Import Error in Postgis: AddGeometryColumn does not exist

Untangling the PostGIS “AddGeometryColumn Does Not Exist” Headache

So, you’re diving into the world of spatial databases with PostGIS, and BAM! You get hit with the dreaded “function addgeometrycolumn… does not exist” error. Trust me, we’ve all been there. It’s like hitting a brick wall when you’re just trying to get your map data up and running. This error basically means PostGIS can’t find a crucial function, AddGeometryColumn, which is kind of a big deal. It’s the function that lets you add a geometry column (where you store your map data) to your database tables. Without it, you’re stuck.

Think of AddGeometryColumn as the key ingredient in a spatial recipe. It tells your database how to store those points, lines, and polygons that make up your maps. It defines what kind of spatial data you’re dealing with – is it a point, a line, or a polygon? It also sets the spatial reference system (SRID), which is like telling your GPS where on Earth your data is located.

But why does this error happen? Let’s break it down.

The Usual Suspects

There are a few common reasons why you might run into this problem. More often than not, it boils down to one of these:

Time to Fix It!

Alright, enough with the problem – let’s talk solutions. Here’s how to get rid of that “AddGeometryColumn does not exist” error for good: