Rough computation of distance between 2 points

Question

I want to calculate the rough (approximate) distance between two points to reduce the computation overhead.

I am using the following formula for the distance between (x1, y1) & (x2, y2):

Dist = Mod (x1 - x2) + Mod (y1 - y2)

Where Mod is the Modulus operator such that Mod(x) = |X|.

This seems to be working.

I want to know, if I have missed out something ...

Answer 1

Graphical representation of three usual distances:

(Note: this represents a circle of radius 4 in these three metrics.)

Answer 2

As long as you're getting the absolute value (like you stated |X|) and not using the modulus function then that will give you the manhattan distance between the two points

If that is what you want, then you've not missed anything

If you want the straight line distance use the pythagorean theorem. This is sqrt((x1 - x2) ^ 2 + (y1 - y2) ^ 2)