Count points in raster cells - Revision history

Neteler at 18:06, 31 December 2013

2013-12-31T18:06:06Z

← Older revision		Revision as of 18:06, 31 December 2013
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	[[Category:FAQ]]		[[Category:FAQ]]
			[[Category: Vector]]

⚠️MarisN: Add area counting example

2010-07-06T12:26:08Z

Add area counting example

← Older revision		Revision as of 12:26, 6 July 2010
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	v.out.ascii input=myvec format=point \| r.in.xyz input=- output=myras method=n type=FCELL x=1 y=2 z=3		v.out.ascii input=myvec format=point \| r.in.xyz input=- output=myras method=n type=FCELL x=1 y=2 z=3

			'''Q:''' But what if I need to count vector areas and not points per raster cell?

			'''A:''' Create vector grid with desired cell size; Overlay it with area layer You want to count; Adjust GRASS region to match vector grid and then use same method as described for points. Example found at [http://www.gisnet.lv/gisnet/2010/07/objektu-skaits-platibas-vieniba-skaitam-laukumus GISnet.lv]

			Example:
			v.mkgrid map=soil_grid grid=7,9 position=coor coor=595000,4920000 box=1000,1000
			v.overlay ainput=soil_grid atype=area binput=soils@PERMANENT btype=area output=soil_on_grid operator=and
			g.region vect=soil_grid res=1000
			v.out.ascii input=soil_on_grid format=point fs='\|' dp=2 layer=1 where="b_label='VaB'" \| \
			r.in.xyz input=- output=VaB_count method=n

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

Neteler: new from ML

2010-04-09T19:03:04Z

new from ML

New page

'''Q:''' How can I count the number of points which fall into a raster cell? I want to count vector points by region resolution (quadrat count) and write the results to a raster map (in order to perform r.mapcalc on these observed frequencies).

'''A:''' Use {{cmd|r.in.xyz}} with 'method=n' which will count points per cell (resolution chosen with {{cmd|g.region}}) and write a raster map allocating the number count to the cell.

Example:

v.out.ascii input=myvec format=point | r.in.xyz input=- output=myras method=n type=FCELL x=1 y=2 z=3

[[Category:FAQ]]