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.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik2Woiv-79ZMj2J6OGDCc4P0YUQ6dDdZ_Db88uq0PMD2tqJH8tnUDDva2aQq-5Sx05o5NinmIOUGSmFfSnCrZ13pobYd1ZMcPFBSGGd_Cb-rnmg9U1t-jqaJz6k_pzpN9RohZf7u0Vpg/s320/pdaldem02.png)
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.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiD8OWgT2zmzsl4ZvqgdqdnYkFAj2jJHCV0UA8YJm4Sg96i4UsT8S7zQgxRRwUR0cG6xgW7t88nSI8sLiP7wuzTcIwiu5LbvWooKbxDrAFMA3Pp4L9nG7m4xl5-TrjJfdf526ve358UA/s320/pdaldem04.png)
To split the bands, do the following:
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