[postgis-users] totopogeom resulting in SQL/MM Spatial exception

Bo Guo bo.guo at gisticinc.com
Wed Jan 16 10:00:37 PST 2019

OK, I can understand the concept why this is the case now. But if there 
is any example or reference article on line that would be of great help.


On 1/16/19 10:37 AM, Sandro Santilli wrote:
> On Wed, Jan 16, 2019 at 10:26:12AM -0700, Bo Guo wrote:
>> strk,
>> Here is how it break up the topo geom conversion (l_tolerance is 0.0000001)
>>              LOOP
>>                  WITH foo AS (SELECT grd_id FROM azgiv.roadcenterlines
>>                                  WHERE grd_topo_geom IS NULL
>>                                      LIMIT l_batch_size)
>>                  UPDATE azgiv.roadcenterlines
>>                                  SET grd_topo_geom =
>> topology.totopogeom(grd_geom, 'azgiv_topo', l_topo_layer_id, l_tolerance)
>>                                  FROM foo
>>                                  WHERE foo.grd_id = roadcenterlines.grd_id;
>>                  GET DIAGNOSTICS l_rowcount = ROW_COUNT;
>>                  EXIT WHEN l_rowcount < l_batch_size;
>>              END LOOP;
> The goal of chunking was to get partial results rather than an
> all-or-nothing behavior. If you use that plpgsql loop you'll want
> to catch exceptions and set those TopoGeometries to NULL instead.
> Then you'll be able to see what the loop was able to convert and
> what not, and get back to the still-to-be-converted geoms, maybe
> after cleaning up some of what you got converted already.
> --strk;
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