The following steps show how to generate a GeoTIFF DEM and split the resultant file into separate bands.
Generate the DEM
- Open up a text editor. Type in the following JSON text. Save the text into a file e.g. pdal_dtm.json
Note: the JSON pipeline text will do the following:
(a) Load in a LAS file e.g. autzen.laz
(b) Filter away non-ground classified point
(c) Write only the mean Z values to a GeoTIFF file dem.tif with a resolution of 10 meters - Open up the OSGeo4W Command Prompt.
The Command Prompt appears. - Type in the PDAL command to process the pipeline. Run the command.
C:\> pdal pipeline pdal_dtm.json
The GeoTIFF file dem.tif is generated.
Splitting the bands
Displaying the resultant dem.tif containing only the mean Z band in QGIS will show something resembling a grayscale terrain with masked areas, as shown in the screenshot below.
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However, displaying the resultant GeoTIFF in Global Mapper will show a black rectangle, as shown below, due to the presence of an alpha channel. This need to be removed for proper interpretation of the elevation data.
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To split the bands, do the following:
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