How to determine if postgis is enabled on a database?

Question

I wanted to know if there is a way to determine that PostGis was enabled on a database.

I am trying to replicate my production server with my dev machine and I am not sure if the database on my dev machine had either PostGIS or postgis_topology enabled or both.

I tried looking around for a solution but could not come up with anything.
Any suggestions in this regard would be helpful.

Answer 1

Assuming that you have access to your database (either through the terminal or the pgadmin application), try the following:

1. Connect to your database

2. Run one (or both in order if you like) of the following queries:

   SELECT PostGIS_version();
   SELECT PostGIS_full_version();
   

if no error occurs, then you have PostGIS enabled for that database.

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References:

• https://postgis.net/docs/PostGIS_Version.html
• https://postgis.net/docs/PostGIS_Full_Version.html
• https://ase-research.org/training/PostGIS_2016/install.shtml#post4

Answer 2

I'd just like to add to John Moutafis' response since at this point I can't comment on an answer.

My situation was a bit different because I had created the postgis extension for a different schema, let's call it schema_name:

CREATE EXTENSION postgis SCHEMA schema_name

Just running the accepted answer's query gave me an error stating that "No function matches the given name and argument types". Instead I had to make sure to add the schema name prior to the function call, as depicted below:

SELECT schema_name.PostGIS_version();
SELECT schema_name.PostGIS_full_version();

That ended up working for me.