[GRASS-dev] v.build: why is attaching islands taking so long?

Hamish hamish_b at yahoo.com
Thu Dec 11 01:34:48 EST 2008


> Hamish pisze:
> "Florida coastline" problem

Maciej wrote:
> Skiming through GDAL 1.6 announce I noticed the following:
> 
> "Add a segmentize() method to OGRGeometry to modify the geometry such it
> has no segment longer then the given distance; add a -segmentize option
> to ogr2ogr"
> 
> Relevant?


perhaps, but distance would need to by by number of vertices, not map
distance - as maps can be of many scales and there is no single "max
distance". (I guess you could calculate map bounds and use 5% of max
side..) And you'd need a GDAL version check to stay backwards compatible
with older GDALs for the next 2-3 years or so. (extended Debian life cycle)

but I wonder, would a simple, but large, box of 4 vertices (corners) which
surrounds a complicated vector map (many islands) still take so long to
build? in that case, reducing the number of sequential vertices wouldn't
help.
???

probably need to run some trials with v.in.region + v.patch to test that.


Hamish



      



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