Now that your dataset is rendered as a surface, there are additional display settings you can customize. However, a number of these display properties that are important when viewing LAS datasets as a surface are different between ArcScene and ArcMap:
- Surface resolution display limit
- Choice of surface symbology
- Viewing an area of interest in full resolution
Surface resolution display limit
ArcScene is a memory-based application and therefore has an upper limit to the complexity of the surface that it can display. 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 surface resolution is limited to 800,000 points in both ArcScene and ArcMap, which is fairly conservative. While most machines should be able to handle a surface of that resolution, it is possible for some machines to find this setting too ambitious. Also, it is worth noting that the surface point resolution 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 five LAS dataset layers as surfaces, each with a resolution of 800,000 points, there would be a total of 4 million points used for surfaces in the current view.
Also, unlike ArcMap, which reloads points every time you zoom in or out, ArcScene will only load the applicable points when the layer is first loaded (or reloaded when important layer properties are changed). This means that, unless the number of points is less than the budgeted limit, the surface view in ArcScene is at a static level of detail that does not include all the points.
To increase the point limit for powerful machines or decrease it for less powerful machines, follow these steps:
- Right-click the LAS dataset layer in the table of contents and click Properties.
- Click the Display tab.
- Change the Point limit property as required.
- Click OK.
Another technique you can use to limit surface complexity being displayed is the LAS dataset's filter settings, where you can exclude points from being displayed based on their classification code or return number. For example, a LAS dataset containing 10 million points might only have a few million points that are classified as bare earth.
Choice of surface symbology
All the standard TIN renderers, such as elevation, slope, and aspect, are available for the LAS dataset layer when rendering it as a surface. However, it is worth noting that the performance cost for each of these renderers is not the same.
The rule of thumb is the simpler the symbology, the lower the cost of display. For example, the Faces with the same symboloption will have a lower performance cost than the Face elevation with graduated color ramp renderer. If you are experiencing poor performance when displaying your LAS dataset as a surface in ArcScene, it might be worth revisiting your symbology options. For example, to gain interactive performance for a particular document, you may need to stop rendering your LAS dataset with both a face renderer and a contour renderer.
Viewing an area of interest in full resolution
When working with LAS datasets that contain more points than can be included in a surface at one time, you can either view a randomly sampled subset of points (for context), or define an area of interest in ArcScene within which to see the lidar surface at full resolution (for data validation and investigation). In ArcMap, you can view randomly sampled subset of points (for context), or use map scale to see the lidar surface at full resolution (for data validation and investigation).
Defining an area of interest for your LAS dataset layer in ArcScene can be an expensive operation, as the currently displayed surface is discarded and a new one must be created from an updated set of points pulled from disk.
In ArcMap, the surface points are thinned based on the current display scale. ArcMap reloads the data every time you zoom or move throughout the display. Each time the scale changes, or the display is panned, only the data necessary for display within the current extent are accessed, triangulated, and displayed on screen. The LAS points are thinned randomly based on the extent and number of potential points to display.Learn more about LAS dataset scalability