{"id":2780072,"date":"2025-05-14T21:02:45","date_gmt":"2025-05-15T04:02:45","guid":{"rendered":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=2780072"},"modified":"2025-05-14T21:02:45","modified_gmt":"2025-05-15T04:02:45","slug":"classify-rail-points-in-mobile-lidar-point-clouds","status":"publish","type":"blog","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/3d-gis\/3d-gis\/classify-rail-points-in-mobile-lidar-point-clouds","title":{"rendered":"Classify rail points in mobile lidar point clouds"},"author":9692,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"_acf_changed":false,"_searchwp_excluded":""},"categories":[23771,22931,23351],"tags":[777362,24381,777712],"industry":[],"product":[36561],"class_list":["post-2780072","blog","type-blog","status-publish","format-standard","hentry","category-3d-gis","category-imagery","category-transportation","tag-feature-extraction","tag-lidar","tag-rails","product-arcgis-pro"],"acf":{"authors":[{"ID":9692,"user_firstname":"Jie","user_lastname":"Chang","nickname":"Jie Chang","user_nicename":"jchang","display_name":"Jie Chang","user_email":"JChang@esri.com","user_url":"","user_registered":"2019-06-26 21:13:09","user_description":"Jie is an Esri Software Product Engineer for 3D Analysis. He has over 10 years of experience in 3D, lidar, imagery, spatial analysis, deep learning, and Web GIS. Jie received his Ph.D. in Geospatial Information Sciences from the University of Texas at Dallas in 2011.","user_avatar":""},{"ID":7471,"user_firstname":"Alexander","user_lastname":"Gribov","nickname":"Alexander Gribov","user_nicename":"alexander-gribov","display_name":"Alexander Gribov","user_email":"agribov@esri.com","user_url":"","user_registered":"2018-03-21 18:21:20","user_description":"","user_avatar":""}],"related_articles":"","show_article_image":false,"card_image":false,"wide_image":false,"short_description":"This blog introduces the Rail Selection tool, explains how it works, and shares tips for using it effectively.","flexible_content":[{"acf_fc_layout":"content","content":"

ArcGIS Pro 3.5 introduces a Rail Selection tool that facilitates the interactive classification of points captured along rail tracks in mobile lidar point clouds. This blog article briefly describes how the rail selection process works and shares tips for using it effectively.<\/p>\n

 <\/p>\n

Before you begin<\/strong><\/p>\n

Mobile lidar point clouds can be extremely dense or stored in large files, which may negatively impact display and analysis performance. To improve efficiency, it\u2019s recommended to apply tiling and thinning<\/a> techniques to ensure an appropriate tile size and point density. Additionally, building pyramids<\/a> can significantly improve display performance. Dense rail data without pyramids may render much more slowly.<\/p>\n

 <\/p>\n

Use the Rail Selection tool<\/strong><\/p>\n

To use the Rail Selection tool, complete the following steps:<\/p>\n

    \n
  1. In the local scene, select a LAS dataset layer in the Contents<\/strong>.<\/li>\n
  2. On the Classification<\/strong> tab in the ribbon, in the Selection<\/strong> group, click Select > Rail<\/strong>.<\/li>\n<\/ol>\n

     <\/p>\n

    This opens the Rail Selection<\/strong> tool window, where you\u2019ll find primary and additional parameters with default values. While these defaults are generally sufficient, you may need to adjust them to accommodate data noise, track types, or more complex conditions, such as low-quality data, sharp curves, and at-grade crossings.<\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2780372,"id":2780372,"title":"RailSelectionUI","filename":"RailSelectionUI.png","filesize":18296,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/3d-gis\/3d-gis\/classify-rail-points-in-mobile-lidar-point-clouds\/railselectionui","alt":"Figure 1: User interface of the Rail Selection tool.","author":"9692","description":"","caption":"Figure 1: UI of the Rail Selection tool.","name":"railselectionui","status":"inherit","uploaded_to":2780072,"date":"2025-05-01 20:15:59","modified":"2025-05-01 20:25:37","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":294,"height":383,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI-213x200.png","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","medium-width":200,"medium-height":261,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","medium_large-width":294,"medium_large-height":383,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","large-width":294,"large-height":383,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","1536x1536-width":294,"1536x1536-height":383,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","2048x2048-width":294,"2048x2048-height":383,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","card_image-width":294,"card_image-height":383,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionUI.png","wide_image-width":294,"wide_image-height":383}},"image_position":"center","orientation":"horizontal","hyperlink":""},{"acf_fc_layout":"content","content":"

     <\/p>\n

      \n
    1. To start the selection, either double-click a rail point, draw a short line along the track, or sketch a small polygon around a rail segment.<\/li>\n<\/ol>\n

       <\/p>\n

      Upon completion of the selection, the count of selected rail points is displayed at the bottom of the view. A spinning wheel on the right indicates the progress of rendering the selection. Drawing may take a long time if a large number of points are selected.<\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2780382,"id":2780382,"title":"RailSelectionStatus","filename":"RailSelectionStatus.png","filesize":3727,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/3d-gis\/3d-gis\/classify-rail-points-in-mobile-lidar-point-clouds\/railselectionstatus","alt":"Figure 2: Status bar showing the number of selected rail points with a spinning wheel indicating drawing in progress.","author":"9692","description":"","caption":"Figure 2: The number of selected rail points is displayed in the status bar, and the spinning wheel indicates that drawing is in progress.","name":"railselectionstatus","status":"inherit","uploaded_to":2780072,"date":"2025-05-01 20:20:00","modified":"2025-05-01 20:24:53","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":321,"height":31,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus-213x31.png","thumbnail-width":213,"thumbnail-height":31,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","medium-width":321,"medium-height":31,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","medium_large-width":321,"medium_large-height":31,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","large-width":321,"large-height":31,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","1536x1536-width":321,"1536x1536-height":31,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","2048x2048-width":321,"2048x2048-height":31,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","card_image-width":321,"card_image-height":31,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/RailSelectionStatus.png","wide_image-width":321,"wide_image-height":31}},"image_position":"center","orientation":"horizontal","hyperlink":""},{"acf_fc_layout":"content","content":"

       <\/p>\n

      Once the wheel stops spinning, the selected points are rendered, and the spinning wheel reverts to a refresh button.<\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2780752,"id":2780752,"title":"SelectedRailPoints","filename":"SelectedRailPoints.png","filesize":310442,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/3d-gis\/3d-gis\/classify-rail-points-in-mobile-lidar-point-clouds\/selectedrailpoints","alt":"Figure 3: Selected rail points drawn in cyan.","author":"9692","description":"","caption":"Figure 3: Selected rail points are drawn in cyan. The spinning wheel has reverted to the refresh button, indicating the drawing is complete. Data courtesy of Esri India.","name":"selectedrailpoints","status":"inherit","uploaded_to":2780072,"date":"2025-05-01 22:30:46","modified":"2025-05-01 22:37:23","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":524,"height":594,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints-213x200.png","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","medium-width":230,"medium-height":261,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","medium_large-width":524,"medium_large-height":594,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","large-width":524,"large-height":594,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","1536x1536-width":524,"1536x1536-height":594,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","2048x2048-width":524,"2048x2048-height":594,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints-410x465.png","card_image-width":410,"card_image-height":465,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SelectedRailPoints.png","wide_image-width":524,"wide_image-height":594}},"image_position":"center","orientation":"horizontal","hyperlink":""},{"acf_fc_layout":"content","content":"

       <\/p>\n

      After you\u2019ve verified that the selected points correctly represent rails, you can assign them a class code (typically 10 for rail).<\/p>\n

        \n
      1. Go to the Interactive Editing<\/strong> group on the Classification<\/strong>.<\/li>\n
      2. From the Classification Code<\/strong> drop-down list, select 10 Rail<\/strong>.<\/li>\n
      3. Click the Apply Changes<\/strong>.<\/li>\n<\/ol>\n

         <\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2780772,"id":2780772,"title":"SetRailClassCode","filename":"SetRailClassCode.png","filesize":10673,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/3d-gis\/3d-gis\/classify-rail-points-in-mobile-lidar-point-clouds\/setrailclasscode","alt":"Figure 4: Assign class code to the selected rail points.","author":"9692","description":"","caption":"Figure 4: Interactive editing: Class code 10 is assigned to the selected points","name":"setrailclasscode","status":"inherit","uploaded_to":2780072,"date":"2025-05-01 22:38:29","modified":"2025-05-01 22:40:26","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":474,"height":167,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode-213x167.png","thumbnail-width":213,"thumbnail-height":167,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","medium-width":464,"medium-height":163,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","medium_large-width":474,"medium_large-height":167,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","large-width":474,"large-height":167,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","1536x1536-width":474,"1536x1536-height":167,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","2048x2048-width":474,"2048x2048-height":167,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","card_image-width":474,"card_image-height":167,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/05\/SetRailClassCode.png","wide_image-width":474,"wide_image-height":167}},"image_position":"center","orientation":"horizontal","hyperlink":""},{"acf_fc_layout":"content","content":"

         <\/p>\n

        Understand the rail points selection process<\/strong><\/p>\n

        The rail selection process begins by identifying seeds. The tool evaluates the selected points and determines whether they qualify as seeds.<\/p>\n

        Once the seeds are established, the tool constructs an active set of points that functions as a moving window, which searches for nearby points and adds those that are evaluated as rail. When the moving window exceeds the specified rail moving length, it splits into two windows that then move in opposite directions along the rail. As each window advances, it searches for candidate rail points within a specified search radius from the front of the window.<\/p>\n

        Points are iteratively added to the active set if they meet all of the following criteria:<\/p>\n