Finding a coordinate in a circle

Question

I am doing a mashup using Google Maps under Grails where users can create geofences by selecting a point on the map and a radius. This get stored on my database and the appl

Answer 1

Well, if it doesn't need to be "perfect", you don't need to worry about plotting circles or anything like that. You can just take the two locations (the location you want to test, and the center of the circle) and use Pythagorus to find the distance. If that distance is less than the radius of the circle, it's inside.

There is a caveat to take into consideration, however: the reason this wouldn't be perfect is that that for your points, you're probably going to get a latitude and longitude...and the Earth is a sphere. So near the poles of the Earth this will kind of fall apart. But it may well be good enough for what you're doing.