Offsetting point events from LRS routes

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11-29-2022 01:52 PM
GraemeBrowning_Aurizon
Occasional Contributor II

I'm starting to work with LRS Point Events using ArcGIS Pro 3.0.2 and ArcGIS Enterprise 11.  My routes and point events are in a Geographic Coordinate System and have a field for Offset which is in meters. 

At the moment my point events are located on the routes (not offset from them) so I am wondering whether they need to be recreated so that they are located offset from them or whether the offsetting can only be achieved through how the point events are displayed?

I've been looking at Events data model—ArcGIS Pro | Documentation and Event referent fields but am keen to hear whether that is what I need before I put the effort into understanding and implementing them.

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4 Replies
AyanPalit
Esri Regular Contributor

@GraemeBrowning_Aurizon Recommend the following:

 

AyanPalit_1-1669817043662.png    AyanPalit_2-1669817083602.png

  • Note that adding Events by offset can be performed through the Event Editor web app. The option will be available in ArcGIS Pro-based Event Editing at a future release. It's simply another option to locate events in addition to the most common methods of
    • route and measure
    • coordinates
  • The Event referent fields must be present in Events data model—ArcGIS Pro | Documentation 
  • Enable Referent Fields
  • You are then ready to capture new Events using the offset method in Event Editor.  
Ayan Palit | Principal Consultant Esri
GraemeBrowning_Aurizon
Occasional Contributor II

That's very useful information and sounds like a powerful feature @AyanPalit .

However, when I'm talking about offsets, it is perpendicular offsets from the route, not offsets along the routes from existing point events or intersections.

In my case I am modelling Electrical Masts along a railway track that will be found a few meters away from the track with their location recorded in three fields: RouteName, Measure (along route) and Offset (perpendicular from route).

Can Event referent fields be used to do that too?

From Setting perpendicular offsets for event layers—Help | ArcGIS Desktop it looks like this could be done using an LRS in ArcMap but I'm not finding equivalent documentation for ArcGIS Pro.

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AyanPalit
Esri Regular Contributor

ArcGIS Location Referencing tools will allow capture of Events, inline with the route. You can get creative and symbolize the feature showing the offset using the perpendicular distance. Alternately, maintain the original location and a point snapped to the route. The snapped point will be managed as the LRS event and could be related to the offset point.

Ayan Palit | Principal Consultant Esri
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GraemeBrowning_Aurizon
Occasional Contributor II

It sounds like you are saying that ArcGIS Location Referencing tools will only allow capture of Events that are inline with the route.  Given that constraint, and that modelling the Electrical Masts is currently a relatively low priority for my work with Aurizon, I'll probably just record that their perpendicular offset field is currently difficult to take advantage of for either its display or instantiation as a point feature.

I'm currently unable to picture either of the workarounds you suggest.

  1. Symbolize the feature showing the offset using the perpendicular distance

Are you proposing that I use point symbology on the point event feature to do this?  If so, the point event knows what route it's near (and related to), how far along the route that nearest point is and how far the point event is from the route but how will that information get from the point event feature to the point renderer?

GraemeBrowning_Aurizon_0-1669862311820.png

If instead you're thinking of symbolizing a marker layer on the routes, then I know how to do that at regular intervals, and how to do that at the start and/or end of a route but not at irregular intervals read from a point event feature class related to it.  Also, all offsets seem to get specified in page units (pts) rather than map units (m).

Maintain the original location and a point snapped to the route

I can see how the snapped point can be managed as an LRS point event but not how to maintain the original location (aka the offset point).  Is that an ordinary point feature class which has an EventID to relate it to the point event feature class? If so, then I don't see how modifying a measure field value on a point in the point event feature class (which would slide it along the route) would be able to move a point in the ordinary point feature class parallel to the route at the offset distance.

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