[GRASS-user] vector area needs water fill

Nikos Alexandris nikos.alexandris at felis.uni-freiburg.de
Mon Feb 16 20:37:11 EST 2009


On Mon, 2009-02-16 at 20:01 -0500, Kurt Springs wrote:
> Hi folks,
> I do have another problem I would like some thoughts on.
> 
> I have vector areas representing water areas (lakes and oceans).  I  
> purchased these areas from the Irish and Northern Irish Ordinance  
> Survey.  They came as .dxf packages.  I extracted them but they would  
> not fill.  I opened them in v.digit and found that the vector lines  
> were broken, even missing in places.  I did my best to close the  
> vectors.  The ocean was just a coastline.  I had to modify it by  
> attaching a the bounding box and taking away everything that didn't  
> look like the ocean.  Getting these areas to fill even though I think  
> I managed to join most of the nodes.  Some I think I really did join,  
> some I know would not join.

> Is there a simple(ish) way to generate areas that will be I can turn  
> blue and say "here are the lakes and oceans"?  I don't need them for  
> analysis, but I would like to put maps generated into my dissertation  
> and have them be pleasing to the eye.
> 
> Any help on this will be appreciated.
> Kurt

FWIW,

once I received a .dxf file that contained burned areas digitised by
GPS-supported devices. After getting the file in GRASS, it looked really
bad. As you describe, open "boundaries", missing parts of lines.

I had to "restore" it manually. I don't think there is another option
than hard-hand-working here. Except if you are lucky and you could use
v.clean to close boundaries, add centroids with v.centroid and play
around with colors. But I doubt it.

Kind regards, Nikos



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