LAS dataset point display differences between ArcMap and ArcScene

You can display LAS datasets as points in both ArcMap and ArcScene, and the vast majority of capabilities are the same in both viewing environments. There are, however, a number of capabilities that are different within the two applications that you should be aware of:

• Scalability/Point display limits
• Simple point symbology
• Viewing source file extents only
• Viewing an area of interest in full resolution

Scalability/Point display limits

ArcScene is a memory-based application and therefore has an upper limit to the number of point features it can display at one time. Given that this limit can vary significantly from machine to machine (based on hardware, operating system, and other such factors), you can choose to override the default setting based on how your machine is performing.

The default point limit is 12,800,000 million points, which is fairly conservative. While most machines should be able to handle that many points, it is possible for some machines to find this setting too ambitious. Also, it is worth noting that the point limit is defined for each LAS dataset layer separately, so be sure to make allowances when displaying multiple LAS datasets. That is, if you are displaying four LAS dataset layers, each with a point limit of 12 million points, there would be a total of 48 million points in the current view.

To increase the point limit for powerful machines or decrease it for less powerful machines, follow these steps:

1. Right-click the LAS dataset layer in the table of contents and click Properties.
2. Click the Display tab.
3. Change the Point limit property as required.
4. Click OK.

Another technique you can use to limit the number of points being displayed is the LAS dataset's filter settings. Here you can exclude points from being displayed based on their classification code or return number.

Learn more about the filter settings for LAS dataset layers

Simple point symbology

To display as many points as possible in ArcScene, only simple symbology is supported for LAS dataset points. This means that you cannot, for example, select a sphere, lamppost, or billboarded image to symbolize your lidar points; only size and color will be honored.

Also, the symbol size is always displayed in screen size and cannot be defined in real-world units, such as 2 meters wide. This means that as you zoom in closer to a group of lidar points within the 3D view, they will be displayed at the same size in pixels and may give the appearance of "separating."

Tip:

You can quickly tune the symbol size for all LAS dataset layers in the document, based on your current viewing distance, by pressing and holding the plus (+) and minus (-) keys.

There are two primary rendering options for lidar points: colored by point elevation or colored using a lidar attribute (such as the classification code or RGB color). Both of these options make it easy to define the color and size of the displayed points.

Displaying LAS datasets as points in ArcScene

Displaying LAS datasets as points in ArcMap

Note:

While it is technically possible to define a mixed renderer for LAS dataset layers, where both a point renderer and a surface renderer are used in the same layer, this is generally not recommended. Mixed renderers will decrease performance and cannot separate other properties (such as the filter) for each of the renderers. It is better practice to create individual layers for each rendering need.

Viewing source file extents only

For very large collections of LAS files, you might prefer to see only the 3D bounding boxes for your LAS dataset layer. This allows you to see the extent of your LAS data holdings without rendering any of the points. While this option is also available in ArcMap, the advantage of viewing this in ArcScene is that you also see the minimum and maximum vertical extents of each LAS file.

To view the source file extents for a LAS dataset layer, do the following:

1. Right-click the LAS dataset layer in the table of contents and click Properties.
2. Click the Display tab.
3. Check the Always display LAS file extents check box. Optionally, change the box outline color and enable the display of LAS file names.
4. Click OK.

Viewing an area of interest in full resolution

There are cases where LAS datasets can contain more points than can be rendered at one time.

When there are more points than can be rendered, ArcScene can do one of the following:

• View a randomly sampled subset of points (for context).
• Define an area of interest within which to see the lidar at full resolution (for data validation and investigation).

Defining an area of interest for your LAS dataset layers in ArcScene can be an expensive operation, as all the currently displayed points are discarded and a new set must be read from disk.

Learn more about defining an area of interest for a LAS dataset

Tip:

A shortcut to setting the full resolution location for LAS datasets is to press the F key and double-click in the view. You then reset the display back to the random subset by pressing R and double-clicking.

When there are more points than can be rendered, ArcMap can do one of the following:

• View a randomly sampled subset of points (for context).
• Use map scale to see the lidar surface at full resolution (for data validation and investigation).

Learn more about LAS dataset scalability