we’re all familiar with the whole “thai food near me” thing. you type that phrase into your phone and it responds with a list of thai restaurants that are, well, _near you_. and we have a kind-of understanding of how that works under the hood: google or whoever has a database of thai restaurants with their latitudes and longitudes and knows our location from our phone and then does ‘some process’ to figure out which thai places are nearby.
in this post,we’ll be going over that ‘some process’ part, looking at how to use mysql to do some standard location stuff. we’ll cover mysql’s `POINT` and `POLYGON` types, finding the distance between two points on a sphere (which the earth, contrary to what you may have read on the internet, is), determining if a point is inside of a polygon defined by points, and look at things like ‘spatial reference systems’ which define how coordinates are plotted on the surface of the earth.
