[GRASS-user] GRASS Location covering multiple UTM zones and SpatiaLite

[Markus Metz]

On Tue, Mar 28, 2017 at 10:32 AM, Blumentrath, Stefan <
Stefan.Blumentrath at nina.no> wrote:
>
> Hi Bülent,
>
>
>
> GRASS 7 uses SQLite for attribute management by default, so except for
the spatial part the DB backend it is identical. And a couple of modules
can handle points without topology.

Note that SQLite is not SpatiaLite. SpatiaLite is a format for spatial
vector data, like e.g. shapefile, kml, or GRASS native vector format. If
you want to do vector processing in GRASS, it is recommended to import
external vector data into GRASS, do the processing, and export the results
to SpatiaLite. SQLite is the default database backend in GRASS 7 for vector
attributes, but SQLite and SpatiaLite are two different things.

Markus M

>
> If you give us more information on what exactly you are planning to do
with your vector data it would be more easy to suggest a solution… E.g. are
you using polygons as input or output? What are you going to do with them…
>
> BTW. it should be fully possible to load GRASS data in QGIS 2.18. What is
your OS and GRASS version and what is the “path” issue you mentioned?
>
>
>
> Cheers
>
> Stefan
>
>
>
>
>
>
>
> From: Bulent Arikan [mailto:bulent.arikan at gmail.com]
> Sent: tirsdag 28. mars 2017 09.37
> To: Blumentrath, Stefan <Stefan.Blumentrath at nina.no>
> Subject: Re: [GRASS-user] GRASS Location covering multiple UTM zones and
SpatiaLite
>
>
>
> Hi Stefan,
>
>
>
> Thank you for your response! I guess that makes sense and I will define a
location for UTM 36 since it covers the majority of the region as well as
it is between 35 and 37. That would probably help to keep any distortion at
minimum.
>
>
>
> I understand that there is still not full compatibility with SpatiaLite,
so I will probably think something else.
>
>
>
> Cheers,
>
>
>
> BÜLENT ARIKAN
>
> Assistant Professor
>
> Department of Ecology and Evolution
>
> Eurasia Institute of Earth Sciences
> Istanbul Technical University
> Maslak-Sarıyer
> Istanbul
> 34469
>
> Turkey
>
> http://web.itu.edu.tr/~bulentarikan/index.html
>
>
>
> On Mar 28, 2017, at 10:07 AM, Blumentrath, Stefan <
Stefan.Blumentrath at nina.no> wrote:
>
>
>
> Hi Bülent,
>
>
>
> Here in Norway we face the same situation. The country covers UTM zones
31 to 36. However, the standard the public authorities suggest is to use
the average (UTM 33) when running analysis on the whole country.
>
> Of course this leads to imprecision and distortion, but if that is
significant or not depends on your application (esp. scale of the problem
you are going to solve)…
>
>
>
> Since GRASS has a topological vector format, linking external vector data
can cause issues in your analysis, esp. with polygons. However, points can
be fine in many cases… Please have a look at the mauals of v.external [1]
and v.external.out [2].
>
>
>
> Cheers,
>
> Stefan
>
>
>
> 1: https://grass.osgeo.org/grass72/manuals/v.external.html
>
> 2: https://grass.osgeo.org/grass72/manuals/v.external.out.html
>
>
>
>
> _______________________________________________
> grass-user mailing list
> grass-user at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/grass-user
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-user/attachments/20170328/f191136b/attachment.html>