Coutouring random point data

From: Don Eliason (eliason AT unknown)
Date: Mon Mar 18 1996 - 12:12:17 MST


Nancy Westcott wrote:

> I would like to contour random point data (latitude and longitude coordinates).
>
> Currently, I transform the data into a regular 2-D gridded array
> using a fortran program and then use CPRECT to contour the data.
>
> Is there a routine to contour non-gridded data?
>

The short answer is no, not in NCAR Graphics.

You could, of course, use bivar, as supplied with NCAR Graphics,
to do your gridding, but it sounds like you already have a gridding
program. I hear that a future release will include alternative(s)
to bivar, such as possibly Dave Watson's nearest neighbor gridding.

An alternative, since your data is in latitude and longitude
coordinates, would be to use spheremap (ftp://climate.geog.udel.edu),
which was specifically designed to properly take into account spherical
geometry. Again, this only does the gridding; you still get to use
CPRECT to do the contouring.

Good luck,
Don Eliason
eliason AT unknown



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