In the commit 15199 Tim Sutton added tips shown on QGIS startup. Those tips can be enabled/disabled the QGIS settings.
So far, the number of tips is very small - about a dozen. Anyone who wants to can submit their tips for inclusion. The requirements are simple:
the tip should have a concise title
brevity is the soul of wit. The content of the tip should not exceed one or two paragraphs
only basic HTML primitives are allowed: links, lists, etc. The full list of supported tags can be found here
the tip should be useful to as many users as possible, or describe functionality that is not obvious
A bit earlier, in commit 15195, a separate window was added with a list of organisations that supported (and support) the project financially, i.e. sponsors.
QGIS is not only a ready-to-use desktop GIS, but also a set of libraries that can be used to create custom GIS applications. Unfortunately, when creating such applications, developers have to implement some GUI elements from scratch. An example of such a widget is the list of loaded layers (sometimes incorrectly called a legend).
In this post I will show the process of embedding a layer list widget into a PyQGIS application. The widget was developed by Germán Carrillo and you can get the code and read how to use it in German’s post “Layer list widget for PyQGIS applications” on the GeoTux blog.
A guy called Alsi Yilmaz has analysed the usability of QGIS. I read it diagonally, there are some remarks that make sense, but the rest… is nonsense.
On the other hand, Marco Hugentobler made a lot of people happy: the experimental support for joined tables (I wrote about this earlier) was moved to trunk by commit 15155.
I also can’t get around to finishing a little “secret project” and publish the results.
The so-called “new symbology” in QGIS has an impressive set of features and allows users to create their own symbols from the simplest to the most complex. Unfortunately, it does not provide a mechanism for sharing symbols, and it is not possible to use multiple symbol libraries at the same time.
I decided to fix at least some of the shortcomings and prepared a patch that allows the import/export of symbols. This is the third patch of this kind among my fixes, the previous two were also import/export related (one for import/export of PostGIS and WMS connection settings, and the other for import/export of custom keyboard shortcuts).
Despite the fact that QGIS now has a built-in raster calculator (I wrote about this a couple of times), the RasterCalc plugin I developed is still quite popular. I don’t know how to explain it: either it’s a matter of habit, or my calculator is more convenient… I’d like to know what the reason is, maybe I should make a poll.
Why this preface? For a long time, I’ve been “terrorised” by requests to add support for conditional operators to my plugin. A guy from Spain was particularly active. And no matter how often I pointed out that I was busy with other projects, no matter how hard I tried to avoid it, nothing helped. After a short break, the “attacks” were repeated. Apparently, they had decided to wear me down.
The inclusion of a patch that added comparison operators (submitted by Ghislain Picard) didn’t help either. It was not enough, and it was not what they were looking for. People wanted more, something similar to r.mapcalc from GRASS and preferably with the same syntax.
Well… I have to admit, they got it. Today this most wanted feature is implemented. However, the syntax is different from r.Mapcalc’s, because I didn’t want to make the already complex parsing code even more complicated. Now you can do things like:
compare pixel values with a constant and replace pixel values that meet the condition with another value
compare pixel values with corresponding pixels of another raster/band, and replace pixel values that match the condition with corresponding values from the third raster/band
other similar things
This nice feature is still in my local repository. I will not commit it to the public repository until the documentation has been updated. And I really don’t have the mood or energy to do that. I don’t like writing, whether it’s an essay, an article, or anything else. There are times when it is easy to write, but those are rare.
There is another reason or two, to be precise and honest. Firstly, I’m thinking about optimising the plugin a bit: operations on large rasters use a lot of CPU and memory. And secondly, that very active Spaniard made another feature request the other day, and I have a feeling that he will be as persistent in his efforts to get me to implement it as he was before.
But I haven’t made a final decision yet. Maybe the conditional operator should be enough for a new version and I should not bother with refactoring and optimisation? Or should I wait a bit, but release an even more powerful calculator and consolidate the success of the first versions?
Alessandro Furieri has announced the SpatiaLite Cookbook, an excellent guide to SpatiaLite with many practical examples, optimisation tips and information on using SpatiaLite with different programming languages. You can check it out here.
Frank Warmerdam has announced that OSGeo4W is moving to the recently released GDAL 1.8.0. Instead of GDAL 1.5.4, the default version will be 1.8.0, additional packages like gdal-python, gdal-autotest, gdal-ecw etc. will also be updated or removed if no longer needed.
For compatibility with some packages that still require GDAL 1.5.4, a new package gdal15dll (with the necessary libraries) will be added. This package will be automatically installed if needed.
Since the transition to a new version of GDAL is a rather laborious and time-consuming process, the update of some packages included in OSGeo4W is temporarily suspended. In particular, this affects QGIS nightly builds.
The maintainers of the QGIS OSGeo4W package have already announced that they will rebuild the package with GDAL 1.8.0 as soon as possible, GRASS will be rebuilt after GRASS 6.4.1 is released.
Frank Warmerdam announced the release of GDAL 1.8.0.
GDAL is a free translation library for raster and vector geospatial formats. The library provides applications with a single generic data model for all supported formats. In addition to the library itself, GDAL includes a set of powerful command line utilities for data translation and processing.
The list of changes is impressive, and the adoption of RFC 29 and RFC 30 is particularly pleasing. For example, the changes described in RFC 29 will significantly improve performance and reduce memory consumption when processing vector data (about 1.5-2.5 times, according to tests). So far, SetIgnored is only implemented for shapefiles (by Martin) and SpatiaLite (my patch).
Once threading_branch is merged into trunk, QGIS will open large shapefiles much faster and many geoprocessing scripts will speed up. By the way, I will have to rewrite my data extraction script to take advantage of these changes.
I am looking forward to adding GDAL 1.8.0 to OSGeo4W, especially as Frank promised a global update of OSGeo4W after the release. GDAL 1.8.0 will be the main version instead of the outdated 1.5.4, and Python 2.5 will be replaced by 2.7.
I have created an OSGeo4W-compatible QGIS package from the raster-providers branch (r15015) and uploaded it to the forum. As the name suggests, developers in this branch are working on optimising raster providers; in particular, one of the results will be support for on-the-fly raster reprojection (already available for the GDAL provider).
QGIS has been built with GRASS and Python support and uses GDAL 1.7.3 (all dependencies are from OSGeo4W). To use it:
install QGIS and all its dependencies using the OSGeo4W installer
download the package from the forum thread
extract the contents of the package to the OSGeo4W root directory (by default this is C:\OSGeo4W)
