This is the easiest yet still equally accurate method for
calculating volumes. For this command, volumes are calculated in
one step by a simple window of the area, selecting the items, and
calculate.
First, you must specify the grid location and resolution. The
grid location should enclose the area for volume calculations. Next
the program asks for the layer names of the entities for the base
and final surfaces. You designate the layers to use for each
surface either by typing the layer names or by picking from the
screen, then during the routine you select the entities to use. You
may safely use the keyword ALL to select the entities, since you
have pre-defined the layers to use, and all those entities not on
the specified layers will be filtered out. These entities, for use
in modeling the surfaces, can be points, lines (such as
triangulation lines), 2D polylines (such as contours), and 3D
polylines (such as breaklines).
Inclusion and exclusion perimeters may optionally be specified to limit the volume calculation area on the grid. An inclusion perimeter should be used if there is a closed polyline for the limit of the disturbed area. Then the program internally generates grids of the surfaces from the entities on the corresponding layers and then calculates and reports the volume. The main disadvantage to this routine is that it doesn't have the special output options of Two Grid Surface Volumes such as Depth Contours.
Command: layervol
Pick Lower Left limit of surface area: pick lower left corner of grid
Pick Upper Right limit of surface area: pick upper right corner of
grid
You are then prompted to designate layers:
Select entities on layers of Existing surface.
select sample
object(s)
Select objects: Specify opposite corner: 3 found
Select objects: press
Enter to conclude selection.
Select entities on layers of Final surface. select sample object(s)
Select objects: Specify opposite corner: 10 found
Select objects: press
Enter to conclude selection.
Reading points ...
Select surface entities on corresponding layers.
Select objects: all
filters out those objects not on designated layers
85 found
Select objects: press
Enter to conclude selection.
Reading points ... 9396
Assigning grid values> 5300
Pass> 28 Null Z values left> 0
Writing grid file: C:\Documents and Settings\. .
.\USER\grid1.grd
Assigning grid values> 5300
Pass> 43 Null Z values left> 0
Writing grid file: C:\Documents and Settings\. .
.\USER\grid2.grd
Select the Inclusion perimeter polylines or ENTER for none:
select inclusion
perimeter
Select objects: 1 found
Select objects: press
Enter to conclude selection.
Select the Exclusion perimeter polylines or ENTER for none.
Select objects: press
Enter for none.
Reading cell> 5346
Pass> 28 Null Z values left> 0
Reading cell> 5346
Pass> 43 Null Z values left> 0
Pre-processing grid cells ....
Processing cells ...
Select point for color legend (Enter for None): press Enter
Pulldown Menu Location: Surface >> Volumes By Grid
Surfaces
Keyboard Command: layervol
Prerequisite: Entities that define both the base and final
surfaces.