No elevations are calculated on grid cells that extend beyond
the extent of the data. Extrapolation can be used to calculate
elevations for the grid cells that are beyond the data limits. The
prompt Extrapolate grid to full grid size? shows when there
are grid cells with no elevation in a grid (.GRD) file.
Extrapolation fills in all the grid cells. The method to
extrapolate uses a safe calculation that tends to average out or
level the extrapolated values. So extrapolated grid areas are not
as accurate as grid areas within the limits of the data.
Select Source Grid 1 File Dialog (file select dialog)
Reading cell> 93058
Extrapolate grid to full grid size [Yes/<No>]?
press Enter
Select Source Grid 2 File Dialog (file select dialog)
Reading cell> 62137
Extrapolate grid to full grid size [Yes/<No>]?
press Enter
Overlap method: Hold grid 1, replace with grid 2 or average
[Hold/Replace/<Average>]?press Enter
Specify inclusion and exclusion areas for grid 2. Grid 1 used
everywhere else.
Select the Inclusion perimeter polylines or ENTER for none.
select perimeter(s)
or press Enter
Select objects: press
Enter to conclude selection
Select the Exclusion perimeter polylines or ENTER for none.
select perimeter(s)
or press Enter
Select objects: press
Enter to conclude selection
Merged Grid File to Write Dialog(new file select dialog)
Pulldown Menu Location: Surface >> Modify Grid File
Keyboard Command: mergegrd
Prerequisite: Two grid (.GRD) files