GRASS GIS (Geographic Resources Analysis Support System)

GRASS 6 Screenshots

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User Interface (GUI)

Vector operations

Raster operations

3D and visualization

GRASS 6.1

GRASS 6 Screenshots - Vector Operations

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Heads up digitizing with v.digit

Buffering with v.buffer

Overlapping polygons

Overlapping polygons input from Shapefile (or any other OGR simple feature format)

Result (areas colored by number of overlapping areas, categories of layer 1 and 2)

Another example of overlapping features in one layer (overpass)

 

Example of import and use in GRASS

  • 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.

 

Vector overlay using v.overlay

 

Input A and B

 

intersection (operator=and)

union (operator=or)

 

not (operator=not)

exclusive or (operator=xor)

Charting using d.vect.chart

Pie chart

Pie charts (default)

Bar chart

Bar charts (ctype=bar)

Network analysis

v.net.iso

Split network into bands using v.net.iso

v.net.alloc

Allocate subnets using v.net.alloc

d.path

Shortest path using d.path


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