About overlaying events

The Overlay Route Events tool can be used to overlay event tables. Line-on-line, line-on-point, and even point-on-point event overlays can be performed.

Learn more about the Overlay Route Events tool

Learn more about overlaying event data

To successfully overlay the input event table and overlay event table, both should be based on the same route reference. Otherwise, you can get erroneous results.

The output event table can contain either the intersection or the union of the input events. The union of the input events splits all linear events at their intersections and writes them to the new event table. The intersection of the input event tables writes only overlapping events to the output event table.

If either of the input tables contains point events, the output will always be a point event table. The new event table can be written to the workspace of your choice.

By default, the output event table contains a route identifier field, the measure fields, and all the input event attributes. You can choose not to write the event attributes. In this case, only the respective event layer's ObjectID field will be written to the output table. This field can be used at a later time to join or relate back to the original event attributes.

Learn more about the route identifier

When both inputs are line event tables, you can specify whether you want to keep zero length line events in the output table. These are events where the from- and to-measure are equal and are often created by the overlay process.