Importing large GADM vector data: Difference between revisions
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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 | '''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.