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Next Faunalia Piazza Garibaldi 5 - Pontedera (PI), Italy www.faunalia.it Co-author: Leonardo Lami Introduction GRASS is certainly the reference for GIS analyses in the open source world, as it allows advanced vector and raster analyses. As with most analytical programs, its approach is sometimes hard for the novice (although its graphical interface has improved a lot, and still continues to grow). A number of projects have therefore been born to make life easier for the user. Among these, besides a number of minor projects, several are ready for production use, eg uDIG, gvSIG, OpenJUMP, and especially QuantumGIS. The good thing is that interoperability among different pieces of free software is very high, as it normally happens with open source programs. The user can therefore leverage on the strong points for each program, switching back and forth among several programs, concentrating on data structures and selecting the best tool for each work. Why QuantumGIS QuantumGIS (in short QGIS) is now probably the most attractive free and open source desktop mapping application. Its design is particularly easy to understand from the first approach, thanks to the work of its developers and to the base development libraries used (Qt: http://www.trolltech.com/), basis of the popular KDE Linux desktop environment, and used by important companies like Adobe, ARM, Boeing, Bosch, ChevronTexaco, Daimler Chrysler, Deutsche Telekom, Earth Decision Sciences, HP, IBM, Lockheed Martin, Michelin, NASA, NEC, Pioneer, Scania, Sharp, Shell, Siemens, Skype, Sony, STN-Atlas. A short story Quantum GIS was created in June 2002 by Gary Sherman. After 1.5 years, in which the basis of the structure have been laid out, the development pace has increased considerably, starting from early 2004 (Fig 1 [file figura_01.png]). Developers are numerous, and widespread throughout the world (Fig 2 [file figura_02.png]). The project has been incubated in the popular SourceForge framework for open source projects (http://sourceforge.net), but has now its own structure, with a web site (http://www.qgis.org), where anybody can know more, get the program and the documentation, news, tips&tricks, interviews, etc. QGIS is now an incubating project in the larger Open Source Geospatial Foundation (OSGEO: http://www.osgeo.org)  There is a good support for users, both free, from the community (via mailing lists and an ad hoc chat channel), and paying, from firms and professionals, at conditions similar to those of any other software.  Base features QGIS strongest point is the good integration with other powerful free GIS software, in particular GRASS, PostGIS, and UMN MapServer. Thanks to this, standard functions go well beyond those that could be expected from a desktop mapping program. Multi-platform QGIS has been translated in several different languages, and more can be added with a minimal effort, thanks to code openness. It is available for Linux (where it is mainly developed), but also for all other popular platforms, including Windows and MacOSX. Main functions The interface looks rather familiar to most GIS users; it is easy to find the desired functions, and to activate the many visualization options (Fig 3 [file figura_03.png]). QGIS can read rasters (including TIFF, JPG, ArcInfo grids, DEM, etc., for a total of more than 50 different formats) and vectors (including ESRI shapefiles, ArcInfo binary coverage, MapInfo, SDTS, etc., for a total of more than 20 different formats). One important feature is the capability of reading and writing geodatabase (PostGIS) data, both local and remote. It can also read Web Services (WMS and WFS, standard OGC). This allows the user to bring on common ground a variety of different data, thus acting as a powerful integrator.  It is possible to manipulate RGB colour bands of rasters, visualizing them in greyscale or pseudocolor and set a transparency level (Fig. 4 [file figura_04.png]); loading data can be made faster by pyramidizing the original rasters (this can be done within QGIS). It is also possible to plot the color histogram (Fig. 5 [file figura_05.png]).   Symbology management for vectors is extensive: colours and patterns for filling and outlining can be selected, also in relation to table values; labels can be shown, and attributes can be shown and queried from the tabular data (with a graphical front-end to SQL queries) and from the map; selected records are highlighted both in the table and in the map (Fig 6 [file figura_06.png]).  Another useful function allows to start an external program with a click of the mouse on a feature, based on the content of of a field of the table associated to the vector; if, for instance, we link a series of pictures to a list of points, it is possible to recall a visualization program that will show automagically the associated image (Fig 7 [file figura_07.png]).  Vector editing is possible, in various ways: shapefiles can be modified (with some limitation), as well as PostGIS geodatabase layers (PostGIS advanced digitizing is under heavy development in this period). For heavy duty digitizing, however, the best available option is the GRASS plugin; this allows to display the layers includes in the various Location and Mapset (the GRASS directory structure) and to edit vectors with an interface similar to that of GRASS, though more intuitive (Fig 8 [file figura_08.png]). With the GRASS plugin, digitalization is fully and natively topological, which prevents errors (self-intersections, dangles, etc.) to creep in your precious maps. Page 1 of 2
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