Vector Overlapping Areas - Revision history

Neteler: remove hardcoded version specific urls, use latest version

2018-12-04T10:28:30Z

remove hardcoded version specific urls, use latest version

← Older revision		Revision as of 10:28, 4 December 2018
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	== Introduction ==		== Introduction ==

	Overlapping areas (e.g. as stored in a SHAPE file) can be represented as a topological model through M:N mapping: each area can belong to several categories, several areas can have the same category. If you want to get the coverage for a particular Landsat scene, just select the path and row with where="PATH = x and row = y". See also the manual of {{cmd\|v.buffer~~\|version=70~~}} for a similar example.		Overlapping areas (e.g. as stored in a SHAPE file) can be represented as a topological model through M:N mapping: each area can belong to several categories, several areas can have the same category. If you want to get the coverage for a particular Landsat scene, just select the path and row with where="PATH = x and row = y". See also the manual of {{cmd\|v.buffer}} for a similar example.

	== FAQ ==		== FAQ ==

Neteler: +intro from M Metz grass-user

2015-01-15T09:05:32Z

+intro from M Metz grass-user

← Older revision		Revision as of 09:05, 15 January 2015
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			== Introduction ==

			Overlapping areas (e.g. as stored in a SHAPE file) can be represented as a topological model through M:N mapping: each area can belong to several categories, several areas can have the same category. If you want to get the coverage for a particular Landsat scene, just select the path and row with where="PATH = x and row = y". See also the manual of {{cmd\|v.buffer\|version=70}} for a similar example.

			== FAQ ==
	'''Q:''' How can I determine the number of overlapping features per location after import of SHAPE file?		'''Q:''' How can I determine the number of overlapping features per location after import of SHAPE file?

Neteler at 17:47, 31 July 2014

2014-07-31T17:47:51Z

← Older revision		Revision as of 17:47, 31 July 2014
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	v.to.rast input=fireHistory layer=1 output=mf use=attr column=countFires		v.to.rast input=fireHistory layer=1 output=mf use=attr column=countFires

	[[Category: FAQ]]		== See also ==

			* Intro to [[Vector Database Management\|vector data model]] (with drawing)
			* [[Vector topology cleaning]]
			* [[Vector topology]]
			* [http://grass.osgeo.org/programming7/vlibTopology.html#vlibTopoExamples Topology examples] (GRASS Programmer's Manual)

			[[Category:FAQ]]
			[[Category:Topology]]
	[[Category:Vector]]		[[Category:Vector]]

Neteler at 00:37, 7 December 2011

2011-12-07T00:37:06Z

← Older revision		Revision as of 00:37, 7 December 2011
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	[[Category: FAQ]]		[[Category: FAQ]]
			[[Category:Vector]]

⚠️Rkrug at 13:00, 8 July 2008

2008-07-08T13:00:01Z

← Older revision		Revision as of 13:00, 8 July 2008
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	'''A:''' You can run this (example) - note that it won't work with the DBF driver but requires SQLite, PostgreSQL, MySQL, or... driver:		'''A:''' You can run this (example) - note that it won't work with the DBF driver but requires SQLite, PostgreSQL, MySQL, or... driver:

			# solution one

	v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory		v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory

	v.category input=fireHistory output=tmpFire type=centroid		v.category input=fireHistory output=tmpFire type=centroid
	v.db.addtable map=tmpFire table=tmpFire_2 layer=2 columns='cat int'		v.db.addtable map=tmpFire table=tmpFire_2 layer=2 columns='cat int'
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	# another solution (tested under SQLite)		# another solution (tested under SQLite)
	v.overlay ainput=~~tmpFire~~ atype=area alayer=1 binput=~~tmpFire~~ btype=area blayer=2 output=mf operator=or olayer=1,1,1 --overwrite
			v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory

			v.overlay ainput=fireHistory atype=area alayer=1 binput=fireHistory btype=area blayer=2 output=mf operator=or olayer=1,1,1 --overwrite
	v.db.renamecol map=mf layer=1 column=b_cat,countFires		v.db.renamecol map=mf layer=1 column=b_cat,countFires
	v.db.update map=mf layer=1 column=countFires value=1 where='countFires isnull'		v.db.update map=mf layer=1 column=countFires value=1 where='countFires isnull'

			# Export it to a raster layer:
			v.to.rast input=fireHistory layer=1 output=mf use=attr column=countFires

	[[Category: FAQ]]		[[Category: FAQ]]

⚠️Rkrug at 08:50, 8 July 2008

2008-07-08T08:50:58Z

← Older revision		Revision as of 08:50, 8 July 2008
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	# another solution (tested under SQLite)		# another solution (tested under SQLite)
	v.overlay ainput=tmpFire atype=area alayer=1 binput=tmpFire btype=area blayer=2 output=mf operator=or olayer=1,1,1 --overwrite		v.overlay ainput=tmpFire atype=area alayer=1 binput=tmpFire btype=area blayer=2 output=mf operator=or olayer=1,1,1 --overwrite
	v.db.update map=mf layer=1 column=~~b_cat~~ value=1 where='~~b_cat~~ isnull'		v.db.renamecol map=mf layer=1 column=b_cat,countFires
			v.db.update map=mf layer=1 column=countFires value=1 where='countFires isnull'

	[[Category: FAQ]]		[[Category: FAQ]]

⚠️Rkrug at 16:07, 7 July 2008

2008-07-07T16:07:58Z

← Older revision		Revision as of 16:07, 7 July 2008
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	# Export it to a raster layer:		# Export it to a raster layer:
	v.to.rast input=tmpFire layer=2 output=mf use=attr column=num		v.to.rast input=tmpFire layer=2 output=mf use=attr column=num

			# another solution (tested under SQLite)
			v.overlay ainput=tmpFire atype=area alayer=1 binput=tmpFire btype=area blayer=2 output=mf operator=or olayer=1,1,1 --overwrite
			v.db.update map=mf layer=1 column=b_cat value=1 where='b_cat isnull'

	[[Category: FAQ]]		[[Category: FAQ]]

⚠️Rkrug at 14:48, 7 July 2008

2008-07-07T14:48:12Z

← Older revision		Revision as of 14:48, 7 July 2008
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	v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory		v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory
	v.category input=fireHistory output=tmpFire		v.category input=fireHistory output=tmpFire type=centroid
	v.db.addtable map=tmpFire table=tmpFire_2 layer=2 columns='~~num,~~int'		v.db.addtable map=tmpFire table=tmpFire_2 layer=2 columns='cat int'
	~~v.to.db map=tmpFire layer=2 qlayer=1 option=query col=num qcol='count(*)' type=centroid~~

	# Export it to a raster layer:		# Export it to a raster layer:

Neteler: won't work with the DBF driver

2008-06-24T12:47:10Z

won't work with the DBF driver

← Older revision		Revision as of 12:47, 24 June 2008
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	'''Q:''' How can I determine the number of overlapping features per location after import of SHAPE file?		'''Q:''' How can I determine the number of overlapping features per location after import of SHAPE file?

	'''A:''' You can run this (example):		'''A:''' You can run this (example) - note that it won't work with the DBF driver but requires SQLite, PostgreSQL, MySQL, or... driver:

	v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory		v.in.ogr dsn=./shp/ layer=fireHistory output=fireHistory

Neteler: +cat

2008-06-24T12:19:44Z

+cat

← Older revision		Revision as of 12:19, 24 June 2008
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	# Export it to a raster layer:		# Export it to a raster layer:
	v.to.rast input=tmpFire layer=2 output=mf use=attr column=num		v.to.rast input=tmpFire layer=2 output=mf use=attr column=num

			[[Category: FAQ]]