4.2 Doing Interpolation and Approximation with your own data sets

It is helpful to use awk (or perl) scripts to bring data sets into the form needed by the program.

I used for example the following script for extracting the columns for x, y, and z from a data file, putting commas between them, and braces around each point. I also used this script to subtract a certain offset from the x and y coordinates (which were in the Gauss Krueger coordinate system).

BEGIN { print "(" }
      { print "(", $2-2000000.0, ",", $3-5000000.0, ",", $4, ")," }
END { print ")" }

Then I made an input file with an editor in which i used the output from the script as the point list.