Equate OB

This determines when in the calculation process the Proposed Out of Bounds elevations are set to the Existing elevations. The default value is After Calculating Proposed.

When a project boundary is determined by the junction of proposed and existing contour lines, the Proposed OB elevations can be set after the proposed elevations are calculated. This allows the proposed and exisiting surfaces to be calulated simultaneously.

When the project boundary is not determined by the junction of proposed and existing contour lines. the Proposed OB values should be set prior to calculating the proposed surface. These elevations are then used in determining the proposed elevations at the project boundary. In this case, the existing surface must be well defined outside the project boundary. This is accomplished by taking off contour lines and point elevations outside the boundary.

In summary, if the proposed elevations or cut and fill appear to be in error near the project boundaries, try calculating with this option set to Before Calculating Proposed.