How can I detect saddle points in 2D vector data?

Hello, AM having troubles in finding the saddle point in a 2D vector data and please can give me hits.

thanks

[ab alm]

Thanks for your answer but it doesn't really shows how to detect saddle points in a 2d vector data

Answer 1

[KSSV]

http://stackoverflow.com/questions/30738979/find-saddle-points-in-matlab