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

[Blumentrath, Stefan]

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.
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
[cid:image001.jpg at 01D2A7AA.458E7A90]

On Mar 28, 2017, at 10:07 AM, Blumentrath, Stefan <Stefan.Blumentrath at nina.no<mailto: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

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