Splitting a large terrain mesh in m x n grid quickly. Is this possible?

Hi,

I have a large terrain of 1 million polygons. Is there a quick way / script to split this terrain into chunks of m x n smaller polygons?
I can do it manually by using Edit mode and manually split it by using [P] key.

Regards,
Iwan

Split [P], meaning cutting parts of it out into separate object, right? It’s easy. In Edit mode, display the map in top orthographic view, Num pad [7]. Set if to vertex mode. Hit [A] key few times to deselect everything. Then box select [B] the part you want. Then hit [P].