Dissolve polygons: Difference between revisions

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'''Q:''' How to dissolve vector polygons (or remove tile boundaries of adjacent maps)
'''Q:''' How to dissolve vector polygons (or remove tile boundaries of adjacent maps)


'''A:''' Dissolving of areas is done with v.dissolve (v.extract -d). If tile boundaries of adjacent maps (e.g. CORINE Landcover SHAPE files) have to be removed, an extra step is required to remove duplicated boundaries:
'''A:''' Dissolving of areas is done with {{cmd|v.dissolve}} (v.extract -d). If tile boundaries of adjacent maps (e.g. CORINE Landcover SHAPE files) have to be removed, an extra step is required to first remove duplicated boundaries:


Remove duplicated tile boundaries:
Remove duplicated tile boundaries:
     v.clean clc2000_patched out=clc2000_clean tool=snap,break,rmdupl thresh=.01
     v.clean clc2000_patched out=clc2000_clean tool=snap,break,rmdupl thresh=.01
 
Reclass based on desired column:
    v.reclass clc2000_clean out=clc2000_recl col=CODE_00


Dissolve:
Dissolve:
     v.dissolve input=clc2000_recl output=clc2000_final
     v.dissolve input=clc2000_clean output=clc2000_final


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

Latest revision as of 21:57, 10 April 2013

Q: How to dissolve vector polygons (or remove tile boundaries of adjacent maps)

A: Dissolving of areas is done with v.dissolve (v.extract -d). If tile boundaries of adjacent maps (e.g. CORINE Landcover SHAPE files) have to be removed, an extra step is required to first remove duplicated boundaries:

Remove duplicated tile boundaries:

    v.clean clc2000_patched out=clc2000_clean tool=snap,break,rmdupl thresh=.01

Dissolve:

    v.dissolve input=clc2000_clean output=clc2000_final