[postgis-users] gpc lost database connection - how to debug?

[Nicolas Ribot]

Hello Robert,

Glad to see you succeeded in using this code.
As soon as I have some time, I will try to complete it by dealing with
Multipolygons containing only one geometry (to be able to use polygon tables
created by shp2pgsql).

Be careful of an existing "bug" (well, a known bug I mean :-) ): If a
polygon has one of its interior rings touching the polygon's boundary at one
point, the result of the intersection between this polygon and another one
can be wrong, as GPC interiors cannot touch exterior polygons.

I was inaccurate in my description of the makefile I modified to compile
this code: the gpc C code must be compiled too. Sorry for that.

Nicolas.

"Robert W. Burgholzer" wrote:

> Many thanks to Paul and Nicolas, postgis with the gpc geoprocessing
> routines piggybacked onto it is now running.
> My problem stemmed from the fact that the Makefile for postgis needed to
> have a reference for "gpc.o" in it, in order for it to be declared in
> libpostgis.so.0.7. Running postmaster from the command line, not
> backgrounded, yielded the appropriate error message which allowed me to
> figure this out. I am fairly un-familiar with Makefile's etc., so this
> was a mistake I made.
> In my breif testing thus far, I have performed an intersection with 2
> shapes, one containing 4 points, the other with over 80, and the
> resultant was in the 80 point range.
>
> I don;t know if anyone else will find this useful, but it was compiled
> on a redhat 7.0 box, postgis 0.7, and postgres 7.2, 233 Mhz machine with
> 64 Megs of ram. The aforementioned intersection completed in the order
> of magnitude of 10ths of a second.
>