This command recalculates the surface model in a .grd file by using additional point data along with the original point data. Only .grd files created by the Make Drillhole Grid File command, in StrataCalc, can be used by Update Grid File. Make Drillhole Grid file stores a point file of the original data used to calculate the grid in a file with the same name as the grid file plus the extension .pnt. For example Make Drillhole Grid File will create stratax.grd and stratax.pnt.
The new point data for recalculation can be specified by picking points, entering point numbers that reference stored points in the current coordinate file, or selecting coal sections (from Place Coal Sections). When updating from coal sections, the program will prompt for a grid file that models the top of the coal sections. Since coal sections have thickness values but no Z values, this top of section grid is used to set the coal sections in the real Z axis. The program then updates the grid files that model each of the bottom elevation surfaces of the strata in the coal sections.
The updated grid can be saved in a new .grd file name or overwrite the original grid file by specifying the same file name. The location and resolution of the grid cannot be updated. So the original location and resolution should be made large enough to include any new area of point data to be added by Update Grid File.
Update grid from points or coal sections
(Points<Sections>)? Points
Grid File to Update file selection dialog
Choose the .grd file to update.
Pick point or point number: 35
Pick point or point number: press Enter
Choose modeling method (<Triangulation>/Inverse
distance/Kriging)? press Enter
Specify Grid File to Make
The updated grid will be stored in this .grd file.
Pulldown Menu Location: Surface
Keyboard Command: grdupdate
Prerequisite: Grid file created by Make Drillhole Grid
File