[GRASSLIST:6449] How to remove nested vector islands?

[Patton, Eric]

I have a series of vested vector polygons, progressing from largest to
smallest, they are:

 

1) Polygon of marshland;   2) Polygon of small lake within larger marshland
polygon;   3) Polygon of very small islands within lake

 

All three polygon boundaries are currently attributed as 'marshland', so I
need a way of assigning new attributes to the vector boundary and area for a
large number of polygons in my mapset. Do the boundary portion and area
potion of a Grass 6.0 vector require separate attribution? And once the lake
polygons and island polygons have had their attributes changed from
marshland, how can I clip out the lake polygon from the larger marshland
while maintaining the island polygons?

 

Sorry if my questions seem muddled, I'm relatively new to using the 6.0
vector programs. I may not be asking the right kind of questions I need to.

 

Thanks,

 

  

~ Eric. 

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

Eric Patton

 

Technologist, Geo-Spatial Data Services

Geological Survey of Canada (Atlantic)

Natural Resources Canada

Bedford Institute of Oceanography

Dartmouth, Nova Scotia, Canada B2Y 4A2

 

Postal address: P.O. Box 1006

Courier address: 1 Challenger Drive

 

Telephone: (902)426-7732

Facsimile:  (902)426-4104

E-mail:        <mailto:epatton at NRCan.gc.ca> epatton at NRCan.gc.ca

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/grass-user/attachments/20050413/602ca9d8/attachment.html