[GRASS-dev] Satellite tiles: tiles missing after import?

[Markus Metz]

On Thu, Dec 22, 2016 at 3:25 PM, Markus Neteler <neteler at osgeo.org> wrote:
>
> Hi,
>
> I imported both the WRS2 Landsat tiles [1] as well as the Sentinel-2
> KML [2] (giving extra issues during import + also querying due to
> quoting issues).
>
> In both cases, when zooming into the map, some polygons are not drawn
> in areas where the tiles massively overlap.
>
> I used the -c flag of v.in.ogr to not break the polygons but to keep
> them intact.

The -c flag is problematic: it does not break polygons, but polygons are
converted to GRASS boundaries. Centroids have to be calculated for each
output GRASS area. As a result, an output GRASS area corresponding to an
input polygon might have multiple centroids or no centroid at all (these
are the holes you see).

Please do not use the -c flag with v.in.ogr unless you know exactly what
you are doing and what you will get.

Markus M

>
> Is that a GUI issue or a vector engine issue?
>
> [1] https://landsat.usgs.gov/pathrow-shapefiles --> wrs2_descending.zip
> [2]
https://sentinel.esa.int/documents/247904/1955685/S2A_OPER_GIP_TILPAR_MPC__20151209T095117_V20150622T000000_21000101T000000_B00.kml
>
> thanks,
> Markus
> _______________________________________________
> grass-dev mailing list
> grass-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-dev/attachments/20161222/f5d0bcd2/attachment.html>