Removing duplicate columns and rows from a NumPy 2D array

I’m using a 2D shape array to store pairs of longitudes+latitudes. At one point, I have to merge two of these 2D arrays, and then remove any duplicated entry. I’ve been searching for a function similar to numpy.unique, but I’ve had no luck. Any implementation I’ve been
thinking on looks very “unoptimizied”. For example, I’m trying with converting the array to a list of tuples, removing duplicates with set, and then converting to an array again: