I have a DEM built from Lidar data and bathymetry survey points for a river which flows on the DEM surface.
My understanding is that Lidar data is not able to capture bathymetry under the river flow.
How can I stitch survey points and DEM together and build a new DEM?
Best Answer
If your bathymetric data are current in the form of survey points then you should interpolate them onto a raster grid of the same resolution and extent as your LiDAR data. There are several methods for interpolating these points available in ArcGIS such as splining, IDW and kriging. The most appropriate method to use will depend on your data characteristics (e.g. density and accuracy) and on the application. Now, I assume that the LiDAR raster DEM has NoData values for the areas within the river. This is usually the case for LiDAR. You can use the CON to create a conditional evaluation statement such that the output raster grid is assigned the LiDAR DEM elevation value for all cells where the LiDAR DEM has a non-NoData value (i.e. a valid value) and the bathymetric DEM value for all cells where the LiDAR DEM is equal to the NoData value. It's essentially an IF-THEN-ELSE where IF LiDAR_DEM != NoData assign output LiDAR_DEM value, else assign output Bathymetric_DEM value.