PROJ lib integration¶

PROJ is a generic coordinate transformation software that transforms geospatial coordinates from one coordinate reference system (CRS) to another. This includes cartographic projections as well as geodetic transformations. PROJ is used and utilized in LAStools (las2las) to transform LiDAR data between various coordinate reference systems and to retrieve detailed
represenations and information about CRS (lasinfo).

Key features include:

Transformation of point coordinates between different CRS.
Conversion and representation of CRS in various formats (EPSG, WKT, PROJ string, PROJJSON).
Retrieval of metadata such as ellipsoids, axes, and datum information related to a CRS.

The integration of the PROJ library provides a flexible and powerful means to perform geodetic transformations directly within LAStools.

The source code for the PROJ library is available at https://github.com/OSGeo/PROJ.

Installing the PROJ Library¶

To use the PROJ library in LAStools, it must be installed on your system (possibly via QGIS or OSGeo4W or Conda). Please note: This software requires PROJ version 9.0.0 or later. If the PROJ library is not already installed, here are several methods to install it (We recommend using the default standard installation paths):

Package Managers¶

OSGeo4W: Use this Windows-specific package manager to install PROJ.

Download [OSGeo4W setup] - https://trac.osgeo.org/osgeo4w/
Start the installer ‘osgeo4w-setup.exe’ and select mode: Advanced Install
In the package selection window: ‘Commandline_Utilities -> proj’ or search for proj using the search bar and select it.
Finish installation

Conda: Use this Cross-Platform package manager to install PROJ with the following command:

conda install -c conda-forge proj And for the PROJ data:

conda install -c conda-forge proj-data

If a warning appears in Linux stating that the library was found via the Conda installation but could not be loaded, this is usually because the dynamic loader finds the incompatible system libraries first. Using export LD_LIBRARY_PATH=~/miniconda3/lib:$LD_LIBRARY_PATH ensures that the Conda libraries and their dependencies are loaded first.
Note that in this case, the environment variable only applies to the current shell session.

The environment variable only applies to the current shell session.

Docker: Get the Docker image with:

docker pull osgeo/proj

QGIS Installation¶

By installing QGIS, you automatically get the PROJ library installed and configured.

Windows:

Download the QGIS installer from the [QGIS setup] (https://www.qgis.org/download/).
Run the installer and follow the installation steps.
Once QGIS is installed, the PROJ library will be available.

Linux: Debian/Ubuntu: QGIS can also be installed on Linux distributions, which will include the PROJ library.

Add the QGIS repository:

sudo add-apt-repository ppa:ubuntugis/ppa sudo apt update
Install QGIS:

sudo apt install qgis qgis-plugin-grass

The PROJ library is now installed with QGIS.

Fedora:: sudo dnf install qgis qgis-grass

Further installation options¶

Linux: Debian/Ubuntu:

sudo apt-get install proj-bin

Fedora:

sudo dnf install proj

Red Hat:

sudo yum install proj
Mac OS X: Using Homebrew:

brew install proj

Or MacPorts:

sudo port install proj

Required Files for PROJ in LASTools¶

To ensure that the PROJ library functions correctly with LASTools, you need to have the following library files available:

proj
libcrypto
libcurl
libssl
sqlite3
tiff
zlib

Additionally, ensure that the PROJ data files, including the proj.db, are installed for full functionality.

File and Data Locations¶

file and data standart Directories: If LAStools uses the PROJ library, the files and data of the library are automatically searched for in the default standard directories of the installation via QGIS or OSGeo4W or Conda.
Custom Directory: Alternatively, you can place the library files and PROJ data in custom directories of your choice via environment variables. We recommend only using this option if the PROJ lib is not found automatically via the QGIS or OSGeo4W or Conda installations.

LASTOOLS_PROJ

for the PROJ library directory. If the PROJ library cannot find the PROJ data directory itself set

PROJ_LIB

Which is a PROJ-specific environment variable and specifies the directory to PROJ data.

To use these custom directories, set the environment variables via command line (cmd) as shown in the following example:

Windows: Temporary for the current session:

set LASTOOLS_PROJ=C:\path\to\proj_lib

and if required

set PROJ_LIB=C:\path\to\proj_data

Set environment variable permanently (applies to new CMD windows, but not to the current session):

setx LASTOOLS_PROJ “C:\path\to\proj_lib” and if required

setx PROJ_LIB “C:\path\to\proj_data”

Set environment variable permanently and system-wide for all users (need to run with admin rights):

setx LASTOOLS_PROJ “C:\path\to\proj_lib” /M

and if required

setx PROJ_LIB “C:\path\to\proj_data” /M
Linux: Temporary for the current session:

export LASTOOLS_PROJ=/path/to/proj_lib

and if required

export PROJ_LIB=/path/to/proj_data

Set environment variable permanently for this user: Open your Bash configuration file:

nano ~/.bashrc

Add this line at the end of the file:

export LASTOOLS_PROJ=/path/to/proj_lib

and if required

export PROJ_LIB=/path/to/proj_data

save and close the file and then execute the command

source ~/.bashrc

Set environment variable permanently and system-wide for all users: Open the system file for environment variables:

sudo nano /etc/environment

Add the variable to the file:

LASTOOLS_PROJ=”/path/to/proj_lib”

and if required

PROJ_LIB=”/path/to/proj_data”

save and close the file and then execute the command or (best) reboot your system to ensure the changes are affecting

source /etc/environment

Check the environment variables:

cmd - windows:

echo %LASTOOLS_PROJ% echo %PROJ_LIB%
linux:

echo $LASTOOLS_PROJ echo $PROJ_LIB

If you want to use the PROJ library later via QGIS, OSGeo4W or another installation, you must first delete the environment variables LASTOOLS_PROJ and PROJ_LIB if they have been set permanently.

Important Note¶

Ensure that the version of the PROJ data matches the version of the PROJ library to avoid compatibility issues. For more information and detailed instructions about the installation, refer to the official PROJ installation page https://proj.org/install.html

Licensing¶

This library is free to use. PROJ is released under the X/MIT open source License. For more information about the license and usage of the PROJ library, refer to the official PROJ repository or the official website https://proj.org.

Support¶

We invite you to join our LAStools Google Group (http://groups.google.com/group/lastools/). If you are looking for information about a specific tool, enter the tool name in the search function and you’ll find all discussions related to the respective tool.
Customer Support Page: https://rapidlasso.de/customer-support/.
Download LAStools: https://rapidlasso.de/downloads/.
Changelog: https://rapidlasso.de/changelog/.

If you want to send us feedback or have questions that are not answered in the resources above, please email to info@rapidlasso.de.