The Mapnik Viewer is a GUI tool for rendering and viewing maps based on Mapnik XML mapfiles.

It's available under source:trunk/demo/viewer and needs to be compiled after manually modifying the build settings.


World Population Tutorial XML loaded within Mapnik Viewer

A Desktop XML Viewer

  1. View tile images on-the-fly.
  2. Debug information on bad config files, points to the erroneous line.
  3. Shows scale and envelope for current view.
  4. Fast zooming and point-based attribute queries.
  5. Export to a variety of formats including tif.

Requirements

  • A working Mapnik installation
  • A Mapnik XML file to view
  • Qt4 including dev files (for example, see Qt/Mac Open Source Edition)
  • Qmake

Compiling

  1. Modify viewer.pro to match your system include and lib directories for boost, your mapnik build, unicode, and freetype.
    • Most default installs put the mapnik libs and includes in usr/local, thus requiring an include like: 
      INCLUDEPATH += /usr/local/include/mapnik
    • And a lib like: 
      unix:LIBS += -L/usr/local/lib -lmapnik
    • And to link boost, freetype, and unicode from macports on Mac 10.5, for example, would require: 
      INCLUDEPATH += /opt/local/include/boost-1_35
INCLUDEPATH += /opt/local/include/unicode
INCLUDEPATH += /opt/local/include/freetype2
INCLUDEPATH += /opt/local/include
unix:LIBS +=   -L/opt/local/lib -lfreetype
  • Since Ubuntu 10.04 those settings are enough: 
    QMAKE_CXXFLAGS +=' -ansi'
INCLUDEPATH += /usr/include/freetype2
LIBS += -lmapnik
  1. Modify main.cpp by setting the correct paths to Mapnik's plug-ins and fonts directories
    • Lines 33 - 37
    • On most systems these lines should point to/usr/local/lib/mapnik/ 
      datasource_cache::instance()->register_datasources("/usr/local/lib/mapnik/input"); 
freetype_engine::register_font("/usr/local/lib/mapnik/fonts/DejaVuSans.ttf");
freetype_engine::register_font("/usr/local/lib/mapnik/fonts/DejaVuSans-Bold.ttf");
freetype_engine::register_font("/usr/local/lib/mapnik/fonts/DejaVuSansMono.ttf");
  1. Then run Qmake to generate a makefile (Qmake may also generate an Xcodeproject instead on OS X. Try "qmake -spec macx-g++" instead.) 
    cd mapnik-svn-tree/demo/viewer
qmake -makefile
  1. Finally, run Make to build the viewer.app or viewer.exe 
    make

(On OS X, you may need to instead run "open viewer.xcodeproj" to open the project in Apple's XCode environment.)

  • Your make output should be something like: 
    $ make
make -f Makefile.Release
/opt/local/bin/uic forms/about.ui -o ui_about.h
/opt/local/bin/uic forms/info.ui -o ui_info.h
/opt/local/bin/uic forms/layer_info.ui -o ui_layer_info.h
c++ -c -pipe  -DDARWIN -Os -Wall -W -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/opt/local/share/qt4/mkspecs/macx-g++ -I. -I/opt/local/include/qt4/QtCore -I/opt/local/include/qt4/QtCore -I/opt/local/include/qt4/QtGui -I/opt/local/include/qt4/QtGui -I/opt/local/include/qt4 -I/usr/local/include/mapnik -I/opt/local/include/boost-1_35 -I/opt/local/include/unicode -I/opt/local/include -I/opt/local/include/freetype2 -I. -Irelease -I. -o release/main.o main.cpp
[...]
  • If it fails you need to go back to the viewer.pro and set more lib and include paths
  • A successful build will output the ready to run graphical program in that directory.

Usage

Double click on the resulting application (viewer.app on Mac OS)

  • You can then load map files from the file menu (make sure you have absolute paths set to datasources).
  • Hit the Home button to zoom to the data extent.
  • The rest should be obvious.

You can also load your XML files when launching the viewer from a terminal: 

# On linux this would look like:
# ./viewer /path/to/your.xml
# On mac this would look like:
$ ./viewer.app/Contents/MacOS/viewer /path/to/your.xml
# or
$ open -a viewer

or 

# ./viewer your.xml -1,50,1,52

or 

# ./viewer # (open your.xml from file menu)

Further Reading

Related mailing list discussions:

Attachments