topic Re: Loading Routes from M aware FC in Roads and Highways User Group (RHUG) Questions

Loading Routes from M aware FC

CameronCole — Tue, 07 Dec 2021 19:43:20 GMT

I am loading Routes into the LRM that M aware and have specific M values at vertices for calibration.

However, when I load the data the vertices stay in the same X and Y locations but the M values get re-calculated.

When loading the data I am using M on route 2d, Miles.

How do I get the M values from the original M aware FC to come through as the M values in the LRM? Or how do I update the M values to match after the fact?

Re: Loading Routes from M aware FC

NathanEasley — Wed, 08 Dec 2021 00:05:34 GMT

Hi Cameron,

Roads and Highways will interpolate and populate M values on your routes based on the nearest upstream and downstream calibration points. Depending on how many and where you placed the calibration points (or equivalent) in your previous linear referencing solution, the interpolation could be different in Roads and Highways if the calibration points are in different locations or have different measures.

If you find the M values at specific locations have changed from what you expect, you can add calibration points at those locations to "lock in" a specific measure at a specific location along a route.

Nathan
ArcGIS Roads and Highways team

Re: Loading Routes from M aware FC

CameronCole — Wed, 08 Dec 2021 15:22:03 GMT

Nathan,

Thank you for the explanation. What I am thinking about doing is converting all of the vertices of the original M aware FC into points and then loading them into the calibration points layer. Does that seem like a solution? I can't really see a way to update the entire state manually efficiently or pulling only specific vertices to become calibration.

The staff has already done all of the "calibration" on the FC, setting M values specifically at intersections and known locations. Then when I loaded it into R&H that all went away, I assumed when setting M on Route 2d that meant it would keep the M values that were on the route.

Re: Loading Routes from M aware FC

NathanEasley — Wed, 08 Dec 2021 21:01:07 GMT

Yes you could do that, but I'd recommend also looking at whether you need a calibration point at each vertex. Adding a few strategic calibration points along a route can help narrow down the interpolation, especially if you can determine where the Ms on your source route diverge from the interpolated measures and geometric length of the poyline that Roads and Highways utilizes.

Nathan
ArcGIS Roads and Highways team