Now let's check for a more complex query in PostGIS to get our spatial juices flowing. We want to locate all the golf courses that are either inside or within 5 km of a national park or protected area. Plus, the golf course must be within 2 km of a city. The city data is derived from the tags in OSM where the tag place = city.
The national parks and protected areas for this query belong to the Government of Canada. Our golf courses and datasets of cities are derived from an OSM located in British Columbia and Alberta.
We need the data of all the national parks and protected areas in Canada, so go and make sure they're located in the /ch04/geodata/
folder.
The original data is located at http://ftp2.cits.rncan.gc.ca/pub/geott/frameworkdata/protected_areas/1M_PROTECTED_AREAS.shp.zip for download if you do not already have the /geodata
folder downloaded from GitHub.
The other datasets needed are the cities and golf courses...