A long time ago, in a galaxy far, far away… Almost a year ago, I was involved in a project that is now almost dead. It was notable not only for its ideas, but also for the fact that its main development tool was Delphi. In my opinion, this was not the best choice: if you need ObjectPascal so much, you should use FreePascal, which supports 64-bit and is cross-platform, open, and free. But that’s not the point.
The GDAL library was supposed to be used to work with vector and raster data, but… As it turned out, there are no bindings for Pascal. There are bindings for Python, R, Perl, PHP and a few others, but not for Pascal. Well, there is a ticket in trac from 4 years ago, but the solution proposed there is basically a hack, because it requires changes in the GDAL code and a custom GDAL build. We had to do something… So I remembered my youth, remembered how I used to code in Pascal and tried to make a wrapper for the library.
I tried to keep the code compatible with both FreePascal and Delphi. Unfortunately, for various reasons, I did not manage to create a complete wrapper. Maybe when I have the time and resources, I will slowly add the missing bits. In the meantime, I have decided to publish the current implementation on GitHub. I hope someone will find it useful.
Following the news of the successful cross-compilation of QGIS on Android, QGIS was launched on the ASUS Transformer tablet (Android 3.2) and the Samsung Galaxy phone (CyanogenMod 7RC1).
At the moment, QGIS runs without some features (e.g., no Python support, not all providers are available, etc.), but the GUI is fully functional, although there are some problems using it on mobile phones due to the small screen size.
If you want to give it a try, there is a pre-built APK (note that you need to install Ministro and Qt first; the total download size is ~130 MB). There is also a compilation guide on the wiki.
Video of installing and running QGIS on ASUS tablet
I can’t stop being pleased with the popularity of RasterCalc. It is a very useful and, above all, functional tool. Today, the calculator has two new functions (the initial patch was provided by Ludovic Mercier): composeRgb and extract.
The composeRgb function creates a 3-band raster from individual channels. Example of use:
The output will be a 3-band raster: band 1 of the clearcuts raster will be used as the first output band, band 5 of the clearcuts raster will be used as the second output band, and the third output band will be the average of bands 5 and 6 of the clearcuts raster.
The extract function extracts a subset of bands from a multiband raster and saves it as another raster. Example of use (assuming the Clearcuts raster has 10 bands):
extract([clearcuts]@1, 3, [5,7], 10)
The output will be a multi-band raster consisting of channels 3, 10 and all channels from the interval [5, 7]. I.e. the output image will have 5 bands (bands 3, 5, 6, 7 and 10 of the input raster).
The implementation (even with my changes) is far from optimal, but I don’t have time for proper refactoring and optimisation. Maybe I will rewrite it completely later.
Marco Bernasocchi, who is working on porting QGIS to Android at GSoC 2011, reports on a successful cross-compilation of QGIS using the Android NDK r5c.
This was preceded by work on porting all the libraries needed to build QGIS (GDAL, GEOS, Proj, etc). Porting SpatiaLite and optimising the interface for tablets are next on the list.
It is no secret that one of the most common raster formats, TIFF, is able to store georeferencing information within the file, turning it into a GeoTIFF. Everything would be fine if it weren’t for one nuance: the vast majority of graphic editors suffer from “star fever”, believing that unrecognised tags have no place in the file and happily removing this valuable information when saving the file.
This feature of graphic editors is often used to “reset” georeferencing (for example, if the image is incorrectly georeferenced and needs to be georeferenced from scratch). A natural question arises: what to do if you need to edit the image in a graphics editor but do not want to lose the georeferencing? The answer is not original, it is necessary to save it in an external file (the so-called world file).
Marco Hugentobler has added a new marker type called “Ellipse” to QGIS. It looks like this
Point layer renderer using Ellipse marker
You can use this type of marker to create not only ellipses but also other shapes such as rectangles, triangles or crosses. Both the height and width of the marker can be changed; all basic parameters (fill colour, outline colour and thickness, rotation) are available, and most properties can be data-defined.
In the future, the Ellipse marker will be merged with the Simple marker.
QGIS Browser is now not only available as a standalone application but also integrated into QGIS. Martin has added a dockable Browser panel showing a directory tree and registered WMS connections. Double-clicking on a layer in the Browser panel adds it to QGIS.
And Pirmin Calberer has managed to get his Globe plugin into the QGIS core. More information about the plugin can be found here.
The initiative by kCube Consulting that they started last December failed miserably. The idea was that a full-time developer from this company would work on QGIS for half a year, and after discussion, the main focus of the work was determined — bug fixing. This may not be very interesting, but it is certainly useful.
Six months have passed… Nobody has seen the promised monthly reports. A search of the bugtracker reveals only 6 (six!) issues where our hero has “done” anything. Of these 6 bugs, only 2 (two, really?!) are actually closed, and one patch has been almost completely reworked by one of the core developers.
There is nothing to add other than the words from the post title.
