Displaying LAS datasets in ArcScene at full resolution

A LAS dataset is a simple container definition of one or more lidar (LAS) files that represent a single, logical unit. For example, you might have several thousand LAS files that together cover an entire administrative area or perhaps just a few LAS files for a specific study area.

In cases where the LAS dataset contains very large numbers of points, it may not be possible for ArcScene to display the lidar at full resolution. In these cases, by default, the LAS dataset layer will render a randomly sampled subset of the points across the entire view.

You can, however, choose to display an area of interest (AOI) in full resolution. When displaying a LAS dataset layer in this mode, ArcScene will display every point within the given region before attempting to render any other points. The result is an area guaranteed to contain all available lidar points, with the rest of the view displaying a subset of the remaining points.

Setting and releasing the full-resolution location

While it is very easy to define an area of interest for your LAS dataset layers, it can potentially be an expensive operation—all the currently displayed points and surfaces need to be reread from disk and added back into the view. You should only define or update a full-resolution area of interest when it is needed.

To set a full resolution area of interest for all LAS dataset layers in the view, do the following:

1. Click the Navigation button on the Tools toolbar.
2. Press and hold the F key.
3. Double-click on the view.

A full-resolution area around the point is automatically calculated and populated. The extent is shown with a red bounding box and its size is based on the point density within your LAS files.

Airborne lidar with an area (enclosed within the red bounding box) shown in full lidar resolution (Data courtesy of Optech)

Note:

• You will need to click on a point within the 3D view when you double-click.
• Once the location is selected, ArcScene will automatically add the lidar points into the scene until the point budget has been reached.
• Pressing the B key toggles between box display.

To release the area of interest (and return to an evenly spaced view of your LAS dataset points), do the following:

1. Click the Navigation button on the Tools toolbar.
2. Press and hold the R key.
3. Double-click on the view.

Defining the percentage of points to use for full resolution

By default, 90 percent of the point budget for a LAS dataset layer is used to populate the full-resolution area of interest, with the remaining 10 percent distributed randomly across the rest of the LAS data extent. This allows you to see the complete coverage of your LAS data even while viewing a subset of it in full resolution.

You can, however, choose to modify the allocation percentage for your LAS dataset layer. For example, you might want to use the entire point budget for the high-resolution area or spread the budget evenly between the full-resolution and data-context areas. As you reduce the percentage value, and therefore the budget of points available for the area of interest, the area will also be reduced in size.

To change the percentage of the LAS dataset point budget to be shown at full resolution, follow these steps:

1. Right-click the LAS dataset layer in the ArcScene table of contents and click Properties.
2. Click the Display tab.
3. Move the Point Density slider as required.
   Note:

   Increase the percentage to use more points to define the area of interest. Decrease the percentage to use fewer points to define the area of interest.

4. Click OK.

Adjust the Point Density slider to control the number of points to be displayed at full resolution within the area of interest.