Converting ASCII data to raster format

Hello all,

Can anyone help me?

Situation:

  1. Have 2 ASCII data files. x, y, and z coordinates.
  2. One file contains nearshore data and the other
      contains offshore data.
  
Goal:

  1. Combine data to make a raster map of combined data.

Have tried:

  1. s.in.ascii and s.surf.tps under no tension
      When nearshore and offshore is done seperately,
      the contours come out looking good.

  2. Tried combining and the offshore plays havic on
      the onshore.

Data Profile should look like

15 ft x
         x
          x
  -15 ft x
              x
                 x
                   xxxxxxx
                          xxxxxxxxxxxxxxxxxxxxxxxxxx
It has a quick drop on one end in a short duration and
a lone and steady decline.

Can anyone tell me if I can combine the two maps and do some
manipulation around the edges or can I put the data together
and come up with a better approximation. Would tension help?
What would a good tension to try?

This process is time consuming. An hour and half per try.
Any help would be appreciated.

Kym M. Lenkus
Davidson Laboratory
Hoboken, NJ 07030