The ascii data file has a simple format qith each row reopresning a 
node with the following implied information (in metric units) Column 1: x-coordinate Column 2: y-coordinate Column 3: height Column 4: boundray flag (1 for boundary, 0 otherwise). eg.
0.0000000e+00 0.0000000e+00 -4.9294669e+02 1.0000000e+00
3.6000000e+05 0.0000000e+00 -4.9512170e+02 1.0000000e+00
1.0000000e+06 0.0000000e+00 -4.5962134e+02 0.0000000e+00
0.0000000e+00 1.0000000e+06 -4.7911359e+02 0.0000000e+00
1.0000000e+06 1.0000000e+06 1.5074872e+03 0.0000000e+00
0.0000000e+00 5.2428800e+05 -4.8391574e+02 1.0000000e+00 .... .... ....