ST_Relate() and ST_RelateMatch(): using DE-9IM in the most painless way

[Alessandro Furieri]

Hi List,

the next version of SpatiaLite will effectively support both

ST_Relate() and ST_RelateMatch() in the same form already

supported by PostGIS.

This is a really interesting option for at least two reasons:

1. determining "odd/extravagant" spatial relationships not 

   directly supported by standard SQL functions.

2. faster computing of multiplel spatial relationships 

   between the same pair of Geometries.

   

Directly using ST_Relate() and ST_RelateMatch() strictly

requires at least a basic knowledge about the DE-9IM model,

and unhappily DE-9IM is neither easy nor intuitive.

https://www.gaia-gis.it/fossil/libspatialite/wiki?name=about+DE-9IM

This new wiki-page is specifically intended to make easier 

(less painful) for average users taking full profit from 

the awkward DE-9IM.

enjoy,

Sandro