Calculating distance between two points using pythagorean theorem [closed]

Answer 1

You can use a simple pythagoras triangle if you expect the distances involved to be small compared with the size of the Earth.

Suppose you are at (lat0, long0) and you want to know the distance to a point (lat1, long1) in "latitude units".

Horizontal (EW) distance is roughly

d_ew = (long1 - long0) * cos(lat0)

This is multiplied by cos(lat0) to account for longitude lines getting closer together at high latitude.

Vertical (NS) distance is easier

d_ns = (lat1 - lat0)

So the distance between the two points is

d = sqrt(d_ew * d_ew + d_ns * d_ns)

You can refine this method for more exacting tasks, but this should be good enough for comparing distances.

In fact, for comparing distances, it will be fine to compare d squared, which means you can omit the sqrt operation.