I have a task where I have plotted positions along an alignment (see red dots in images) and I need to plot two offset points (from the chainage locations) at varying distance parallel to the alignment (see image 2). I am not sure how to go about it.

enter image description here enter image description here

I have thought about:

  • working out the direction of the line and from that,
  • then working out what the offsets x,y should be using trigonometry,
  • create new points for the offset using the results of the trigonometry.

I was also thinking of:

  • creating a 1m buffer around the points,
  • using the buffer to clip the line into segments, then
  • copy the line parallel on the left and right side using the specified distances
  • then use feature vertices to points tool with mid as the point type to get the offset positions.

If there were only a few points, I would use the second method above, but unfortunately, I have hundreds.

I am familiar with Arcgis 10.1 and have a sound understanding of Arcpy and python.

  • I think linear referencing should enable to you to display point events like these at an offset distance.
    – PolyGeo
    Sep 25, 2015 at 6:43
  • Do you have offset distances in attribute table and are the lines regular lines or true curve?
    – Alešinar
    Sep 25, 2015 at 6:49
  • @Alešinar - the offsets are in a csv file. The lines will just be straight lines with a start and end point.
    – TsvGis
    Sep 26, 2015 at 3:59

1 Answer 1


I think you should investigate the Make Route Event Layer (Linear Referencing) tool:

Creates a temporary feature layer using routes and route events.

When the temporary layer is used (displayed on a map, or used by another geoprocessing tool), dynamic segmentation is performed.

and in particular its optional offset_field:

The field containing values used to offset events from their underlying route. This field must be numeric.

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