[postgis-users] some wrong with geometry_overright()!

[Mark Cave-Ayland]

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net 
> [mailto:postgis-users-bounces at postgis.refractions.net] On 
> Behalf Of David Fan
> Sent: 08 March 2004 12:44
> To: postgis-users at postgis.refractions.net
> Subject: [postgis-users] some wrong with geometry_overright()!
> 
> 
> 
> 
> 
> PG_FUNCTION_INFO_V1(geometry_overright);
> Datum geometry_overright(PG_FUNCTION_ARGS)
> {
>  GEOMETRY     *geom1 = (GEOMETRY *)  
> PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
>  GEOMETRY     *geom2 = (GEOMETRY *)  
> PG_DETOAST_DATUM(PG_GETARG_DATUM(1));
>  
>  bool result;
> //printf("in geometry_overright\n");
>  
>  if (geom1->SRID != geom2->SRID)
>  {
>   elog(ERROR,"Operation on two GEOMETRIES with different SRIDs\n");
>   PG_RETURN_NULL();
>  }
>  
>   /*
>    *I think there is some wrong with the following
>    *It should be:
>    *result = FPge(geom1->bvol.LLB.x, geom2->bvol.URT.x);
>    */
>  result = FPge(geom1->bvol.LLB.x, geom2->bvol.LLB.x);
> 
> 
>  PG_RETURN_BOOL(result);
> }


Hi David,

The test in the code looks fine since it is checking to see whether the
geom1 overlaps or lies to the right of geom2. This is the test used for
the &> operator. It looks as if you need to check whether geom1 lies to
the right of geom2 which is the test used by the >> operator. Please
look at the >> operator and the geometry_right() function which should
have the behaviour you require.


Cheers,

Mark.

---

Mark Cave-Ayland
Webbased Ltd.
Tamar Science Park
Derriford
Plymouth
PL6 8BX
England

Tel: +44 (0)1752 764445
Fax: +44 (0)1752 764446


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