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Introduction

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 Sytems (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.
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.).
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 political backgrounds (png, svg). While GRASS GIS seems still to be the most common GIS software, it's usage is quite rude (lot of console). 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. thumb|600px|center|Example of QGis. Help to create hight quality topographic background (png, svg), shaded reliefs (png), and political backgrounds (png, svg)

Installation of QGis

sudo apt-get install add-apt-repository 
sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable
sudo apt-get update
sudo apt-get install qgis
Empty folders to create
  • /Desktop/ (or other suitable place)
    • /QGis/
      • /Data ETOPO1
      • /Data_SRTM3 v.2
        • /Shaded
      • /Data_Naturalearth.com
      • /Data_...
      • /My_tutorials
      • /My_mapcolors
      • /My_projects
      • /My_outputs
      • /[other as you need it !]

The /Data_[sourcename] folders are need since each data source may have different copyrights status, coverage quality, subjects (topography ? politic ?), and is usually made of dozens of files/tiles, so create separate data folders make sense. /My_tutorials, /My_mapcolors, /My_projects, /My_outputs will likely be useful too. /My_tutorial will host interesting tutorials (webpages, pdf, etc) you will find, you may also edit them, and take your own notes. /My_mapcolors will host the color styles you will find online or create and save there. /My_projects will host your QGis projects. /My_outputs will host the some dozen of intermediate outputs you will generate and frequently look at to improve yourself through your learning process.

First color style

Copy-paste the following color code in an empty text document, then save in ./QGis/My_mapcolors/ as Wikicarto_2.0.qml. We will frequently use it later.

{{{1}}}
{{{2}}}

GIS data

Template:Voir

Topography
See de:Hilfe:GMT#Topographische_Datens.C3.A4tze
Quality comparison ETOPO1 vs SRTM3 (better). This difference doesn't matter when you make large maps >1000km
Other GIS data
  • NaturalEarthData,com (Public Domain) : collection of GIS data, with:
A. Cultural (human or political including: Countries polygons ; Sub-countries polygons ; Borders lines ; urban areas ) ;
B. Physical (Coastlines, rivers, lakes, bathymetry ; geographic lines) ;
C. Raster background (natural earth II, topographic ; ocean bottom ; shaded relief grey)
http://www.naturalearthdata.com/features/
Which data for YOU

New users will prefer to simply download ETOPO1 for topography. Don't use ETOPO2 which is actually an oldest version (1px = 2km x 2km).

Confirmed mapmakers will use the SRTM/SWBD for its better quality. But they have there to :

  1. Know the coordinates of the area they want to map
  2. Find online these associated GIS files. Files have names such as "N22E112.hgt.zip", standing for 22⁰ North, 112⁰ East.
  3. Download them handly. Some for a small ilsland ; about one hundred for Korea ; + 5 thousands for Eurasia.
  4. Unzip them.
  5. Load them into QGis.

Load the GIS file (layer) into QGis

QGis tutorial video,
watch the first minute.
Load data (topography)

Start QGis > in QGis' topbar, click icon "Add a Raster Layer" > Select the unzipped "ETOPO1_Ice_g_geotiff.tif", .shp, .shx, etc. > open. The data will appear in great by default.
If you have a vector layer to load : click icon "Add a Vector Layer". Etc.

  • Add raster layer
    Add raster layer
  • Topo data appear in grey.
    Topo data appear in grey.

Custom colors

(* Fiches_QGIS v1104.pdf > page 7. )
* ( A palette creator
* [Tutoriels http://sig974.free.fr/?p=198]  )

To set custom colors, it is need to edit the layer's properties. Topographic GIS data are by default displayed using greys : a palette or mapcolor going from white to black. But you can use other paletters/mapcolors. Palettes/mapcolors are a set of colors that you appreciate and generally use.

Since the Graphic labs developped such guidelines for colors, the following mapcolors have been created, and shared, to ease the creation of wiki maps. Enjoy !

Installation

To copy-paste in text document, then save as PALETTENAME.qml. Then, in QGis : LAYER > Properties > Load a style > [browse and select the .qml file]

{{{1}}}
{{{2}}}
{{{1}}}
{{{2}}}

Output : Print composer

What we want is this : an high quality topographic output (you can zoom in !). With QGis and experience, we can get this in about 5 to 10 mins

You are now working with QGis, your GIS data (namely: ETOPO1), your customized palette. To output your first topographic background, don't use File > Save as Image, which is a simple screenshot. For a better quality :

  1. Use the Print composer: QGis (1.6) > File > New print composer (Ctrl+P). First, in this composer window, overfly its topbar icons : one pop up "Add new map". Click this icon, then click&drag on the white area to put the map, then adjust. Second, on the right box : General > Composition > Paper quality > Size > Custom : set the size you want, larger it is, higher will be your output quality !
  2. Smoothing colors: be sure the color style is set to "linear":
QGis (1.6) > Layer > Properties > Colormap > Color interpolation : set on "linear". The output will now be smoother, colors going smoothly from one to another.

Then : Composer > File > Export as image/PDF/SVG, and that's it, an high quality topo background.

Others functionalities

Grids: Within the Print Composer > selecting an item > Item (right side) > Grid > customize as you wish/can. Add icons: user/share/qgis/svg/

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