Latest Contributions by JeffreySwain

Lidar data is become increasingly available and there are likewise new tools to analyze and display the data. LAS is the public file format for the interchange of three dimensional point cloud data between data users. LAS information can be downloaded and has a file extension of *.las. The LAS Dataset was created in order to grant the ability to utilize LAS data quickly in ArcMap. However, with the advent of the new format, new questions are raised, including what types of analysis, geoprocessing tools and toolbar buttons can be used on a LAS dataset. The ArcGIS 10.1 help documentation lists all of the tools that can be used on a LAS dataset within ArcToolbox and on the 3D Analyst toolbar, all with only a few small steps to enable them. What small steps am I referring to? Full Extent of the LAS Dataset with the Tools greyed out. The ArcGIS 10.1 help on interactive toolbar tools for LAS datasets identifies one such step: However, the tools are not always active when working with LAS datasets and the 3D Analyst toolbar tools. The 3D Analyst toolbar tools are only available when a LAS dataset is displayed as a full resolution triangulated surface. A full resolution surface is indicated in the table of contents when 100% of points are being used to construct the triangulated surface. When the LAS dataset is displayed as a point set the tools will be disabled. What does 'full resolution' mean? According to the ArcGIS help on the topic, the definition is, "the scale threshold used to control when the LAS dataset will render itself without thinning, using 100% of the LAS points." So once you have modified the settings or zoomed in far enough to see 100% of the LAS points, you can use all the tools in the 3D Analyst toolbar, right? Almost. The final step is to choose the Elevation option from the Display As TIN options on the LAS dataset. Once you make that selection, you should see the LAS dataset appear in the drop-down for the 3D Analyst toolbar and the tools should become active. Now you can create the profile graph or generate a 3d feature just as you would with a normally recognized surface in ArcMap. References Additional information on Lidar and LAS files: ASPRS PAD Lidar Committee ArcGIS Help 10.1: What is lidar data? Additional blogs on LAS dataset: New 3D Analyst geoprocessing tools and enhancements at 10.1 Your Enhancements in Action: LIDAR - Viewing and Editing *.las Files Jeff S. – Senior Support Analyst ... View more