QGIS Desktop is one of the most powerfull Open Software GIS software used in a daily basis. One of its key feature is the data processing module that allows users to process their data from various format and offers a rich set of functionalities, which guarantee a high degree of flexibility. This presentation will focus on this part of QGIS and will describe different way to process your data. It will show how to industrialize your process to be more productive in your daily use of QGIS. We will then describe the next key features of the module in QGIS 3.

1. Data Processing with QGIS 3

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About me
■ Name: Yves Jacolin
■ Company: Camptocamp (training and support)
■ Twitter: @yjacolin
■ Community:
○ GeoRezo.net moderator and administrator
○ OSGeo-Fr : funding member, president, contributor
○ OSGeo charter member
○ QGIS Documentation Leader

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Introduction
■ Data processing could help you for:
○ managing and processing your data
○ industrializing your process
■ Processing in QGIS is a light ETL

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Summary
■ Description of QGIS Processing Feature (in QGIS
2.x)
○ What it is
○ Data source
■ Geoalgorithms
■ Graphical modeler
■ Scripts
■ Tips & Tricks
■ What’s new: QGIS 3.0 and beyond

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Short description

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What is Processing in QGIS?
■ Python plugin for data processing
○ Created by Victor Olaya
○ A lot of new feature and improvment since its creation
■ Several providers
○ GDAL-OGR
○ SAGA
○ Orfeo Tools Box
○ GRASS
○ R-Script
○ TauDEM
○ LAStools

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What is Processing in QGIS?
■ Panels and windows:
○ Options
○ Toolbox
○ Graphical modeler
○ Results viewer
○ Commander

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Overall Processing features and
configuration

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Configuration
■ Path to providers
■ Activate features
■ Default styling configuration
for layers
■ Default extension

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Data source
■ Read and write all data source from QGIS
■ Internal temporary data source: shapefile
○ Break field name to 10 characters
○ ...

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Geoalgorithms

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Finding geoalgorithms
■ By providers:
○ GRASS
○ SAGA
○ GDAL/OGR
■ More from plugin
○ QuickOSM
■ Scripts repository

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Run an algorithm
■ Refactoring fields algorithm

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Graphical modeler
■ Build your own custom models from existing algorithms

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Graphical Modeler
■ Link algorithms each others for a full process

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Graphical modeler
■ Several data inputs
○ Raster and vector layers
○ Attribut table
○ Boolean, Strings, Number
○ File, extent
■ All modules are available in the
graphical modeler

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Graphical modeler
■ Run your algorithm!

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Graphical modeler
■ Contextual menu for field:
○ Vector/raster layers: Open an external file
○ Number/string: use of an expression
○ Resulting field: export to a temporary file, a file or use
expression
■ Iterating on features

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Scripts
■ Do you feels limited by the graphical modeler?

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Custom scripts
■ All same features than before
■ QGIS Python API
■ Just a simple script

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Custom scripts
■ Iterating
■ Specific action on field
○ Expression
○ Export to a tmp file
○ Batch
○ Log management
○ Help

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I want more!
■ Tips and tricks
■ The futur!

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Tips & Tricks
■ Use your scripts and custom algorithms in another
algorithm
■ Export scripts
■ Create a menu in QGIS maint interface from models
■ Batch processing

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Tips & Tricks
■ Download new scripts from public or private git
repository

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The futur!
■ Some limitations:
○ Temporary files (shp) when two processes are linked each other
○ Python scripts
○ Performance issue with lot of data
■ On-going works :
○ Big refactoring by Nyall Dawson
- Multi-threading (done)
- No temporary file between each processes
- Python to C++ (on going)
- Models break (on going)
- Removing duplicate algorithms

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UI Refreshing

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Move Processing options to QGIS settings

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Huge thanks to all contributors!

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Thanks!
■ Twitter: @yjacolin
■ Email: yves.jacolin@camptocamp.com