OSGeo Statement: EU Cyber Resilience Act

QGIS Planet

FOSSGIS 2014 slides

Neues in QGIS 2.2 Nach dem lange erwarteten Release von QGIS 2.0 im September 2013, sind ab diesem Jahr neue Versionen im Viermonatszyklus geplant. Es werden die neuen Funktionen in QGIS 2.2, wie z.B. DB-Relationen mit verschachtelten Formularen, die erweiterten Methoden zur Transformierung geographischer Koordinatensysteme, zahlreiche Verbesserungen im Print Composer und ein komplett überarbeiteter DXF Export vorgestellt. Zusätzlich wird eine Vorschau auf das multithreaded Rendering gegeben und die neuen Mitglieder im Project Steering Committee vorgestellt
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The PyQGIS Programmer's Guide

The PyQGIS Programmer’s Guide is now available in both paperback and PDF. A sample chapter is also available for download. The book is fully compatible with the QGIS 2.x series of releases. See locatepress.com for details.
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Build and deploy c++ QGIS custom application on windows

After a lot of troubles, I managed to compile and deploy a QGIS c++ app on windows. This small guide will describe the steps I followed. This has been tested on win xp and windows 7, both in 32 bits.

Development environment

Your app must be built using MSVC 9.0 (2008) since QGIS in OSGeo’s package was built with it. Hence, MinGW cannot be used.

  1. Install Microsoft Visual Studio Express 2008.
  2. Install QGIS and Qt libs using OSGeo4W installer
  3. Install Qt Creator
  4. If you want a debugger,you should install CDB. This can be achieved by installing Windows SDK environment. In the installation process, only select Debugging toos for windows.

I wasn’t able to use the compiler yet, so I am not 100% sure about 4.

Now, if you want to build using Qt Creator, it must be started in a proper environment. Adapt this batch to launch Qt Creator:

ECHO Setting up QGIS DEV ENV

set PYTHONPATH=

set OSGEO4W_ROOT=C:\OSGeo4W
call "%OSGEO4W_ROOT%\bin\o4w_env.bat"

@set QMAKESPEC=win32-msvc2008
@set PATH=%OSGEO4W_ROOT%\bin;%OSGEO4W_ROOT%\apps\qgis-dev\bin;%PATH%

@set INCLUDE=%INCLUDE%;%OSGEO4W_ROOT%\include;%OSGEO4W_ROOT%\apps\qgis-dev\include
@set LIB=%LIB%;%OSGEO4W_ROOT%\lib;%OSGEO4W_ROOT%\apps\qgis-dev\lib

path %OSGEO4W_ROOT%\bin;%SYSTEMROOT%\System32;%SYSTEMROOT%;%SYSTEMROOT%\System32\wbem;C:\Progra~1\Git\bin;C:\Qt\qtcreator-3.0.1\bin;%PATH%

set VS90COMNTOOLS=C:\Program Files\Microsoft Visual Studio 9.0\Common7\Tools\
call "C:\Program Files\Microsoft Visual Studio 9.0\VC\vcvarsall.bat" x86

start "Qt Creator" /B C:\Qt\qtcreator-3.0.1\bin\qtcreator.exe %*

Then, you need to configure a proper kit in Qt Creator.

  1. Go to Options -> Build & Run -> Compilers and check that Microsoft Visual C++ Compiler 9.0 is correctly detected.
  2. Then in Qt Versions tab, add Qt from the OSGeO installation, normally c:\OSGeo4W\bin\qmake.exe
  3. In Debuggers tab, add cdb.exe found in c:\Debugging tools for windows\ 
  4. Finally, check in Kits that it is properly configured.

Building the application

This is what looks like an application project file.

QT += core gui xml
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = hfp
TEMPLATE = app
SOURCES += YOURSOURCES
HEADERS +=YOUR HEADERS
FORMS += YOUR FORMS
RESOURCES += images/images.qrc

win32:CONFIG(Release, Debug|Release) {
 LIBS += -L"C:/OSGeo4W/lib/" -lQtCore4
 LIBS += -L"C:/OSGeo4W/lib/" -lQtGui4
 LIBS += -L"C:/OSGeo4W/lib/" -lQtXml4
 LIBS += -L"C:/OSGeo4W/apps/qgis-dev/lib/" -lqgis_core
 LIBS += -L"C:/OSGeo4W/apps/qgis-dev/lib/" -lqgis_gui
}
else:win32:CONFIG(Debug, Debug|Release) {
 PRE_TARGETDEPS += C:/OSGeo4W/lib/QtCored4.lib
 PRE_TARGETDEPS += C:/OSGeo4W/lib/QtGuid4.lib
 PRE_TARGETDEPS += C:/OSGeo4W/lib/QtXmld4.lib
 LIBS += -L"C:/OSGeo4W/lib/" -lQtCored4
 LIBS += -L"C:/OSGeo4W/lib/" -lQtGuid4
 LIBS += -L"C:/OSGeo4W/lib/" -lQtXmld4
 LIBS += -L"C:/OSGeo4W/apps/qgis-dev/lib/" -lqgis_core
 LIBS += -L"C:/OSGeo4W/apps/qgis-dev/lib/" -lqgis_gui
}
win32:{
 INCLUDEPATH += C:/OSGeo4W/include
 DEPENDPATH += C:/OSGeo4W/include
 INCLUDEPATH += C:/OSGeo4W/apps/qgis-dev/include
 DEPENDPATH += C:/OSGeo4W/apps/qgis-dev/include
 DEFINES += GUI_EXPORT=__declspec(dllimport) CORE_EXPORT=__declspec(dllimport)
}
unix {
 LIBS += -L/usr/local/lib/ -lqgis_core -lqgis_gui
 LIBS += -L/usr/local/lib/qgis/plugins/ -lgdalprovider
 INCLUDEPATH += /usr/local/include/qgis
 DEFINES += GUI_EXPORT= CORE_EXPORT=
}

Remarks

  • GUI_EXPORT and CORE_EXPORT must be set to __declspec(dllimport). I don’t know exactly what it means, but I found out reading this thread, with some hazardous tries. If you don’t set these, you won’t be able to call any variable defined as extern in QGIS (e.g. cursors).
  • Qt release libraries shall not be mixed up with debug config in your project. In other words, use release libs for release mode and debug libs for debug mode.

With this, you should be able to compile your QGIS application in Qt Creator!

You can find some coding examples on github which are a bit old but still useful to start.

Now, to get the whole potential of QGIS libs, you must initialize the QgsApplication in your main window class:

#if defined(Q_WS_WIN)
  QString pluginPath = "c:\\OSGeo4W\\apps\\qgis-dev\\plugins";
  QString prefixPath = "c:\\OSGeo4W\\apps\\qgis-dev\\";
#else
  QString pluginPath = "/usr/local/lib/qgis/plugins/";
  QString prefixPath = "/usr/local";
#endif

  QgsApplication::setPluginPath( pluginPath );
  QgsApplication::setPrefixPath( prefixPath, true);
  QgsApplication::initQgis();

Deploying on windows

Since QGIS is not to be installed on the target computer, the built app will not be able to find the path declared in previous code.
There is probably a better approach, but here is a way to solve this:
Change the path to

  QString pluginPath = "c:\\myapp\\qgis\plugins";
  QString prefixPath = "c:\\myapp\\qgis";

This means you must deploy the app to this exact location: c:\myapp. In this directory, you need to create a qgis folder in which you will copy c:\OSGeo4W\apps\qgis-dev\resources and c:\OSGeo4W\apps\qgis-dev\plugins.

Besides, this you will need to copy some DLLs to be able to run the applications. You might want to use the dependency walker to find which are needed.

The batch file hereafter creates a folder on the building machine that will contain all the needed files in my case (it might be different in your case).

rmdir c:\myapp /Q /S
mkdir c:\myapp
mkdir c:\myapp\iconengines
mkdir c:\myapp\qgis
mkdir c:\myapp\qgis\resources
mkdir c:\myapp\qgis\plugins

copy PATHTOMYAPP\build-myapp-Desktop-Release\release\myapp.exe c:\myapp\
copy c:\OSGeo4W\bin\QtCore4.dll c:\myapp\
copy c:\OSGeo4W\bin\QtGui4.dll c:\myapp\
copy c:\OSGeo4W\bin\QtXml4.dll c:\myapp\
copy c:\OSGeo4W\bin\QtNetwork4.dll c:\myapp\
copy c:\OSGeo4W\bin\QtSvg4.dll c:\myapp\
copy c:\OSGeo4W\bin\QtWebKit4.dll c:\myapp\

copy c:\OSGeo4W\bin\zlib_osgeo.dll c:\myapp\
copy c:\OSGeo4W\bin\msvcr71.dll c:\myapp\
copy c:\OSGeo4W\bin\phonon4.dll c:\myapp\
copy c:\OSGeo4W\bin\proj.dll c:\myapp\
copy c:\OSGeo4W\bin\geos_c.dll c:\myapp\
copy c:\OSGeo4W\bin\gdal110.dll c:\myapp\
copy c:\OSGeo4W\bin\ogdi_32b1.dll c:\myapp\
copy c:\OSGeo4W\bin\libexpat.dll c:\myapp\
copy c:\OSGeo4W\bin\xerces-c_3_1.dll c:\myapp\
copy c:\OSGeo4W\bin\LIBPQ.dll c:\myapp\
copy c:\OSGeo4W\bin\SSLEAY32.dll c:\myapp\
copy c:\OSGeo4W\bin\LIBEAY32.dll c:\myapp\
copy c:\OSGeo4W\bin\krb5_32.dll c:\myapp\
copy c:\OSGeo4W\bin\comerr32.dll c:\myapp\
copy c:\OSGeo4W\bin\k5sprt32.dll c:\myapp\
copy c:\OSGeo4W\bin\gssapi32.dll c:\myapp\
copy c:\OSGeo4W\bin\hdf_fw.dll c:\myapp\
copy c:\OSGeo4W\bin\mfhdf_fw.dll c:\myapp\
copy c:\OSGeo4W\bin\jpeg_osgeo.dll c:\myapp\
copy c:\OSGeo4W\bin\jpeg12_osgeo.dll c:\myapp\
copy c:\OSGeo4W\bin\netcdf.dll c:\myapp\
copy c:\OSGeo4W\bin\geotiff.dll c:\myapp\
copy c:\OSGeo4W\bin\libtiff.dll c:\myapp\
copy c:\OSGeo4W\bin\sqlite3.dll c:\myapp\
copy c:\OSGeo4W\bin\spatialite4.dll c:\myapp\
copy c:\OSGeo4W\bin\freexl.dll c:\myapp\
copy c:\OSGeo4W\bin\iconv.dll c:\myapp\
copy c:\OSGeo4W\bin\libxml2.dll c:\myapp\
copy c:\OSGeo4W\bin\LIBMYSQL.dll c:\myapp\
copy c:\OSGeo4W\bin\hdf5.dll c:\myapp\
copy c:\OSGeo4W\bin\szip.dll c:\myapp\
copy c:\OSGeo4W\bin\libcurl.dll c:\myapp\
copy c:\OSGeo4W\bin\zlib1.dll c:\myapp\
copy c:\OSGeo4W\bin\openjp2.dll c:\myapp\
copy c:\OSGeo4W\bin\spatialindex1.dll c:\myapp\
copy c:\OSGeo4W\bin\qwt5.dll c:\myapp\

copy c:\OSGeo4W\apps\qt4\plugins\iconengines\qsvgicon4.dll c:\myapp\iconengines\

copy C:\Progra~1\Git\bin\libiconv-2.dll c:\myapp\
copy C:\Progra~1\Git\bin\libintl-8.dll c:\myapp\

copy c:\OSGeo4W\apps\qgis-dev\bin\qgis_Core.dll c:\myapp\
copy c:\OSGeo4W\apps\qgis-dev\bin\qgis_gui.dll c:\myapp\
copy c:\OSGeo4W\apps\qgis-dev\bin\msvcp90.dll c:\myapp\

copy c:\windows\system32\msvcp100.dll c:\myapp\
copy c:\windows\system32\msvcr100.dll c:\myapp\

copy C:\OSGeo4W\apps\qgis-dev\resources\* c:\myapp\qgis\resources
copy C:\OSGeo4W\apps\qgis-dev\plugins\* c:\myapp\qgis\plugins

To be able to run the app, on a fresh windows XP, I had to install:

And copy the whole folder c:\myapp from the building machine to the target machine.

It seems that from Vista, the 2005 redistributable package is included. So, no need to install it.

And voilà!

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NTv2 transformations with QGIS

Datum transformations with grid shift files are used in several countries to convert coordinates between different datums. In Switzerland, datum transformation using the NTv2 method is important because of the upcoming conversion between the LV03 system and the new LV95 system. Up to now, doing coordinate transformations with grid shift files was possible in QGIS, but unconvenient. To use an NTv2 transformation in QGIS, the grid shift file needs to be placed in a directory where proj4 can find it (usually /usr/share/proj on Linux and OSGeo4W\share\proj on Windows).
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Finger Tired From Digitising? Try AutoTrace

My first brush with GIS was back in 2004. I was just getting into building river models and spent a considerable amount of time digitising model inputs. These would often include tens and sometimes hundreds of kilometres of river banks. Many of the input features (e.g. flood embankments) would be traced to snap exactly to existing polygon features.

This was not a big issue at the time as MapInfo had a really nice autotrace feature which made these tasks a doddle. However, when I moved to QGIS I could not find such a feature.

AutoTrace in Action

The image above shows AutoTrace in action. Please see the AutoTrace project page for full documentation and a list of co-funders.

Origins of AutoTrace Development

The idea to develop a plugin to do MapInfo-style tracing was born at the QGIS developer conference (AKA Hackfest) in Lisbon in early 2011. It was there that Paolo Cavalini pointed me towards the traceDigitize plugin already developed by Cédric Möri. traceDigitize already supported tracing but required the user to move the cursor along the edge of the feature being traced. I still had my heart set on achieving that MapInfo-style tracing.

Rather than re-inventing the wheel, traceDigitize was modified to add MapInfo-style tracing as an optional component. This was my development focus for the HF (and the flight back). At this stage the basic functionality was in-place but the plugin had many bugs and was not reliable to use. Unfortunately the plugin was mothballed until recently.

Release of AutoTrace

It was at the first QGIS UK User Group that I met Matt Travis (GIS Officer at Dartmoor NPA) and we got talking about AutoTrace. It transpired that there were a number of local government organisations interested in getting this auto-tracing functionality into QGIS. We soon had commitment from a number of organisations (including and organised by Kevin Williams at Neath Port Talbot Council) to fund the work required to release a stable version of the tool.

Future Plans

There's talk of extending the functionality of AutoTrace to also implement some of he more complex tracing techniques seen in ArcGIS. If this is something you'd be interested in then please let us know.

Many thanks to all those who have supported us in this project.

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Get it on Google Play Get it on Apple store
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PyQGIS Programmer's Guide Available

The preview release of the PyQGIS Programmer’s Guide is now available for purchase from Locate Press.
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QGIS Training Opportunities

We’re planning a couple of training classes for March: Introduction to QGIS Extending QGIS with Python Each is a one day class and we plan to run them back to back. If you are local or just want to come to Alaska in March for some spring skiing, northern lights viewing, or to experience the equinox, please hop over to GeoApt and let us know so we can plan accordingly.
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Multithreaded rendering with QGIS

Nowadays, most computers have several processor cores. However, most computer programs are still designed to only use one processing unit. As a convenient and portable way of writing software using all the available processing power, Qt provides the excellent QtConcurrent framework. In 2010, a Google Summer of Code project examined the suitabilty of using Qt concurrent for rendering the map image in QGIS using several processor cores. Following that approach, each layer renders its image in a separate thread.
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Getting Paths with PyQGIS

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Lutra Co-host QGIS Developer Conference

Lutra Consulting and the University of Sussex are proud to host the 10th developer conference (or Hackfest) on the 12th to 16th of September. QGIS is a powerful and user-friendly Free and Open Source GIS capable of viewing, analysing and mapping Geographic Information.

The adoption of QGIS is accelerating globally in public, private and academic organisations. Developers from around the globe will meet in person to discuss, plan and implement various aspects of the QGIS project.

All university staff and students are welcome to join the Hackfest and meet the people behind QGIS! See the wiki page for more information.

Ongoing news and updates will be posted to this page during the hackfest.

Day 1

Live streaming can be viewed here

Find us here

</p>

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