FAQ

  • How do you pronounce PDAL?

    The proper spelling of the project name is PDAL, in uppercase. It is pronounced to rhyme with “GDAL”.

     

  • Why do I get the error “Couldn’t create … stage of type …”?

    In almost all cases this error occurs because you’re trying to run a stage that is built as a plugin and the plugin (a shared library file or DLL) can’t be found by pdal. You can verify whether the plugin can be found by running pdal --drivers

    If you’ve built pdal yourself, make sure you’ve requested to build the plugin in question (set BUILD_PLUGIN_TILEDB=ON, for example, in CMakeCache.txt).

    If you’ve successfully built the plugin, a shared object called

    libpdal_plugin_<plugin type>_<plugin name>.<shared library extension>
    

    should have been created that’s installed in a location where pdal can find it. pdal will search the following paths for plugins: ., ./lib, ../lib, ./bin, ../bin.

    You can also override the default search path by setting the environment variable PDAL_DRIVER_PATH to a list of directories that pdal should search for plugins.

     

  • Why do I get the error ``Unable to convert scaled value … “

    This error usually occurs when writing LAS files, but can occur with other formats.

    Simply, the output format you’ve chosen doesn’t support values as large (or small) as those that you’re trying to write. For example. if the output format specifies 32-bit signed integers, attempting to write a value larger than 2,147,483,647 will cause this error, as 2,147,483,647 is the largest 32-bit signed integer.

    The LAS format always stores X, Y and Z values as 32-bit integers. You can specify a scale factor to be applied to those values in order to change their magnitude, but their precision is limited to 32 bits. If the value you’re attempting to write, when divided by the scale factor you’ve specified, is larger than 2,147,483,647, you will get this error. For example, if you attempt to write the value 6 with a scale factor of .000000001, you’ll get this error, as 6 / .000000001 is 6,000,000,000, which is larger than the maximum integer value.

     

  • Why am I using 100GB of memory when trying to process a 10GB LAZ file?

    If you’re performing an operation that is using standard mode, PDAL will read all points into memory at once. Compressed files, like LAZ, can decompress to much larger sizes before PDAL can process the data. Furthermore, some operations (notably DEM creation) can use large amounts of additional memory during processing before the output can be written. Depending on the operation, PDAL will attempt operate in stream mode to limit memory consumption when possible.

     

  • What is PDAL’s relationship to PCL?

    PDAL is PCL’s data translation cousin. PDAL is focused on providing a declarative pipeline syntax for orchestrating translation operations. PDAL also supports reading and writing PCL PCD files using readers.pcd and writers.pcd.

    See also

    PCL describes PDAL and PCL’s relationship.

     

  • What is PDAL’s relationship to libLAS?

    The idea behind libLAS was limited to LIDAR data and basic manipulation. libLAS was also trying to be partially compatible with LASlib and LAStools. PDAL, on the other hand, aims to be a ultimate library and a set of tools for manipulating and processing point clouds and is easily extensible by its users. Howard Butler talked more about this history in a GeoHipster interview in 2018.

     

  • Are there any command line tools in PDAL similar to LAStools?

    Yes. The pdal command provides a wide range of features which go far beyond basic LIDAR data processing. Additionally, PDAL is licensed under an open source license (this applies to the whole library and all command line tools).

    See also

    Applications describes application operations you can achieve with PDAL.

     

  • Is there any compatibility with libLAS’s LAS Utility Applications or LAStools?

    No. The the command line interface was developed from scratch with focus on usability and readability. You will find that the pdal command has several well-organized subcommands such as info or translate (see Applications).

     

  • I get GeoTIFF errors. What can I do about them?

    (readers.las Error) Geotiff directory contains key 0 with short entry
    and more than one value.
    

    If readers.las is emitting error messages about GeoTIFF, this means the keys that were written into your file were incorrect or at least not readable by libgeotiff. Rewrite the file using PDAL to fix the issue:

    pdal translate badfile.las goodfile.las --writers.las.forward=all