Wikipedia:Graphics Lab/Resources/QGIS/Create a topographic background: Difference between revisions
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You can save edited or created mapcolors as a style file by clicking ''Save Style...'' at the bottom of the ''Layer Properties'' window. This will allow you to apply those mapcolors to another map. If you would like to make colors—whether loaded or created—the default colors for the map, click ''Save As Default''. This will allow you to keep editing or loading different colors while having the option to ''Restore Default Style'' if you don't like the changes you've made.
== Step 5:
=== Add a plugin (100%) ===
The most convenient way is to use the SimpleSVG plugin.▼
:{{in progress|— concept ok, screenshot welcome (Fetch python plugins' window).}}
;Plugin in the repositories
Most plugin are in the repositories.
# QGis > Plugins > Fetch python plugins (a window pops 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, Raster Terrain Analysis (under test), OpenLayer (under test).
;Plugin not in the repository
{{summarization|1=
:''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.''
# Download the plugin > Unzip it.
# Cut-Paste the folder in
#: for Linux : in /home/YOURUSERNAME/.qgis/python/plugins/ (paste me here!)
#: for Windows: somewhere in c:/documents and settings, within the QGis' python plugins folder.
# QGis (1.7) > Plugins > Manage plugins > QGis Plugins Manager (pop up)¹ > search key word (SVG) > check the good plugin + ok
# >> Open a/some vector layers or a project with them >
# >> Plugins > Find your plugin: "Save as SVG" > Save as SVG > Choice your ouput place.
:¹: this window also provide you the address of '''your''' plugin directory !
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 Raster layers to bitmap (100%) ===
:{{Done}} — Yug
▲The most convenient way to output a background is to use the SimpleSVG plugin.
[[File:QGis SimpleSVG 01 - field for items names.png|300px|thumb|Setting to output well coded SVGs.]]
[[File:QGis SimpleSVG 02 - output bitmap & vector (png).png|right|300px|thumb|What we want is this: a high quality topographic output. With QGis and experience, you can get this in about 5 to 10 minutes.]]
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# To give a smooth, gradient-like appearance to the colors, go to ''Layer > Properties > Colormap > Color interpolation'' (at the top), and set it to '''''Linear'''''.
# By default, the canvas of QGIS (geographic area visible in QGis) will become the area printed out.
=== Export GIS Vectors & Raster layers to SVG (100%) ===
:{{done}} - Done, awaiting testing & your feedbacks !
[[File:QGis SVGsimple 01 - field for items names.png|300px|right]]
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 ?
SVGsimple don't natively know which information should be used to name each group or vector item. You have to tell him:
: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}} → waiting for a volunteer
* [http://forum.qgis.org/viewtopic.php?f=2&t=8752 Convert to vector]
* [http://forum.qgis.org/viewtopic.php?f=2&t=7396 Edit polygons]
* [http://www.gdal.org/gdal_contour.html Gdal_contour] ([http://georezo.net/wiki/main/logiciels/gdal/couteau_suisse/gdal_contour fr])
* [http://tavmjong.free.fr/INKSCAPE/MANUAL/html_fr/Trace.html Using TheGIMP (fr)]
'''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.<br />
;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
== Links==
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