O'Reilly logo

PostGIS Cookbook by Bborie Park, Stephen Vincent Mather, Thomas J. Kraft, Paolo Corti

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Fixing invalid geometries

You will often find invalid geometries in your PostGIS database. These invalid geometries could compromise the functioning of PostGIS itself and any external tool using it, such as QGIS and MapServer. PostGIS, being compliant with the OGC Simple Features Specification, must manage and work with valid geometries.

Luckily, PostGIS 2.0 offers you the ST_MakeValid function that, together with the ST_IsValid, ST_IsValidReason, and ST_IsValidDetails functions, is the ideal toolkit for inspecting and fixing geometries within the database. In this recipe, you will learn how to fix a common case of invalid geometry.

Getting ready

Unzip the data/TM_WORLD_BORDERS-0.3.zip file into your working directory—working/chp3. Import the shapefile ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required