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 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
Enter a name for the existing grid1 file. The default directory is
the Carlson data directory.
Extrapolate grid to full grid size
[Yes/<No>]? press Enter
Select Source Grid 2 File Dialog
Enter a name for the existing grid2 file.
Select the Inclusion perimeter
polylines or ENTER for none. press Enter
Select the Exclusion perimeter
polylines or ENTER for none. press Enter
Merged Grid File to Write Dialog
Enter a name for the new grid file.
Pulldown Menu Location: Surface
Keyboard Command: mergegrd
Prerequisite: Two grid (.GRD) files
File Name: \lsp\makegrid.arx