[gdal-dev] How to find image footprints instead of envelopes?

[Sean Gillies]

Jukka,

Yes, I've written the Python script to do this. If you're willing to
install Rasterio (which is GDAL and underneath, but new bindings and not
osgeo.gdal) you can use its rio-shapes command (based on GDAL's
polygonizer):

https://github.com/mapbox/rasterio/blob/master/docs/cli.rst#shapes

The script's entry point is at
https://github.com/mapbox/rasterio/blob/master/rasterio/rio/features.py#L197.
You're welcome to port it to GDAL's Python bindings; swapping out rasterio
and swapping in osgeo.gdal wouldn't be terribly hard.


On Tue, Oct 13, 2015 at 5:19 AM, Jukka Rahkonen <
jukka.rahkonen at maanmittauslaitos.fi> wrote:

> Hi,
>
> This question appears every now and then in the gis.stackexchange and I
> have
> been wondering about it by myself as well: How to generate a footprint
> polygon of the real image data area so that the possible nodata areas would
> not be included?
>
> I have been thinking that I could convert the original image into a new
> image with alpha channel or a one-bit image with nodata=0 and yesdata=1 and
> then polygonize the alpha band or the 1-bit image with gdal_polygonize.py.
> I
> guess that it would work but it feels a bit complicated. Is there any more
> direct way for doing this task with GDAL? I bet that at least someone has
> written a python script for it because the need is so obvious.
>
> -Jukka Rahkonen-
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev




-- 
Sean Gillies
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20151014/1e34e612/attachment.html>