Difference between revisions of "Importing large GADM vector data"

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(Created page with "'''Q:''' How do I import very large data in GRASS? I.e. from [http://www.gadm.org/ GADM] <br\> '''A:''' In contrast to GADM v1, GADM v2 contains a lot of floating point repres...")
 
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'''Q:''' How do I import very large data in GRASS? I.e. from [http://www.gadm.org/ GADM] <br\>
'''Q:''' How do I import very large data in GRASS? I.e. from [http://www.gadm.org/ GADM] <br\>
'''A:''' In contrast to GADM v1, GADM v2 contains a lot of floating point representation errors in the coordinates, most probably created by the software used to create GADM v2. You need to perform additional cleaning with snapping to a very small threshold, i.e. v.in.ogr snap=1e-7. And you should use GRASS 7 for the import of large vector data, because the import may not work with GRASS 6.
'''A:''' In contrast to GADM v1, GADM v2 contains a lot of floating point representation errors in the coordinates, most probably created by the software used to create GADM v2. You need to perform additional cleaning with snapping to a very small threshold, i.e.  
 
v.in.ogr snap=1e-7
 
And you should use GRASS 7 for the import of large vector data, because the import may not work with GRASS 6.




[[Category:FAQ]]
[[Category:FAQ]]
[[Category: massive data analysis]]
[[Category: massive data analysis]]

Revision as of 12:46, 11 February 2013

Q: How do I import very large data in GRASS? I.e. from GADM <br\> A: In contrast to GADM v1, GADM v2 contains a lot of floating point representation errors in the coordinates, most probably created by the software used to create GADM v2. You need to perform additional cleaning with snapping to a very small threshold, i.e.

v.in.ogr snap=1e-7

And you should use GRASS 7 for the import of large vector data, because the import may not work with GRASS 6.