Wikipedia:Graphics Lab/Resources/QGIS/Get ready: Difference between revisions

Revision as of 09:16, 10 June 2011

Revision as of 22:47, 10 June 2011

Line 1:

[[File:QGis_Print_composer_output_-_06_localizator_starting_point_(correct).png|thumb|300px|The QGis interface. QGis can import GIS data—high quality topographic backgrounds, shaded reliefs, and administrative regions or borders—and apply styles to them.]]

'''QGis''' (full name: '''[[Quantum GIS]]''') is a GPL license, cross platform (Window, Linux, Mac), and rather friendly cartographic software making use of the [[Geographic Information Systems]] (GIS). Basically, the GIS is the concept to associate to each geographic coordinate (dot) on the Earth a specific value from some survey. The best know example is altitude, the associate GIS file is a map of the Earth in which each pixel also carry information about its altitude. Reversely, an object can be placed on the Earth, and associated with specific coordinates, commonly roads, parks' shapes, lakes and rivers, states, provinces, urban areas, etc, and are georeferenced layers matching precisely.<br />This approach radically change the way of mapmaking. The mapmaker/graphist formerly had to draw himself from A to Z each layer of the map and combine them. It work's reliability was limited and precision was limited by the mapmakers resources and knowledge. Now, these precise GIS data/files can be collected by the mapmaker who have to load his selection of GIS files into a GIS software such QGis, with objects automatically placed to their exact coordinates, apply custom styles, and output a basemap which may be the end product, or a background to host the last layers of custom works (icons, labels, legend, etc.).<br />

[[File:Washington_topographic_map-fr.svg|300px|thumb|Map with imported GIS data: topographic background, shaded relief, administrative borders, and [[OpenStreetMap]] roads. The labels, icons, and legend are easily added later using [[Inkscape]].]]

For Wikipedia, the advantage of GIS maps are precision, reliability, and upgrade in visual elegance for our maps. It will be mainly '''useful to generate topographic background (png, svg), shaded reliefs (png), and administrative regions or borders (png, svg), and apply style to them'''. While [[GRASS GIS]] seems still to be the most common GIS software, its usage is quite rude (mainly [[console line]]). Also, beginners will prefer [[QGis]], which is quite powerful, human friendly, integrate GRASS GIS and [[GDAL]], is used as a graphical user interface of GRASS GIS, and still have a lot of space to improve your GIS mapmaking skills.<br />

This tutorial series focus on '''how to use QGis to generate reliable maps for wikipedia'''. Accordingly, it is Wikipedia centered : outputting general public encyclopedic maps ; and follow the [[Wikipedia:WikiProject_Maps/Conventions|Wikipedia map conventions]].

'''QGis''' (full name: '''[[Quantum GIS]]''') is a [[GPL license]], cross-platform ([[Windows]], [[Linux]], [[Mac OS|Mac]]), and rather friendly cartographic software application. It is a [[Geographic information system|Geographic Information System]] (GIS) you can use to create, view, and analyze maps. In a nutshell, a GIS associates with each geographic coordinate (dot) on Earth a specific value from some survey. The best example of this is altitude: a [[topographic map]], like the ones you see below, can be created from a GIS file in which each pixel also carries information about its altitude. Reversely, objects can be placed on a map and associated with specific coordinates; this is commonly used for features such as roads, lakes, state or province borders, urban areas, etc. As a result, these features are [[wikt:georeferenced|georeferenced]] on separate layers and their shape and ___location match their actual appearance on the surface of the Earth.

<center>

{|

This approach radically changes the process of making maps. Formerly, the mapmaker or graphist had to personally draw each layer of a map, then combine them into an image. The work's reliability and precision were limited by the user's resources and knowledge. Now, the mapmaker can collect precise GIS data from reliable sources and simply load them into QGis. Objects will be automatically placed in their exact coordinates, allowing the user to apply custom styles and output an accurate basemap, which may be the end product, or a background to host additional custom layers (icons, labels, a legend, etc.). For Wikipedia, the advantages of GIS maps are precision, reliability, consistency, and an upgrade in visual elegance of the final images. Using QGis will be mainly helpful in generating '''topographic backgrounds (png, svg), shaded reliefs (png), and administrative regions or borders (png, svg)''', and applying various styles to them.

| [[File:QGis_Print_composer_output_-_06_localizator_starting_point_(correct).png|thumb|500px|center|Example of QGis. QGis can import GIS data : hight quality topographic background (png, svg), shaded reliefs (png), administrative regions or borders (png, svg), and apply style to them]] || [[File:Washington_topographic_map-fr.svg|400px|thumb|Map with imported GIS data : the topographic background, shaded relief, administrative borders, and [[OSM]] roads. The labels, icons, and legend are them later added handily using [[Inkscape]].]]

|}

While [[GRASS GIS]] still seems to be the most common GIS software, it has a primarily [[command-line interface]] and can be difficult to learn and operate. Therefore, beginners will prefer [[QGis]], which is quite powerful and user-friendly. It integrates GRASS GIS and [[GDAL]] data, provides an [[graphical user interface|easier to use interface]] than GRASS GIS, and gives the user an opportunity to improve his or her GIS mapmaking skills.

</center>

This tutorial series focuswill onteach you '''how to use QGis to generate reliable maps for wikipediaWikipedia'''. Accordingly, it is Wikipedia centered :and focuses on outputting general public encyclopedic maps ; andwhile followfollowing the [[Wikipedia:WikiProject_Maps/Conventions|Wikipedia map conventions]].

=== The tools ===