[GRASS-user] Importing USGS' wrs2_descending Shapefile

[Markus Metz]

On Wed, Jan 14, 2015 at 12:37 PM, Nikos Alexandris
<nik at nikosalexandris.net> wrote:
> Nikos Alexandris:
>
>>>> I can't get wrs2_descending.shp file (from
>>>> <http://landsat.usgs.gov/documents/wrs2_descending.zip>) to import
>>>> sans errors (grass7).  No matter the snap threshold.  Anyone recently
>>>> imported it?
>
>
> Markus Neteler wrote:
>
>> I think that their overlapping areas cannot be represented as pure
>> topological model.
>
>
> Right.

Yes, overlapping areas can be represented as a topological model
through M:N mapping: each area can belong to several categories,
several areas can have the same category. If you want to get the
coverage for a particular Landsat scene, just select the path and row
with where="PATH = x and row = y". See also the manual of v.buffer for
a similar example.

>
>> Hence, you need to maintain them (AFAIK it is the -c option in v.in.ogr).
>> Please correct me if I am wrong.
>
For this shapefile, original polygons can not be maintained (incorrect
boundaries, centroids exceeding number of areas).

Markus M

>
> I'll do so.
>
>> The question is: what's you scope? Visualization?
>
>
> A complete set of tools for Landsat data, inside GRASS, requires a proper
> trimming utility.  The existing add-on  i.landsat.trim  does not satisfy my
> needs.
>
> Using a slightly modified version of
> <ttps://github.com/robintw/LatLongToWRS>,  which I'll integrate into (my
> yet-unifinished personal mini-project) <i.landsat.wrs2trim>, one will simply
> need to tell which landsat scene(s) (or, optionally, the desired path & row
> combination(s)) should be border-pixel-trimmed.
>
> I've decided to go the hardway, meaning, let the user or the script, get the
> "wrs2_descending.shp" file, import it in GRASS and let the module do its
> work.  Or, perhaps, share along with the module a clean vector data set (in
> GRASS' native format? compressed?).
>
> Nikos
>
> _______________________________________________
> grass-user mailing list
> grass-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-user