GRASS 6.0
Heads up digitizing with v.digit
screenshot: O. Dassau
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Buffering with v.buffer
screenshot: R. Blazek
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Overlapping polygons input from Shapefile (or any other OGR simple feature format)
screenshot: R. Blazek
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Result (areas colored by number of overlapping areas, categories of layer 1 and 2)
screenshot: R. Blazek
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Example of import and use in GRASS
# GRASS 6.0:
v.in.ogr dsn=./shp/ layer=fire output=fire_p
v.category input=fire_p output=fire_c type=centroid field=2
echo "create table fire_c_2 (id int, num int)" | db.execute
v.db.connect map=fire_c driver=pg database=bridge layer=2 table=fire_c_2 key=id
v.to.db map=fire_c layer=2 option=cat col1=id
v.to.db map=fire_c layer=2 qlayer=1 option=query col1=num qcol="count(*)" type=centroid
Number of overlapping features is also written as category to centroid.
Another example of overlapping features in one layer (overpass)
screenshot: R. Blazek
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Vector overlay using v.overlay
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Input A and B
screenshot: R. Blazek
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intersection (operator=and)
screenshot: R. Blazek
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union (operator=or)
screenshot: R. Blazek
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not (operator=not)
screenshot: R. Blazek
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exclusive or (operator=xor)
screenshot: R. Blazek
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Charting using d.vect.chart
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Pie charts (default)
screenshot: R. Blazek
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Bar charts (ctype=bar)
screenshot: R. Blazek
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Shortest path using d.path
screenshot: R. Blazek
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Split network into bands using v.net.iso
screenshot: R. Blazek
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Allocate subnets using v.net.alloc
screenshot: R. Blazek
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