I have a DEM built from LiDAR data and the file extension is .tif. When I open this file in ArcMap it seems to be a shaded relief DEM (see the screenshot below).
It happens I want to visualize the DEM colored by elevation. How should I proceed?
[GIS] DEM out of a shaded relief LiDAR
arcgis-desktopdemhillshadelidarvisualisation
Related Solutions
You often see this type of behavior with strange min/max values in ArcGIS when a raster does not have statistics calculated or is in certain formats. It is more of a display issue than data integrity. I would convert your raster from its current format to a native ESRI grid format or img. You can do this by right clicking on the raster in ArcCatalog and selecting Export > Raster to Different Format... You can also right click on a raster and select calculate statistics... Working with rasters in other formats can yield unpredictable results.
To fix the differences along tiles just mosaic the source DEM's together before calculating a shaded relief. The correct tool for this is Arctoolbox > Data Management Tools > Raster > Raster Dataset > Mosaic to New Raster
You already have a DEM; there is no need for you to create one. The DEM is contained within your files, i.e. you have two copies of the DEM, one contained within an ArcGIS ASCII raster and the other within a GeoTIFF. These are simply file formats that contain the raster data that is your DEM. One of the most common formats for a terrain model is as a regular grid (raster) in which each cell in the grid contains a single elevation value. When I imported your Arc ASCII file into another GIS (I don't have ArcGIS on my machine) this is what it looked like:
I suspect that this is what you refer to as 'a grayscale flat plane', but I assure you that this is a DEM. If I change the colour ramp (palette) used to render the raster and combine it with a hillshade image derived from the elevation data, this is what it looks like:
Granted this is one of the most boring DEMs that I have come across, having worked with DEM data for my entire career, but it is nonetheless a proper DEM. It's just that there isn't much interesting topographically speaking about the data. Also, I can tell from the hillshade image that it was interpolated through a TIN algorithm, which may not have been altogether successful in this particular application depending on exactly what it is you want to do with the DEM.
If you have multiple DEM tiles like this one, then you will need to stitch them all together into a single raster, a process that is known as Mosaicking. Then what you do with your mosaicked DEM depends entirely on your particular application. Perhaps you want to extract stream networks or watershed. Maybe you want to use it to model contamination of surface waterbodies or to measure the spatial pattern of landscape visibility. Maybe you just want to create a cool looking 3D visualization of the terrain...something that you could use the ArcGIS 3D Analyst for if you have the licence for that. There is a vast number of things that DEMs can be used for...welcome to the exciting field of geomorphometry!
Best Answer
What you have is a hillshade surface built from a LiDAR point cloud. According to ESRI:
So each pixel of your .tif raster has an hypothetical illumination value given a reference position of the sun.
What you want is a DEM (a bare-earth surface) where each pixel in the raster represents an elevation value. As stated by Jeffrey Evans it is not possible to backwards converting hillshade values into elevation.
The best alternative would be to try acquiring the raw LiDAR data and built the DEM from scratch. For example, see:
Determining bare earth DEM from unclassified LAS file?