15.78.18  Mesh_examples 

Assume you have mesh data X,Y (ROW,COLUMN) of size 20, 30.
     TD:X=X MINUS 5
Shifts the X scale
     TD:Y=Y TIMES 2
Expands the Y scale
     TD:Z=10 ROW=5 COLUMN=3
Modifies 1 entry
     TD:Z=0
Sets all mesh values to 0.0 
     TD:Z=Z PLUS 1 ROW=5 TO 10 COLUMN=3 TO 5
Adds 1 to all mesh values for the specified range of rows and columns.  15
values are modified.