Wikipedia:Graphics Lab/Resources/QGIS/Reprojection
—Contribute to this tutorial by completing one section welcome !
Add a plugin (100%)
Most plugin are in the repositories.
- QGis > Plugins > Fetch python plugins (a window pop up)
- > tab "Repositories" > Add 3rd party repositories > ok.
- > tab "Plugins" > Filter: [YourKeyWord] > (if you see your plugin: click) > Install plugin
Our important plugins: Shaded relief ; SimpleSvg,
- Plugin not in the repository
Extended content
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:This section is about adding a plugin not available through QGis (1.7) > Plugins > Fetch plugins, and thus to install handily. We take the case of QGis SimpleSVG plugin.
SimpleSVG currently save the QGis' screen as a SVG with the correct layer division. This save us a lot a energy for later Inkscape work, especially colorations. SimpleSVG is a plugin currently under developement, Richard Duivenvoorde is looking for ideas for improvement. |
Export GIS Vectors & Raster layers to SVG (100%)
Done - Done, awaiting testing & your feedbacks !

Install the QGIS plugin named "SVGsimple" from the QGIS repository then you can export GIS layers, with both SVG and raster layers, and with a cleanly coded SVG file.
- Which information as item name ?
- QGIS (1.7) > right-click on a layer > Properties > tab "Labels" > check on "Display label" > Field containing labels > (choice your field, likely 'Name').
- Check off "Display label"
SVGsimple will remember the field 'Name' and names the GIS items as such in the SVG. In example the GIS item with the fied 'name' being 'Amazon river' in QGIS will now become the .xml/.svg item 'Amazon river' in Inkscape.
- Export as SVG
- QGIS (1.7) > Plugins > Save as SVG > Save as SVG > Choice the pathway > Save > ok.
An clean .svg is produced, with both the raster and vector layers. It is now up to you and Inkscape to change the style of each group / item, and and further content (icons, labels, legend, etc.)
Raster to Vector (polygons) (0%)
→ waiting a volunteer
Concept: Use an elevation GIS file, a discrete black & white colormap, and the Print composer to output one 1500px/1500px black & white png for each altitude (0m, +200m, +500m, etc, name the png accordingly!). This by a cycle such as 1. editing the map color, 2. actualizing the Print composer, 3. outputting the new png. Then use Inkscape to vectorize : load all png, align them, vectorize each using 2 colors + delete background. Color each vector polygon level (0m, 200m, ...) as need.
- Introduction
QGis don't convert raster polygons into vector polygons. It does contours, but which have no fill, and thus, are not suitable.
- QGis cycles
- Inkscape cycles
Projection (0%)
→ waiting a volunteer
Work for both ETOPO1 (world file), small SRTM tile, and merged tiles.
- Source projection
First, you have to find the definition of your source projection/file. It's a kind of long equation which definite the properties of each projection. So:
- QGis (1.7) > (double click on the layer to reproject) > Layer's properties (window pop up) > tab 'Coordinates Reference System (CRS)' > Layer Spatial Reference System : [projection's definition] > (copy it)
Secondly, you have to choice your target projection.
Third, you have to find the definition of this target projection.
- QGis (1.7) > File > Project's properties (a window pop up) > tab 'Coordinates Reference System (CRS)'
- >> Select your target projection* > copy the definition (the long equation) >
- >> ?create a personalized projection.?
- QGis (1.7) > Raster > Warp (reproject) > (a window pop up)
- > fill the fields witht he source SRS, and the target SRS > open in canvas > run > get the result.
- Reproject a raster layer
- Reproject a vector layer
Links

The table above has links to various tutorials and resources which can help in the creation of Wikipedia maps from digital georeferenced data (GIS).
== (I should read before writing) ==
Read:
Travaux impressionnant:
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