Wikipedia:Graphics Lab/Resources/QGIS/Create a topographic background: Difference between revisions

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Latest revision as of 18:51, 20 November 2021

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You already have a GIS file loaded in QGIS, we will now apply to it some nice colors, then output a PNG background for our area of interest and final map.

==Step 4: Add some custom colors==

:''Main page : [[Wikipedia:Graphic Lab/Resources/QGis mapcolor files]] - for more colormap files''

The topographic GIS data you downloaded is by default displayed using a monochromatic palette (mapcolors) going from white to black; however, you have the option of using other colors. You can either load an existing mapcolor file, edit an existing mapcolor file or create your own mapcolors. To do this, you will need to edit the layer's properties.

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Please note that per the Wikipedia [[Wikipedia:WikiProject Maps/Conventions| map conventions]], you should use the colors provided for all topographical shading.

===Existing Wikipedia color palettes===

==Loading mapcolors==

The [[Wikipedia:Graphic Lab/Resources/QGis mapcolor files|QGis mapcolor files]] page already has some palettes you can copy, save as .qml, and use.

;Save your first color style .qml file

:{{done}}— section updated (2012/01)

Copy-paste the following color code in an empty, [[plain text]] document (using something like [[Notepad]] or [[TextEdit]]), then save it in ./QGis/Mapcolors/ as '''Wikicarto_2.0.qml''' (the palette's name + .qml). We will frequently use it later.

{{Collapse|title=Colormap "Wikicarto_2.0.qml"|1=<pre>

<!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>

<qgis version="1.6.0-Copiapo" minimumScale="1" maximumScale="1e+08" hasScaleBasedVisibilityFlag="0">

<transparencyLevelInt>255</transparencyLevelInt>

<rasterproperties>

<mDrawingStyle>SingleBandPseudoColor</mDrawingStyle>

<mColorShadingAlgorithm>ColorRampShader</mColorShadingAlgorithm>

<mInvertColor boolean="false"/>

<mRedBandName>Not Set</mRedBandName>

<mGreenBandName>Not Set</mGreenBandName>

<mBlueBandName>Not Set</mBlueBandName>

<mGrayBandName>Bande 1</mGrayBandName>

<mStandardDeviations>0</mStandardDeviations>

<mUserDefinedRGBMinimumMaximum boolean="false"/>

<mRGBMinimumMaximumEstimated boolean="true"/>

<mUserDefinedGrayMinimumMaximum boolean="false"/>

<mGrayMinimumMaximumEstimated boolean="true"/>

<mContrastEnhancementAlgorithm>StretchToMinimumMaximum</mContrastEnhancementAlgorithm>

<contrastEnhancementMinMaxValues>

<minMaxEntry>

<min>-10458</min>

<max>6741</max>

</minMaxEntry>

</contrastEnhancementMinMaxValues>

<mNoDataValue mValidNoDataValue="false">-9999.000000</mNoDataValue>

<customColorRamp>

<colorRampType>DISCRETE</colorRampType>

<colorRampEntry red="245" value="8000.000000" green="244" blue="242" label="altitude 19 neiges eternelles"/>

<colorRampEntry red="224" value="7000.000000" green="222" blue="216" label="altitude 18 neiges eternelles"/>

<colorRampEntry red="202" value="6000.000000" green="195" blue="184" label="altitude 17 neiges eternelles"/>

<colorRampEntry red="186" value="5000.000000" green="174" blue="154" label="altitude 16 neiges eternelles"/>

<colorRampEntry red="172" value="4000.000000" green="154" blue="124" label="altitude 15 neiges eternelles"/>

<colorRampEntry red="170" value="3000.000000" green="135" blue="83" label="altitude 14"/>

<colorRampEntry red="185" value="2000.000000" green="152" blue="90" label="altitude 13"/>

<colorRampEntry red="195" value="1500.000000" green="167" blue="107" label="altitude 12"/>

<colorRampEntry red="202" value="1000.000000" green="185" blue="130" label="altitude 11"/>

<colorRampEntry red="211" value="800.000000" green="202" blue="157" label="altitude 10"/>

<colorRampEntry red="222" value="600.000000" green="214" blue="163" label="altitude 9"/>

<colorRampEntry red="232" value="400.000000" green="225" blue="182" label="altitude 8"/>

<colorRampEntry red="239" value="300.000000" green="235" blue="192" label="altitude 7"/>

<colorRampEntry red="225" value="200.000000" green="228" blue="181" label="altitude 6"/>

<colorRampEntry red="209" value="150.000000" green="215" blue="171" label="altitude 5"/>

<colorRampEntry red="189" value="100.000000" green="204" blue="150" label="altitude 4"/>

<colorRampEntry red="168" value="50.000000" green="198" blue="143" label="altitude 3"/>

<colorRampEntry red="148" value="20.000000" green="191" blue="139" label="altitude 2"/>

<colorRampEntry red="172" value="1.000000" green="208" blue="165" label="altitude 1"/>

<!-- <colorRampEntry red="167" value="0.000000" green="223" blue="210" label="depression"/> -->

<colorRampEntry red="216" value="0.000000" green="242" blue="254" label="altitude -1"/>

<colorRampEntry red="198" value="-20.000000" green="236" blue="255" label="altitude -2"/>

<colorRampEntry red="185" value="-50.000000" green="227" blue="255" label="altitude -3"/>

<colorRampEntry red="172" value="-100.000000" green="219" blue="251" label="altitude -4"/>

<colorRampEntry red="161" value="-250.000000" green="210" blue="247" label="altitude -5"/>

<colorRampEntry red="150" value="-500.000000" green="201" blue="240" label="altitude -6"/>

<colorRampEntry red="141" value="-750.000000" green="193" blue="234" label="altitude -7"/>

<colorRampEntry red="132" value="-1000.000000" green="185" blue="227" label="altitude -8"/>

<colorRampEntry red="121" value="-2000.000000" green="178" blue="222" label="altitude -9"/>

<colorRampEntry red="113" value="-4000.000000" green="171" blue="216" label="altitude -10"/>

</customColorRamp>

</rasterproperties>

</qgis>

</pre>

}}

More are [[:fr:Wikipédia:Atelier_graphique/Didacticiels_cartographiques/Didacticiel_de_création_de_carte_avec_QGIS#Colorer_les_couches_vecteurs_dans_un_style_wiki|available there]].

===Loading mapcolors===

For this, you will be using the '''Wikicarto_2.0.qml''' file you created earlier in this tutorial.

#:In the ''Layers'' window > Right click on the layer name in> theSelect ''LayersProperties'' window: and select ''Properties''. Thethe ''Layer Properties'''s window will pop up.

# Under the:> ''Symbology'' tab, click> ''Load Style ...'' at the bottom of the window.

#:>> Find and select '''Wikicarto_2.0.qml''', then hit> ''Open''.

# Click:>>> ''OK''. Your map should now be in color!

<gallery widths="500px400px" heights="300px250px">

File:QGis_Load_mapcolor_style_-_01_properties_window.png | The default layer properties window.

File:QGis Print composer output - 06 localizator starting point (correct).png | The final result.

</gallery>

===Editing mapcolors===

[[File:QGis_Load_mapcolor_style_-_02_mapcolor_box.png|thumb|400px|The ''Colormap'' tab with colors already loaded.]]

If you would like to edit already loaded mapcolors, simply go to the ''Colormap'' tab. There, you can add or delete entries by selecting them and clicking the appropriate buttons. You can also edit the ''Value'', ''Color'', and ''Label'' fields of any entry by simply double clicking on the field you wish to change. Click ''Apply'' to see the changes.

===Creating mapcolors===

If you would like to create your own colors from scratch—this is advised against for topographical maps, which should follow the [[Wikipedia:WikiProject Maps/Conventions| map conventions]]—you— you can do so by following these steps on a layer which has not had colors loaded onto it:

# Access the ''Layer Properties''.

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# ''Apply'' or ''OK'' to see the changes.

===Saving mapcolors===

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%) ==

==Existing color palettes==

:{{in progress|— concept ok, screenshot welcome (Fetch python plugins' window).}}

The [[Wikipedia:Graphic Lab/Resources/QGis mapcolor files|QGis mapcolor files]] page already has some palettes you can use. Simply copy-paste the code into a text document, then save as PALETTENAME'''.qml''' and follow the steps above to load it into your map.

The most convenient way to output a high quality topographic background is to use the SimpleSVG plugin.

;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

== Output a background ==

{{Collapse|1=

The most convenient way is to use the SimpleSVG plugin. See next lesson.

:''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.

}}

== Step 6: Output my topographic background ==

=== SimpleSVG plugin ===

==== Export GIS topographic Raster layers to bitmap file (100%) ====

:{{done}} - Done, awaiting your testing & feedbacks !

[[File:QGis SimpleSVG 01 - field for items names.png|300px|thumb|Setting to output well coded SVGs.]]

[[File:QGisLocation SimpleSVGmaps-Simple SVG-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.]]

<br />

You are now working with QGis, your GIS data—namely, ETOPO1—and your customized palette. To output your first topographic background, '''don't use ''File > Save as Image'', which is a simple screenshot.''' For better quality, use the ''SimpleSVG plugin''. <!-- This step will walk you through outputting a map like the one you see on the right, including a grid and an inset that lets the viewer know where in the world this section is located. -->

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;Run SimpleSVG plugin (when installed):

:QGIS (1.7) > Plugins > Save as SVG > Save as SVG'' > Choice your folder : a vector file AND a bitmap file are produced.

:In later versions of QGIS (2.18) > Web > Save as SVG > Save as SVG

;Tips

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# By default, the canvas of QGIS (geographic area visible in QGis) will become the area printed out.

==== Export GIS Vectors & Raster layers to a well coded SVG (100%) ====

=Links=

:{{done}} - Done, awaiting testing & your feedback !

[[File:QGis SVGsimple 01 - field for items names.png|thumb|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''' and its associated bitmap background.

;Which information as item name ?

SVGsimple doesn't natively know which information should be used to name each group or vector item. You have to tell it:

:QGIS (1.7) > right-click on a layer > Properties > tab "Labels" > check on "Display label" > Field containing labels > (choose 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 field '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 > Choose the path > Save > ok.

An clean .svg file and .png background are produced, thus providing both the raster and vector layers.

;Inkscape works!

It is now up to you and Inkscape to change the style of each svg group / item, and to add further content (icons, labels, legend, etc.)

=== Convert GIS Raster layer to true Vector layer (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 can convert raster polygons into vector polygons (''raster > polygonizer''). It does contours too, which have no fill, and so you must use ''vector > geometry > lines to polygons'' in order to fill them up.

;QGis cycles

;Inkscape cycles

== Links==

{{Digital cartography tutorials}}

[[ru:Википедия:Проект:Картография/Помощь/Векторная физическая карта]]

[[fr:Wikipédia:Atelier_graphique/Didacticiels_cartographiques/Didacticiel_de_création_de_carte_avec_QGIS/Topographie]]