Spatial concepts
Understanding how spatial statements are constructed and how to customize them for your queries is an important task in learning new ways to interact with spatial datasets.
ST_Within
The synopsis of ST_Within
includes the following:
boolean ST_Within(geometry A, geometry B);
A true and false determination is provided to determine if geometry A
is entirely within geometry B
.
You will need to be comfortable with SELECT
statements. Consider the following code. I am interested in buildings located within protected areas. I need to SELECT
the buildings and would like to identify them by their name and fid
. Geopackages often use fid
as their unique identifier, although it isn’t often necessary since OSM has its own identification for its features. I grabbed it here as an example. Any unique identifier will work. I ran the following query in pgAdmin
.
The name, fid
, and geometry (point) are displayed in the output window once you run the code. ST_AsText...