PostGIS ERROR: BOOM! Could not generate outside point!

Question

This may be a continuation of a closed thread.

I want to sum the areas of polygons over categories in a large data set (avian species ranges), like this:

select sciname,
       sum(ST_Area(the_geom::geography)) / 1000000 as km2
from gis.aviandists_pl
group by sciname
order by sciname;

Some rows trigger 'ERROR: BOOM! Could not generate outside point!'. I've isolated a row that is causing this problem, but haven't found a way to upload it here. Based on the thread linked to above, I thought it might be a globe-spanning polygon, but it doesn't appear that way (see image below). This represents a single row from a geometry table, which surprises me because I would have thought that the multiple polygons that I'm observing would have to be represented by multiple records. Could this actually be a global polygon with small holes? More importantly, how can I work around this? The query covers over 10k rows, and I have no idea how many may pose this problem or how to find them. I'd be happy to share a shapefile of the problem data if that would help, but I haven't found a way to attach one here.

Answer 1

Yah that's Paul Ramsey's error message. I laugh every time I see that error posted :)

If you can output the ST_AsText of one of the offending rows here, that would be helpful.

Alternatively you can post to the PostGIS newsgroup.

http://postgis.refractions.net/mailman/listinfo/postgis-users where you can attach at least a small SQL file.

There were also a couple of BOOM errors fixed I think in the last release.

Do a SELECT postgis_full_version();

and make sure you are running PostGIS 1.5.4 or PostGIS 2.0.0+