I added a LiDAR catalog to Express Server, but it's all one color! There is varied terrain in my dataset. Why does it all look the same?
This is a super common issue for a lot of datasets due to the way LiDAR is collected. Very often there will be a surface with, for example, an elevation range between 100 and 1500 meters. However there was a bird flying overhead (or a speck of dust or aerosols) that caused some of the LiDAR to bounce in unexpected ways and falsely report huge variations outside of this range. So even though you know the elevation of your dataset can only be between 100 and 1500 meters, you have data ranging from -45216 to 60481. By default Express Server will use these true values. Since RGB values can only be represented by a range of 0-255, it categorizes all these values into "buckets" so that -45216 through -44802 is 0 value, -44802 through -44388 is 2 value, and so forth. The problem is, because there is such a large range, all of the "real" elevation values get categorized into only one or a handful of buckets, so they all render as the same color. What we want to do is take this tiny range and stretch it so that it expands to fill out the full spectrum.
To do this, you'll need to know the true range of your data. You can do this using good known elevation values for your area or by running statistics on the file in your favorite GIS program. Then, select the catalog in Express Server Admin and select the LiDAR option on the left. Edit the Elevation Range minimum and maximum so that they accurately reflect the minimum and maximum values of your elevation data. You can also change the gradient in these options if you want something other than the default. Then save and publish in order to see the results.
If you're not sure what to use for the elevation range, you can play with this outside of Express Server by using our free GeoViewer available on the LizardTech website. Open the file in GeoViewer and go to UI Preferences. Under 3D settings you can override the static Z range of the map layers. We use GeoViewer a lot for purposes like this since it's very quick to see what sort of dynamic range settings work well without waiting for a full Express Server publish to go through. Sometimes it helps to slightly cut off very low or very high values, even if they are valid data, in order to give the rest of the map a better appearance.