LP360 includes tools to automatically extract a rail alignment (centerline) feature as a polyline as well as classify “top of rail” from LAS files derived from Laser Intensity Detection and Ranging (LIDAR) points. This feature is implemented as a semi-automated Point Cloud Task (PCT) and is available in the Advanced version of both LP360 for ArcGIS® and LP360 (the standalone version of LP360 for Microsoft Windows®). While introduced some time ago into LP360, this PCT has been improved with the recently released version 2017.1 of LP360/LP360 for ArcGIS.
We used to recommend using this PCT within LP360 for ArcGIS since we had only rudimentary feature editing tools in LP360 prior to the 2016.1 release of LP360. Now, with the advanced tools of LP360 2017.1, LP360 is a much faster and more flexible editing environment for LIDAR extracted features than is ArcGIS.
We have made several enhancements to the rail extractor PCT in 2017.1:
- Better extraction from “thinner” data such as helicopter LIDAR
- An experimental capability of spanning sections of track where the rails are not above the rail bed (for example, at-grade intersections)
The alignment is collected as a set of 3-dimensional polyline features in Shape file format. The top of rail points have their Classification Attribute set to the class number being used for rail (10 is the American Society for Photogrammetry and Remote Sensing, ASPRS, standard). The rail centerline elevation is at the top of rail since this is the convention used by most American rail lines performing data extraction in support of the Positive Train Control initiative.
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