Problem while generating the Triangle about noisemodelling HOT 2 CLOSED

This error is thrown by the JDelaunay library used to make a triangular mesh around buildings. The cause is a topology error in input buildings polygons.

In order to fix this issue you have to clean errors in the input model. You can use the following query to do this:

-- Clean buildings
-- Epsilon is the merge distance of two close points
set @EPSILON = 0.15;
drop table if exists BUILDINGS_CLEAN_MERG, BUILDINGS_CLEAN;
create table BUILDINGS_CLEAN_MERG AS SELECT ST_SIMPLIFY(ST_UNION(ST_BUFFER(ST_ACCUM(the_geom), @EPSILON / 2, 'join=bevel endcap=flat')),@EPSILON) the_geom from BUILDINGS;
-- Explode table
create table BUILDINGS_CLEAN AS SELECT * FROM ST_EXPLODE('BUILDINGS_CLEAN_MERG')
 where st_isvalid(the_geom);
-- Print total number of points
select ST_NUMPOINTS(the_geom) NUM_POINTS FROM BUILDINGS_CLEAN_MERG;
drop table if exists BUILDINGS_CLEAN_MERG;

This query try to merge and simplify buildings in order to remove small topological errors around polygons. You can change epsilon value in order to further approximate the buildings geometry (will cause some walls to be moved)

from noisemodelling.

Just for information :
A tool is under development in OrbisGIS to detect geometrical errors.

from noisemodelling.