Profile By Slope From Element translates longitudinally and cannot be trusted

I find on my own computer and on my trainee's computer--both running Power Geopak SS4 .872--that when I project a profile from one plan element to another via Project Profile To Element and when I project a profile from one plan element to another via Profile By Slope From Element (even using a zero slope), one of them is longitudinally translated from the other and reminds me of how a sine wave might look when you have two of them at different phases.

How do I know that the Project Profile To Element is correct? If I have a corridor that features a -2% pavement slope at 12 feet to the right, I get a 3D linear feature. If I project that linear feature to a collinear plan line, I get a given elevation which parallels the projection using Project Profile To Element. If I project the centerline to this collinear plan line using Profile By Slope From Element, I get a translated profile.

After a few quick steps, I found that it has less to do with the template drop length (no matter the length of the template drop, whether it begins at the beginning of alignment or anything), it doesn't cause the problem.

It seems to have to do with the distance between the beginning of the alignment and the beginning of the alignment's profile. If my alignment's profile begins at station 0, this problem doesn't exhibit itself. If my alignment's profile begins at station 1+00 (or 2+00), the EP profile begins at station 2+00 (or 4+00) at the elevation that would be appropriate if it was at station 1+00 (or 2+00) as it should be. 

Anyone know if this affects .845? I have no memory of seeing this problem in that version. I have confirmed with another computer in our office that this does not affect .845, but it affects Geopak SS4 .872 which I and my trainee both have.

Parents Reply
  • We (Illinois DOT) are experiencing the same issue.  When using the project profile by variable slope tool, the profile comes in almost the exact distance from the beginning of the alignment to the beginning of the active profile we are projecting.

    The screenshot below shows the location selected during projection (1027+98.75-1028+28.75), where the profile should come in (the first part of the purple profile), and where the profile comes in (the highlighted line & seen in element information)

    I can tell the user to "get pretty close" by using element information & subtracting the difference in alignment & active profile from the Start Reference Distance and End Reference Distance but it seems like this is still a defect.

Children