Identify elevations, based on FG profiles in horizontal alignments.

Usage:

The ELA command runs as a continuous loop. To exit the command, select the "Quit" option from the dialog box, or press "ESC".

In the dialog box, select the alignment and FG profile to use to calculate the grade. The other values in the dialog box are as follows:

Grading Offset

This is a vertical datum adjustment applied to the profile grade. In the diagram below, the datum adjustment would be the sum of y + z.

Grade % and Crown

This is the grade, keyed in as a percentage. It is indicated by g in the diagram below. The value should be positive if the grade increases from left side to right side, and negative if the grade decreases from left side to right side. Check the "Crown" box to indicate a crown. For example, a typical roadway would have a value of "-2" for grade percentage, and would have the "Crown" box checked.

Grading Offset

This is the distance between the selection point and the grading point. This distance is indicated by x in the diagram below.

The grade g% is projected out to the grading point from the profile line. In the example below, the user picks on the top back of curb. The grade at this point is a set distance above the lip of the curb (the grading point).

If the selection point is further from the profile line than the grading point, then x should be positive. This is true, even on the left side of the profile line. This lets you select points on both sides of a standard road without changing the settings.

See Also:

l NOTCH

Create lines on equally-spaced stations along an alignment.

l PGRD

Create elevated COGO points along a polyline, line, arc, or spline, at any offset, and straigh-graded between spot elevations. Points are equally-spaced between grade breaks and horizontal breaks.

l PT2ALIGN

Change elevation of selected COGO points to match an alignment FG profile.

l XGRD

Grade COGO points based on cross-slopes calculated from selected points and an alignment FG profile.