3706d88045
This commit adds the virtual method for running processing algs to the base c++ class, and adds the initial framework for c++ algorithm parameters. When running an algorithm, a QVariantMap is passed as the algorithm parameters. The high level API provided by QgsProcessingParameters should be used to retrieve strings/layers/doubles/etc from this QVariantMap. This allows advanced use cases, such as passing QgsProperty with the QVariantMap for "dynamic" parameters, where the value should be evaluated for every feature processed. E.g. if the buffer algorithm uses a dynamic property for distance, then the distance could be bound to either a field value or to a custom expression. This gets evaluated before buffering each feature to allow for advanced variable buffering. Support for dynamic parameters will be "opt in", and non default. So algorithms will need to specifically add support for dynamic properties as required.
About QGIS
QGIS is an Open Source Geographic Information System. The project was born in May of 2002 and was established as a project on SourceForge in June of the same year. We've worked hard to make GIS software (which is traditionally expensive commercial software) a viable prospect for anyone with basic access to a Personal Computer. QGIS currently runs on most Unix platforms (macOS/OS X included) and Windows. QGIS is developed using the Qt toolkit (http://qt.io) and C++. This means that QGIS feels snappy to use and has a pleasing, easy to use graphical user interface.
QGIS aims to be an easy to use GIS, providing common functions and features. The initial goal was to provide a GIS data viewer. QGIS has reached that point in its evolution and is being used by many for their daily GIS data viewing and editing needs. QGIS supports a number of raster and vector data formats, with new support easily added using the plugin architecture.
QGIS is released under the GNU Public License (GPL) Version 2 or above. Developing QGIS under this license means that you can (if you want to) inspect and modify the source code and guarantees that you, our happy user will always have access to a GIS program that is free of cost and can be freely modified.
Supported raster formats include:
- Grass
- USGS DEM
- ArcInfo binary grid
- ArcInfo ASCII grid
- ERDAS Imagine
- SDTS
- GeoTiff
- Tiff with world file
- WMS, WCS
Supported vector formats include:
- ESRI Shapefiles
- PostgreSQL/PostGIS
- GRASS
- GeoPackage
- Spatialite
- Other OGR supported formats
- MSSQL
- Oracle
- WFS
Note
Please follow the installation instructions carefully. After extracting the distribution, you can find the HTML version of the installation document in qgis/doc/index.html. The installation document is also available as PDF in the same directory.
Help us
Please submit bug reports using the QGIS bug tracker. When reporting a bug, either login or, if you don't have a qgis trac, provide an email address where we can request additional information.
Support
You can get support in the following ways:
- Using the QGIS community site at http://qgis.org
- Joining the qgis-users mailing list
- Using IRC by joining the #qgis channel on irc.freenode.net. Please wait around for a response to your question as many folks on the channel are doing other things and it may take a while for them to notice your question.
- Join the Gitter chat.
Contribute
QGIS is on GitHub at https://github.com/qgis/QGIS. If you wish to contribute patches you can fork the project, make your changes, commit to your repository, and then issue a pull request. The development team can then review your contribution and commit it upstream as appropriate. If you commit a new feature, add [FEATURE] to your commit message AND give a clear description of the new feature. A webhook will automatically create an issue on the QGIS-Documentation repo to tell people to write documentation about it.
If you are not a developer, there are many other possibilities which do not require programming skills to help QGIS to evolve. Check our project homepage for more information.