[Gdal-dev] OGR and support for older PostGIS DBs?

[Frank Warmerdam]

On 8/1/05, Markus Neteler <neteler at itc.it> wrote:
> Hi,
> 
> I was trying the current OGR (today) against an older
> PostGIS database (based on libpostgis.so.0.7 and PostgreSQL V7.3.3):
....
> I am not sure what's wrong... AFAIK I didn't touch the PG DB for a long
> while. Is backward compatibility supported? Otherwise I'll have to upgrade
> my PG database.
> 
> This patch cured at least the BOX3D problem:
> --- ogr/ogrsf_frmts/pg/ogrpgtablelayer.cpp      20 Jul 2005 01:45:30 -0000      1.29
> +++ ogr/ogrsf_frmts/pg/ogrpgtablelayer.cpp      1 Aug 2005 17:18:19 -0000
> @@ -1282,7 +1282,7 @@
>                 szVals[strstr(ptr,")") - ptr] = '\0';
> 
>                 char ** papszTokens = CSLTokenizeString2(szVals," ,",CSLT_HONOURSTRINGS);
> -               if ( CSLCount(papszTokens) != 4 )
> +               if ( CSLCount(papszTokens) != 6 )
>                 {
>                         CPLError(CE_Failure, CPLE_IllegalArg, "Bad extent representation: '%s'", pszBox);
>                         CSLDestroy(papszTokens);
> 
> 
> Help is appreciated,

Markus,

Sorry about this.  I asked Andrey and Oleg to look into this yesterday,
but I believe Andrey is travelling today.  I am commiting the following
patch which I think should support the BOX3D if it is returned by 
the Extent() operator.   I am not sure if this is a postgis version issue or
not, but it is my intention to continue supporting earlier versions of
PostGIS for a year or two at least. 

diff -u -b -r1.29 ogrpgtablelayer.cpp
--- ogrpgtablelayer.cpp 20 Jul 2005 01:45:30 -0000      1.29
+++ ogrpgtablelayer.cpp 3 Aug 2005 13:18:49 -0000
@@ -1282,9 +1282,11 @@
                szVals[strstr(ptr,")") - ptr] = '\0';
 
                char ** papszTokens = CSLTokenizeString2(szVals," ,",CSLT_HONOUR
STRINGS);
-               if ( CSLCount(papszTokens) != 4 )
+        if ( CSLCount(papszTokens) != 4 
+             && CSLCount(papszTokens) != 6 )
                {
-                       CPLError(CE_Failure, CPLE_IllegalArg, "Bad extent repres
entation: '%s'", pszBox);
+            CPLError(CE_Failure, CPLE_IllegalArg, 
+                     "Bad extent representation: '%s'", pszBox);
                        CSLDestroy(papszTokens);
                        PQclear(hResult);
                        return OGRERR_FAILURE;
@@ -1292,8 +1294,21 @@
 
                psExtent->MinX = CPLScanDouble(papszTokens[0],strlen(papszTokens
[0]),"C");
                psExtent->MinY = CPLScanDouble(papszTokens[1],strlen(papszTokens
[1]),"C");
-               psExtent->MaxX = CPLScanDouble(papszTokens[2],strlen(papszTokens
[2]),"C");
-               psExtent->MaxY = CPLScanDouble(papszTokens[3],strlen(papszTokens
[3]),"C");
+
+        if( CSLCount( papszTokens ) == 4 ) // BOX2D
+        {
+            psExtent->MaxX = CPLScanDouble(papszTokens[2],
+                                           strlen(papszTokens[2]),"C");
+            psExtent->MaxY = CPLScanDouble(papszTokens[3],
+                                           strlen(papszTokens[3]),"C");
+        }
+        else // BOX3D
+        {
+            psExtent->MaxX = CPLScanDouble(papszTokens[3],
+                                           strlen(papszTokens[4]),"C");
+            psExtent->MaxY = CPLScanDouble(papszTokens[4],
+                                           strlen(papszTokens[5]),"C");
+        }
 
                CSLDestroy(papszTokens);

Note my change differs from yours in that it correctly extract
the extents in the case of a BOX3D and in that it continues
to support the 2D version of the box. 

Andrey / Oleg, perhaps you guys could verify the changed 
code makes sense in all circumstances. 

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent