Given a database of GPS points, a center GPS location, and a radius R (in meters), how can I find all points in the database that are within a distance of R of the center point?
Will the distance iso-lines be an ellipse?
GPS Distance – How to Measure Distance Between GPS Coordinates
distancegps
Best Answer
For such short distances and since you are doing the coding yourself, the flat earth equations would probably be a good enough approximation but it depends on your accuracy requirements.
Compute the distance from latp,lonp to lat1/lon1 via the equirectangular projection:
Latp/Lonp will be your reference lat/lon (in radians!). Lat1/Lon1 will be the point you are testing. Once you have distance, it is an easy test to determine if the point lies within your circle.
Reference: section Equirectangular approximation at the site: http://www.movable-type.co.uk/scripts/latlong.html