The 9th QGIS developer meeting in Valmiera (Latvia) has come to an end.
Since the QGIS code is already frozen (with some caveats), almost all of the commits were aimed at fixing bugs, improving stability, and shaping the new API.
It’s a thankless task to list everyone by name, there are no idlers at hackfests. I’ll just go through the things that interest me personally (and that affect me to a greater or lesser extent):
Radim continued to improve the raster subsystem (in particular, he fixed a number of problems with the handling of NODATA values)
Jürgen, as always, fixed bug after bug, and also worked on support for different encodings (yes, yes, Frank’s commit to GDAL will have long-lasting consequences)
Borys worked on the new plugin installer
Victor and I worked on SEXTANTE: fixing bugs, writing new tests, updating documentation and help files
Werner, Paolo, Otto, Larissa, Raymond worked on the user manual, cleaning up the wiki and migrating the website
In addition, all hackfest participants were very active in discussing a range of issues:
implementation of GRASS raster algorithms
the documentation creation and translation process
SEXTANTE’s new features and architecture
PSC structure and role
new plugin installer
new website
and other issues
The next developer meeting is scheduled for September (earlier than usual) and will be held in Brighton, UK.
I have finished translating the QGIS 1.8.0 User Guide into Russian. Online and PDF versions should be available tomorrow via links on the official website.
Another of my modest contributions to QGIS is now in the master. I added 4 new tools to customise raster rendering: brightness and contrast controls (raster pipes, once you understand how they work, are cool and flexible thing). In addition to changing the raster rendering on the fly, users can also save the modified image for future use.
TauDEM (Terrain Analysis Using Digital Elevation Models) is a set of Digital Elevation Model (DEM) tools for extracting and analysing hydrological information from the topography represented by a DEM. It was developed at Utah State University (USU) for hydrological analysis of digital elevation models and watershed delineation.
TauDEM has recently been integrated into QGIS as a SEXTANTE provider. This makes it possible to run TauDEM tools directly from QGIS, easily perform complex analysis workflows, and view the generated results.
In this post, I will show how to perform some hydrological analysis tasks in QGIS using TauDEM, namely how to delineate watersheds and extract stream networks.
About a week ago, Alessandro Furieri announced the release of SpatiaLite 4.0.0 — a spatial extension to SQLite. There are not just a lot of changes, there are VERY many of them. And some of them may cause compatibility problems, so all users should read the migration guide.
Among the most interesting features:
tessellation support
VirtualOGR driver
support for SQL/MM topology
and more
And yesterday, the SpatiaLite data provider in QGIS was updated. Compatibility with databases created in previous versions of SpatiaLite is maintained. However, you will need to convert your databases to the SpatiaLite 4.0.0 format (you can use spatialite_convert from spatialite-tools) to take full advantage of the new features.
SEXTANTE is a powerful and flexible platform for performing geospatial analysis in QGIS. It provides access to its own geoprocessing functions as well as algorithms implemented in third-party applications, making analysis easier and more productive.
Initially written in Java and only available to gvSIG users, SEXTANTE has gradually extended its presence to other GIS. In 2012, a Python version was developed for use with QGIS. It immediately attracted a lot of interest from users and developers alike, and in September 2012 SEXTANTE was integrated into QGIS as a core plugin.
SEXTANTE in QGIS allows you to use the main features of well-known third-party GIS tools (SAGA GIS, GRASS GIS, TauDEM, OrfeoToolBox…) and algorithms implemented directly in SEXTANTE (fTools, MMQGISX…) via a unified interface.
It also offers a wide range of possibilities for automating data processing: combining repetitive steps of applying algorithms to data in a custom analysis model, writing and using Python scripts, batch processing mode. Advanced users can further increase their productivity by using SEXTANTE algorithms and the Python console together.
Two of my plugins are in the TOP-20 by downloads, 4 by ratings and 5 by votes. It’s a small thing, but it’s nice.
My plugins
Actually, the list is not complete, as there are still C++ plugins that are distributed as source code and plugins that are not published in the official repository. And some plugins, although they have been significantly reworked by me and are now maintained by me, were originally created by others.
As I wrote before, Oslandia kept their promise, and during the 8th QGIS developer meeting, the Atlas plugin was integrated into the QGIS print composer. This has been made possible thanks to the financial support (although not the full amount has been raised) of the following individuals and organisations:
Agence de l’eau Adour-Garonne
City of Uster, Switzerland
Spencer Gardner
Giovanni Allegri
John C. Tull
Bill Williamson
Ujaval Gandhi
The workflow remains the same: create a print layout and specify a coverage layer that will be used to generate the atlas. In addition, it is now possible to create complex labels using the full power of QgsExpression and the attributes of the coverage layer.
Let’s go through the process of making an atlas step by step.
QGIS plugin developers should note that it was decided at the hackfest to make changes to the plugin metadata. Namely:
added mandatory author field
added mandatory email field
the authorName field is declared deprecated and is ignored when parsing metadata
The new fields must be present in both the __init__.py file and the metadata.txt file. The purpose of this change is to separate the actual author of the plugin from the plugin maintainer. For plugins already uploaded to the repository, these metadata fields will be filled in automatically using information from LDAP, but for all new plugins, these fields should be set by the developer.
Attempts to import SEXTANTE from its SVN repository into the QGIS repository on GitHub with the history intact are a thing of the past. Also in the past were numerous fixes for bugs that appeared after the import, writing build rules, and fixing issues caused by the directory structure change. SEXTANTE is now officially included in QGIS as a core plugin.
Thanks to Victor, Tim, Camilo. Well, and me too :-).
