# Setting up a development environment

## Build requirements

The minimum requirements to build GDAL are:

- CMake >= 3.10, and an associated build system (make, ninja, Visual Studio, etc.)

- C99 compiler

- C++11 compiler

- PROJ >= 6.0

Additional requirements to run the GDAL test suite are:

- SWIG >= 4, for building bindings to other programming languages

- Python >= 3.6

- Python packages listed in autotest/requirements.txt

A number of optional libraries are also strongly recommended for most builds: SQLite3, expat, libcurl, zlib, libtiff, libgeotiff, libpng, libjpeg, etc. Consult Raster drivers and Vector drivers pages for information on dependencies of optional drivers.

## Vagrant

Vagrant is a tool that works with a virtualization product such as VirtualBox to create a reproducible development environment. GDAL includes a Vagrant configuration file that sets up an Ubuntu virtual machine with a comprehensive set of dependencies.

Once Vagrant has been installed and the GDAL source downloaded, the virtual machine can be set up by running the following from the source root directory:

    # VAGRANT_VM_CPU=number_of_cpus
    vagrant up

The source root directory is exposed inside the virtual machine at `/vagrant`, so changes made to GDAL source files on the host are seen inside the VM. To rebuild GDAL after changing source files, you can connect to the VM and re-run the build command:

    vagrant ssh
    cmake --build .

Note that the following directories on the host will be created (and can be removed if the Vagrant environment is no longer needed):

- `../apt-cache/ubuntu/jammy64`: contains a cache of Ubuntu packages of the VM, to allow faster VM reconstruction

- `build_vagrant`: CMake build directory

- `ccache_vagrant`: CCache directory

## Docker

The Linux environments used for building and testing GDAL on GitHub Actions are defined by Docker images that can be pulled to any machine for development. The Docker image used for each build is specified in linux_build.yml. As an example, the following commands can be run from the GDAL source root to build and test GDAL using the clang address sanitizer (ASAN) in the same environment that is used in GitHub Actions:

    docker run -it \
        -v $(pwd):/gdal:rw \
        ghcr.io/osgeo/gdal-deps:ubuntu_20.04-master
    cd /gdal
    mkdir build-asan
    cd build-asan
    ../.github/workflows/asan/build.sh
    ../.github/workflows/asan/test.sh

To avoid built objects being owned by root, it may be desirable to add `-u $(id -u):$(id -g) -v /etc/passwd:/etc/passwd` to the `docker run` command above.

## Building on Windows with Conda dependencies and Visual Studio

It is less appropriate for Debug builds of GDAL, than other methods, such as using vcpkg.

### Install git

Install git

### Install miniconda

Install miniconda

### Install GDAL dependencies

Start a Conda enabled console and assuming there is a c:\dev directory

    cd c:\dev
    conda create --name gdal
    conda activate gdal
    conda install --yes --quiet curl libiconv icu git python=3.7 swig numpy pytest zlib clcache
    conda install --yes --quiet -c conda-forge compilers
    conda install --yes --quiet -c conda-forge \
        cmake proj geos hdf4 hdf5 \
        libnetcdf openjpeg poppler libtiff libpng xerces-c expat libxml2 kealib json-c \
        cfitsio freexl geotiff jpeg libpq libspatialite libwebp-base pcre postgresql \
        sqlite tiledb zstd charls cryptopp cgal librttopo libkml openssl xz

Note

The `compilers` package will install `vs2017_win-64` (at time of writing) to set the appropriate environment for cmake to pick up. It is also possible to use the `vs2019_win-64` package if Visual Studio 2019 is to be used.

### Checkout GDAL sources

    cd c:\dev
    git clone https://github.com/OSGeo/gdal.git

### Build GDAL

From a Conda enabled console

    conda activate gdal
    cd c:\dev\gdal
    cmake -S . -B build -DCMAKE_PREFIX_PATH:FILEPATH="%CONDA_PREFIX%" \
                        -DCMAKE_C_COMPILER_LAUNCHER=clcache
                        -DCMAKE_CXX_COMPILER_LAUNCHER=clcache
    cmake --build build --config Release -j 8