plotting non regular (lon,lat) grids

[Dot Deb]

        As model output I have files with vars gridded on a regular
        Rotated Pole reference. In this frame the computational domain
        is represented by a rectangular coordinate system.

        I want to represent them in a Geographic lon/lat coordinate
        system back-rotating the computational domain to the geographic
        one. Each point of the computational grid is represented now
        by a couple of lon(i,j), lat(i,j) which gives a non-rectangular
        domain.

        Is there any way to represent it in GrADS with the underlying
        geograhic map?

        Alberto