IsLess2D is a comparator that compares based on the size of the x and y coords.

NewFlatCoordSorting creates a sort.Interface implementation based on the Comparator function.

NewFlatCoordSorting2D creates a Compare2D based sort.Interface implementation.

FlatCoord is a sort.Interface implementation that will result in sorting the wrapped coords based on the comparator function Note: this data struct cannot be used with its 0 values.

IsLess the function used by FlatCoord to sort the coordinate array returns true is v1 is less than v2.