Importing large GADM vector data: Difference between revisions

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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 into GRASS GIS? I.e. from [http://www.gadm.org/ GADM]
'''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 the older GADM v1, GADM v2 contains a lot of ''floating point representation errors'' in the coordinates, most probably caused by the software used to create GADM v2. You need to perform additional cleaning with snapping to a very small threshold, i.e.  


And you should use GRASS 7 for the import of large vector data, because the import may not work with GRASS 6.
v.in.ogr ... snap=1e-7
 
Important: You should use the improved [http://grass.osgeo.org/download/software/ GRASS GIS 7] for the import of large vector data, because the import may not work with GRASS GIS 6.




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

Revision as of 12:53, 11 February 2013

Q: How do I import very large data into GRASS GIS? I.e. from GADM

A: In contrast to the older GADM v1, GADM v2 contains a lot of floating point representation errors in the coordinates, most probably caused 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

Important: You should use the improved GRASS GIS 7 for the import of large vector data, because the import may not work with GRASS GIS 6.

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