I'm new to PostGIS and I'm just trying to get a good grasp of the basics.
I've taken a dataset containing information on the world's cities, from https://www.maxmind.com/en/free-world-cities-database and imported it into a table.
I added a geometry column with:
SELECT AddGeometryColumn('cities', 'geom', 4326, 'POINT', 2);
And then populated the column with:
UPDATE cities SET geom = ST_SetSRID(ST_MakePoint(longitude, latitude), 4326);
I want to find all cities within the radius of a specific lat/lon. To do that I tried:
SELECT * FROM cities WHERE ST_DWithin(geom, ST_MakePoint(79.3832,43.6532)::geography, 50000);
...but no results are returned. The lat/lon I entered is that of the city of Toronto and I've verified that a record for Toronto exists in the table with the correct lat/lon.
If I increase the radius to something ridiculous, such as "5000000" a list of cities - most of which appear to be places on other continents - is returned. What am I doing wrong? Is it my query? Am I filling the geom column incorrectly?