Slope Zone Analysis
This command calculates the surface area of a site in different
slope zone ranges. This command can use either a surface model
file, (.TIN, .GRD, or .FLT), or 3D Face drawing entities, which can
be generated by the Plot 3D Grid File command, the
Draw Triangular Mesh
command, or the Draw Triangulation Faces option of Triangulate
& Contour. For each slope zone, the 3D Faces can be
hatched with any hatch pattern, including the SOLID pattern, or
left empty with the NONE pattern. The command reports the area for
each slope zone. The Use Report Formatter option allows for
customized reports and different output formats.
This command can also generate contours of the slope zones based
on the calculated slope at each point of the 3D Faces. The slopes
can vary greatly between neighboring points. When contoured
directly, these slope data points produce incoherent contours.
Instead this routine applies a filtering algorithm that reduces the
noise. There is another option to output a grid file of the slope
values.
There are also options to specify inclusion and exclusion areas.
When inclusion areas are specified, only the slope area within the
inclusion polyline is calculated. Slope area within an exclusion
polyline are not included in the calculations. Inclusion and
exclusion areas are represented by closed polylines and must be
drawn prior to calling this routine. Without inclusion and
exclusion polylines, all the slope area of each selected 3D Face is
used.
Prompts
Slope Zone Options dialog
box. Choose whether to Draw Slope Zone Contours,
whether to Output Grid File of Slope, and Slope Format. Pick OK
Select surface model file.
Define Ranges dialog. Specify the slope zones, colors
and patterns from lowest to highest. Pick OK.
Select the Inclusion perimeter polylines or ENTER for none:
select perimeter(s) or
press Enter
Select the Exclusion perimeter polylines or ENTER for none:
select perimeter(s) or
press Enter
Report is generated.
Slope Report
Surface File: C:\scdev\data\SIMO2.grd
Average Slope: 21.6%
Minimum Slope: 0.0%
Maximum Slope: 81.7%
Horizontal Surface Slope Surface % of Average
Zone Range Area S.F. Acres Area S.F. Acres Total Slope %
-------------------------------------------------------------------------------
1 769,137.1 17.657 775,379.4 17.800 51.8 11.8
20.00%
2 583,761.4 13.401 607,257.9 13.941 39.3 28.2
40.00%
3 113,978.1 2.617 125,967.2 2.892 7.7 46.8
60.00%
4 18,494.6 0.425 22,407.7 0.514 1.2 68.3
-------------------------------------------------------------------------------
Total 1,485,371.1 34.099 1,531,012.2 35.147
If you choose to draw Slope Zone Contours, the Contour Options
dialog box is presented.
Note: If you choose to use Screen entities instead of a surface
model file, you are prompted whether to:
Apply hatch patterns to grid cells
[Yes/<No>]? and
Freeze grid layer after processing
[Yes/<No>]?
|
Surface contours |
|
3D Faces from a grid surface
model |
|
3D Faces created by Triangulate
& Contour with the Draw Triangulation Faces option |
|
Slope zone contours |
|
Slope zones that follow the
surface contours using the triangulation 3D Faces |
|
Hatched slope zone contours
created from the grid 3D Fac |
Pulldown Menu Location: Surface >> Slope
Analysis
Keyboard Command: szone
Prerequisite: Surface model file (.TIN, .GRD, or .FLT), or
3D Faces entities