MDAL

Mesh Data Abstraction Library

MDAL is an OSGeo Community Project

• see Unstructured Mesh Layers
• see 3D layered meshes
• see 1D meshes
• see Mesh frame editing

Mailing List

To discuss development and usage, please use mdal-developer@lists.osgeo.org

Supported Formats

You can use MDAL to load the following file formats:

• 2DM: Mesh representation of various various hydrodynamic modelling packages (e.g. BASEMENT, TUFLOW)
• XMS TIN: Mesh TIN representation in ASCII format
• NetCDF: Generic format for scientific data. Examples can be found here
• GRIB: Format commonly used in meteorology. Examples can be found here
• XMDF*: Outputs of various hydrodynamic modelling packages (e.g. TUFLOW, HYDRO_AS-2D)
• XDMF*: As an example, hydraulic outputs from BASEMENT 3.x modelling package
• DAT: Outputs of various hydrodynamic modelling packages (e.g. BASEMENT, HYDRO_AS-2D, TUFLOW)
• 3Di*: 3Di modelling package format based on CF Conventions
• UGRID*: Unstructured Grid format based on CF Conventions
• FLO-2D: Outputs of the FLO-2D modelling package
• Selafin/Serafin: Outputs of the TELEMAC 2D hydrodynamic modelling package
• HEC-RAS: Outputs of the HEC-RAS modelling package
• SWW: Outputs of the ANUGA modelling package
• Esri TIN: Format for storing elevation data as a triangulated irregular network
• SAGA FLOW**: Rasters in the SAGA flow direction format
• ADCIRC***: ADCIRC hydrodynamic model results
• PLY: Stanford Polygon Format also useful for mesh created from point clouds by PDAL
• DFSU*:DHI Flexible File Format (External Driver)
• DFS2*:DHI Grid Series File (External Driver)
• H2i*: Outputs of the H2i modelling package
• MIKE 21: Mesh Text/plain file with *.mesh extension

* Data lazy loaded

** Formats can be preprocessed using QGIS Crayfish Mesh processing algorithm to one of supported formats

*** Results should pre pre-processed to become UGRID compliant

Format	Mesh Frame Support	Mesh Lazy Loaded	1D Data Support	2D Data Support	3D Data Support	Data Lazy Loaded
2DM	READ-WRITE	N/A	N/A	N/A	N/A	N/A
XMS TIN	READ-ONLY	N/A	N/A	N/A	N/A	N/A
Esri TIN	READ-ONLY	N/A	N/A	N/A	N/A	N/A
GDAL-NetCDF	READ-ONLY	NO	NO	READ-ONLY	N/A	NO
GDAL-GRIB	READ-ONLY	NO	NO	READ-ONLY	N/A	NO
XMDF	N/A	N/A	NO	READ-ONLY	READ-ONLY	YES
XDMF	N/A	N/A	NO	READ-ONLY	NO	YES
DAT	N/A	N/A	READ-ONLY	READ-WRITE	N/A	NO
3Di	READ-ONLY	NO	READ-ONLY	READ-ONLY	NO	NO
UGRID	READ-WRITE	NO	READ-ONLY	READ-WRITE	NO	NO
FLO-2D	READ-ONLY	NO	READ-ONLY	READ-WRITE	NO	NO
Selafin	READ-WRITE	NO	NO	READ-WRITE	NO	NO
SWW	READ-ONLY	NO	NO	READ-ONLY	NO	NO
PLY	READ-WRITE	N/A	READ-WRITE	READ-WRITE	READ-WRITE	N/A
DFSU	READ-ONLY	N/A	NO	READ-ONLY	READ-ONLY	YES
DFS2	READ-ONLY	N/A	NO	READ-ONLY	N/A	YES
H2i	READ-ONLY	NO	NO	READ-ONLY	N/A	YES
Mike21	READ-WRITE	N/A	N/A	N/A	N/A	N/A

Standalone Installation

MDAL can be installed as a stand-alone package (i.e. outside of QGIS) using conda.

The package can installed by running :

conda install -c conda-forge mdal

This package provides the MDAL ABI through the mdal shared object( i.e. mdal.dll, libmdal.dylib or libmdal.so) and the mdalinfo CLI.

A friendly note about versions. The conda package is usually targetted at the latest version of GDAL on conda-forge. This is usually a later version than used by QGIS. Therefore, there may be some subtle differences in behaviour when loading e.g. GRIB files.

Versioning and integration in QGIS

QGIS contains internal copy of MDAL library in following versions:

QGIS	MDAL	Features
3.0.2	N/A	2D meshes
3.2.3	0.0.3
3.4.14	0.0.10
3.6.3	0.3.2	Many new formats supported
3.8.3	0.3.3
3.10.0	0.3.3
3.10.1	0.4.0	Save datasets for some formats
3.10.2	0.4.1
3.10.3	0.4.2
3.12.0	0.5.1	3D layered meshes
3.14.0	0.6.1	1D meshes
3.16.0	0.7.1	Mesh creation, PLY format
3.18.0	0.8.0	Dynamic drivers, DFSU format
3.20.0	0.8.1
3.22.0	0.9.x	DFS2, DFSU 3D, PLY write
3.24.0	1.0.x	TBD
3.24.1	0.9.90	H2i format
3.28.0	1.0.0	write dataset capability for UGRID format
3.28.2	1.0.1
3.28.4	1.0.2
3.30.0	1.0.2
3.36.0	1.1.0	Mike21 format support read/write
3.38.0	1.2.0	Groundwater / surface water meshes for 3Di format

versions X.Y.9Z are development versions or alpha/beta releases (e.g. 0.4.90, 0.4.91, ...)

Backporting

We maintain the version of MDAL used in current QGIS LTR version. For any CRITICAL bugfixes (e.g. crashes, coredumps, regressions, data corruption) we want to backport the code to MDAL LTR version. To do this, label your pull request with label "backport release-XXX". Once pull request is merged, mdal-bot will automatically create a pull request to specified branch. Note that the pull request must be squashed to 1 commit for automatic backport.

Development

Coding standards & Contribution

MDAL is an open-source project and all contributions to either documentation, format support, testing or code are more than appreciated. Any change to the code must go through Pull Request, followed by review by one of the MDAL core developers.

To be able to accept a pull request, please verify that:

• code follows QGIS coding style
• code is properly unit-tested with a set of small test files under tests/data/<format> (code coverage > 90%)
• code is reasonably documented and easy to read
• code compiles without any compilation warnings
• no dead-code (e.g. unused functions) or commented out code
• all new code or new dependencies (e.g. libraries) have GPLv2 compatible license
• all tests pass
• the code if properly formated (run ./scripts/check_all.bash)

Please respect our Contributor Covenant Code of Conduct

Build

Windows

For 64-bit version:

• Install Microsoft Visual Studio 16 2019
• Install OSGeo4W (64bit) to C:\OSGeo4W64
• Run "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\Common7\Tools\VsDevCmd.bat -arch=x86" to initialize Visual Studio environment (or open VS terminal). For community version, run similar command "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\Tools\VsDevCmd.bat -arch=x86"
• Create build directory mkdir build;cd build
• Run (to get a Release build)

cmake -G "Visual Studio 16 2019" -DCMAKE_BUILD_TYPE=Rel  ^
    -DENABLE_TESTS=ON ^
    -DNETCDF_PREFIX="C:\OSGeo4W64" ^
    -DHDF5_ROOT="C:\OSGeo4W64" ^
    -DGDAL_DIR="C:\OSGeo4W64" ^
    -DGDAL_LIBRARY="C:\OSGeo4W64\lib\gdal_i.lib" ^
    -DGDAL_INCLUDE_DIR="C:\OSGeo4W64\include" ^
    -DLIBXML2_LIBRARIES="C:\OSGeo4W64\lib\libxml2.lib ^
    -DLIBXML2_INCLUDE_DIR="C:\OSGeo4W64\include\libxml2" ^
    -D EXTERNAL_DRIVER_DHI_DFS=OFF ^
    ..

• Build the executables cmake --build . --config Release
• Adjust the PATH (or copy the mdal.dll to folder test\Release) with command set PATH="C:\OSGeo4W64\bin;<your_build_dir>\build\tool\Release\;<your_build_dir>\build\mdal\Release;%PATH%"
• Run the tests ctest -VV -C Release --exclude-regex mdal_dynamic**

Linux

install dependencies for drivers

sudo apt-get install libgdal-dev libhdf5-dev libnetcdf-dev libxml2-dev

and use cmake to generate build system

mkdir build;cd build
cmake -DCMAKE_BUILD_TYPE=Rel -DENABLE_TESTS=ON ..
make

MacOS

First you need to install qgis-deps dependencies,

To build, create build system with cmake and make sure you use dependencies from qgis-deps and not system ones

mkdir build;cd build
cmake -DCMAKE_PREFIX_PATH=/opt/QGIS/qgis-deps-0.5.3/stage -DCMAKE_BUILD_TYPE=Debug -GNinja -DENABLE_TESTS=ON ../
ninja

External Drivers

see DFSU

Tests

run ctest command in build directory ctest -VV

Code syntax

format code:

cd scripts
./check_all.bash

or use git pre-commit hook

cd MDAL
ln -s ./scripts/mdal_astyle.bash .git/hooks/pre-commit

Windows

On Windows, the code can be formatted using the following :

cd MDAL
powershell -ExecutionPolicy BYPASS scripts\check_all.ps1