

   SSppaattiiaall TTooppooggrraapphhiicc DDaattaa

   AArrgguummeennttss::

        This data frame contains the following columns:

          x: x coordinates (units of 50 feet)

          y: y coordinates (units of 50 feet)

          z: heights (feet)

   DDeessccrriippttiioonn::

        The `topo' data frame has 52 rows and 3 columns, of
        topographic heights within a 310 feet square.

   SSOOUURRCCEE::

        Davis, J.C. (1973) Statistics and Data Analysis in
        Geology.  Wiley.

