 900 -ox 985710 -oy 658590
> http://download.osgeo.org/gdal/data/aaigrid/095b_dem_90m.asc
> output2.tif works
>
> and
>
> gdal_viewshed -md 800 -ox 985710 -oy 658590
> http://download.osgeo.org/gdal/data/aaigrid/095b_dem_90m.asc
> output3.tif fails with the error:
>
> 0ERROR 5: output3.tif, band 1: Access window out of range in
> RasterIO().  Requested
> (0,-1) of size 19x1 on raster of 19x19.
> ERROR 1: RasterIO error when writing target raster
>
> it seems that -md must be a multiple of the resolution.
>
> Best regards, Eli
>
> >
> > I get a similar error if I try to use the GDALViewshedGenerate C-API
> function. The input us a valid WGS84-UTM tiff file, and the output is a
> valid path, but the file does not actually exist until I run the command.
> After I run the command, the output file is created but only filled
> halfway. Any help at wall would be appreciated.
> >
> > regards, Ben
> > _______________________________________________
> > gdal-dev mailing list
> > gdal-dev at lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/gdal-dev
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20191112/2915ce2a/attachment.html>