[GRASSLIST:5983] Re: speeding up v.in.ogr

[Chris Fonnesbeck]

On Thu, 3 Mar 2005 15:33:06 +1300, Hamish <hamish_nospam at yahoo.com> wrote:
> Chris:
> >>> I have been trying to import a detailed shapefile of the florida
> >>> coast (about 24M) into grass6.0b2, using v.in.ogr. Unfortunately,
> >>> having started 3 days ago, the import has not yet completed. It is
> >>> making progress, as the number of intersections is incrementing,
> >>> however this surely should not be taking quite this long. Are there
> >>> ways of speeding up the process?
> >>>
> >>> I am on a 1GHz OS X Powerbook with 1GB RAM.
> 
> Radim:
> >>Is it one or few big shapes or many small?
> 
> Chris:
> > It is the florida coastline, so it should be one large shape, with
> > plenty of small islands scattered alongside.
> 
> Radim:
> >> Then the problem is that bounding box of that long boundary
> >> intersects all the islands and v.in.ogr will try to break those
> >> lines which takes long time. It was already discussed here. Try to
> >> modify v.in.ogr so that it writes long boundaries in more shorter
> >> parts.
> 
> It was discussed off list, correspondence (including patch) follows.
> 
> I only come up against this myself every couple of months so have just
> it be slow, but I've got a detailed coastline vector map with the
> occasional offshore island .. it is topologically clean, but same long
> time to process issues.
> 
> Hamish
> 

It seems that Lorenzo was at least partly correct; there seems to be
an OSX issue. Importing the file in Linux completed in just a couple
hours.

C.