how to designate right and left side of a river centerline?

[JoannaWhittier]

I am converting XY coordinates to SN coordinates (orthogonal curvilinear coordinates) for points within a stream. The purpose is basically to straighten out the stream to take into account the linear nature. One end of the riverline is set as S=0, N=0. S increases with the length of the river centerline. N increases with distance from the centerline. N values are positive on the right side of the line and negative on the left side. I could highlight all points on the right or left side to manually assign these .... but I have thousands of points. Is there a way to automate the assignment for whether the points are on the right or left side of a centerline?

[KyleGonterwitz]

Linear Referencing!  

[KyleGonterwitz · Accepted solution]

1. create a route (create route) from your stream centerline using begin and end measures of 0 and the length of the river centerline.

2.  locate the xy points along the route (locate features along route) to make an event table of the route reference coordinates and offsets.  Offsets should be negative and positive for right and left and there is an option to set which is right and left.

3.  To review the coordinates make a route event layer using the linear referenced route coordinates and the route reference.

There are several options to each of these tools so if you find something doesn't work how you expected, try another option.