What is the difference between knnsearch and rangesearch?

I need to find the number of data points within a circle of a 10 km radius. The data would be the latitude and longitude coordinates of my location point. Which function would be the best approach?

Answer 1

[KSSV]

difference is:

knnsearch: For a given positive integer K, knnsearch finds K points in X that are nearest each Y point.

rangesearch: for a given positive real value r, rangesearch finds all the X points that are within a distance r of each Y point.

So in your case if you want all the points (lat,lon) which are in a radius 10 kms, you have to use rangesearch