Slope Report

This command calculates the sloped surface area, average slope and average elevation on a site. The surface can be defined by a surface model file, (.GRD, .TIN or .FLT), or generated from 3D entities on the screen. Sloped area information is useful to compute seeding quantities for hillsides, for example.

For the screen method, the surface is modeled from the user-selected entities such as contour polylines. Besides the surface entities, a perimeter polyline is used as the inclusion area for the slope report.  If the perimeter polyline is on the PERIMETER layer, the command will locate it automatically.

For area reports, there are options to specify inclusion and exclusion perimeters. When inclusion perimeters are specified, only the area within the inclusion perimeters is calculated. The area within exclusion perimeters is not included in the calculations. Inclusion and exclusion perimeters are represented by closed polylines and must be drawn prior to running this routine.

Prompts

For Area report using a File:
Slope report by area or two points [Area/<Points>]? A for Area
Source of surface model (<File>/Screen)? F for File
Select surface model file.
Select the Inclusion perimeter polylines or ENTER for none: pick any inclusion polylines
Select the Exclusion perimeter polylines or ENTER for none: pick any exclusion polylines
Note: If the surface model file is a grid file (.GRD), you are prompted whether to extrapolate the grid to full grid size.

For Area report by Screen method:
Slope report by area or two points [Area/<Points>]? A for Area
Source of surface model (<File>/Screen)? S for Screen
Ignore zero elevations (<Yes>/No)? press Enter
Select surface entities and perimeter.
Select objects: pick the objects
If no polyline is found on layer PERIMETER, you are prompted to: Select Pond/Pit perimeter polyline.
The Make 3D Grid File dialog is presented.  Pick OK.

Select the Inclusion perimeter polylines or ENTER for none: pick any inclusion polylines
Select the Exclusion perimeter polylines or ENTER for none: pick any exclusion polylines

For Points method:
Slope report by area or two points [Area/<Points>]? P for Points
Select surface model file.
Pick first point:
Pick Second point:
The slope report is displayed on the command line for the 3D vector, projected on the surface, defined by those 2 picks.

Point 1: 5119.646,5640.322,98.979
Point 2: 4951.964,6022.419,135.546
Horiz Dist: 417.27 Slope Dist: 418.87 Elv Diff: 36.57
Slope: 8.76 Ratio: 11.41:1

Pulldown Menu Location: Surface >> Slope Analysis
Keyboard Command: sarea
Prerequisite: A surface file or screen entities of the surface.