Wikipedia:Graphics Lab/Resources/QGIS/Importing OSM roads: Difference between revisions
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==
[[
:{{waiting}} → waiting a volunteer, source: [[:fr:Wikipédia:Atelier_graphique/Didacticiels_cartographiques/Didacticiel_de_création_de_carte_avec_QGIS#T.C3.A9l.C3.A9chargement_des_donn.C3.A9es_compl.C3.A9mentaires|This French section]].
;Concept
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;Applying colormaps
== Translated from French ==
This series of short tutorials designed to learn how to create a [[map]] with [[Quantum GIS]] (QGIS) and possibly [[Inkscape]] in addition.
[[Image: Yeu carte thématique-fr.svg | thumb | 250px | Map of completed [[Île d'Yeu]], carried out without manually draw any line.]]
[[Image: Étapes de création de carte avec QGIS.svg | thumb | 250px | Steps to create card with QGIS - Main steps of creating a map.]]
[[Image: QGIS buttons-fr.png | thumb | 250px | Overview of the QGIS interface view: in red, the important features discussed in this tutorial, some side buttons in orange.]]
QGIS is a [[Geographic Information System | Geographic Information System (GIS)]]. This means that unlike Inkscape, QGIS can manage data files [[geolocation]] and [[geotag]] raw (often in the format [[Tagged Image File Format | TIFF]] and [[shapefile | shp ]]) which can be found on the internet (mostly). Inkscape is a powerful graphical tool that will enhance the files [[SVG]] created by QGIS. Wikipédiennes (in [[Qt Quick. | Qml]]) | from [stylesheets] [stylesheet] will be used for the exported map in QGIS to SVG format is immediately in the style corresponding to [[Help : Mapping # Conventions_et_Recommandations | conventions of Wikipedia]]. This will reduce the level of manual intervention in Inkscape.
To summarize, each of these tutorials is to create a type of [[film]], and each tutorial follows this principle: download raw data → georeferenced application data of a sheet of QGIS style (+ possibly reprojection) → Export SVG by QGIS → valuation in Inkscape (minor corrections, various additions, etc..). (''Note:'' for export in SVG can be, if you will, export all layers at once.)
It may also (depending on card type) use [[Gimp]], [http://www.visualizationsoftware.com/3dem 3DEM] or [http://www.bluemarblegeo.com/global-mapper / Global Mapper].
Reading or at least the overview of the latest manual dated QGIS is strongly recommended ([http://www.qgis.org/fr/documentation/manuels.html]).
{{smalldiv|''prerequisite'' Notions:
* The [[layer]] s QGIS work like [[Layer (computer graphics) | layers]] of [[Inkscape]];
* Highly recommended reading articles [[Tagged Image File Format]] and [[Shapefile]];
* Georeferenced file (either vector or raster) ≠ non-georeferenced file (either vector or raster);
* Graphics software (Inkscape) ≠ [[Geographic Information System | mapping software]] (QGIS can "read" the georeferencing of a file);
* With matrix as well as vector sources, you can create files via QGIS [[bitmap | matrix]] as well as [[image vector | vector]];
* Vector graphics consist of points, lines and polygons (and possibly polylines or relations).
}}
{{smalldiv|''Anglicisms'': Matrix <nowiki>=</nowiki> * <nowiki>=</nowiki> bitmap raster vector ≠ <!-- <nowiki>=</nowiki> prevents "=" from being interpreted by {{smalldiv}} as a parameter -->
* Geographic marker <nowiki>=</nowiki> Geotagging <nowiki>=</nowiki> tag geolocation ≈ attribute (there can be no purely geographical data in attributes). QGIS supports these markers, unlike Inkscape.
* Layer <nowiki>=</nowiki> layer <nowiki>=</nowiki> layer (layer is the literal translation of ''layer'' and was chosen in the translation of QGIS software. ''The term'' layer is perhaps more telling.)
}}
{{Notice| align = center | <small>'''Getting started:''' If you want to start with an easy card, prefer (in order of preference):
* A small-scale (covering a large area), for example more than one department, and less than a country like France (the vector Naturalearth additional data, for a small scale, are the easiest to operate effect , then use the raster gtopo30 for relief, which will also in most cases do not need software 3DEM and Global Mapper);
* Latitude too high (some sources are unavailable for too northern latitudes, northern Scandinavia, Canada, etc, > 60 ° latitude.)
* A map without reprojection necessary, in order to escape this step;
* An area without too many lakes, islands in lakes, ponds on islands in lakes ... and without shoreline or bathymetry (ie without a sea area) (unless you can settle for a curve without sea level) and without depression;
* A bitmap and vector relief is not easy to do, especially if you are not completely familiar with Inkscape.
</small>}}
== Preparation and software ==
'''Install software''' (their installation is very simple in [[Windows XP | XP]] such as [[Linux]])
* [[Image:Logo qgis.png | 30px]] QuantumGIS, http://www.qgis.org/ (no need to install ''North Carolina, South Dakota and Alaska'' data set);
* [[Image:Inkscape_logo_2.svg | 30px]] Inkscape http://inkscape.org/?lang=fr
* (Useful in some cases) [http://www.visualizationsoftware.com/3dem 3DEM] <ref> Visualization Software, publisher of 3DEM, closed in May 2009. 3DEM is still available but it is also kindly provided by [[User: Sémhur | Sémhur]] http://semhur.free.fr/wiki/3dem/3dem_setup.exe </ref> available [http://www.visualizationsoftware.com/3dem on site visualizationsoftware];
* (Useful in some cases) [http://www.bluemarblegeo.com/global-mapper/ Global Mapper];
* (Useful in some cases) [[Image: GIMP_Icon.svg | 40px]] The GNU Image Manipulation program, http://www.gimp.org/.
== QGIS extensions ==
In QGIS, '''install these extensions or check that they are installed''' (''QGIS 1.8 > Extensions > Plugin Installer Python''):
* ''Plugin installer'' (Extension Manager);
* ''GDAL tools'' (tools for processing raster files);
* ''FTools'' (processing tools vector files);
* ''OpenStreetMap plugin'' (OSM files to integrate as layers.)
* ''Polygonizer'' (Polygonize for intersecting segments);
* ''MMQGIS'' (to add a text layer).
Then go to ''Extensions > Extensions Manager'' and '''check extensions''' ''GDAL tools'' and ''OpenStreetMap plugin'' (which are unchecked by default).
'''Install one of these two additional extensions (or both) only if you can not have Linux just long enough to create shaded relief with extension ''Hillshade'' that only works on Linux :'''
* ''DEM terrain shader'', to create a shaded relief (Windows);
* ''Raster Terrain Analysis plugin'', same goal (Windows and Linux).
'''You can install these optional additional extensions:'''
* (Totally optional but interesting) ''Value Tool'', which displays a panel in the altitude of the terrain under the mouse;
* (Optional but interesting) ''SimpleSVG'', which allows you to export very simply view svg displayed in QGIS;
* (Totally optional) ''GRASS'', GRASS tools allow various manipulations;
* (Optional and untested) ''import SRTM elevation for QGIS'' (would, in theory, to download directly from SRTM to QGIS).
{{Hidden| align = center| headerstyle=background:#ccccff | header = ''How to install an extension? What if an extension bug?'' | content=''QGIS 1.8 > Extension > Installer Python > '' extension (a window opens) > seek extensions from the list. Check in ''deposits'' you're connected to deposits tab, check the ''options'' in one of the boxes "show all extensions" tab is selected. Sometimes the extension is installed, but it does not appear or bug (Python error messages), in which case it may be sufficient to re-install (extension tab, select your extension installed, then click on "Re-install" (also check that the extension is checked in the list of the extension manager) Warning, some extensions are very resource intensive: problem may come from a strong lack of memory in your machine.
* If you can not find an extension: ''Extensions > Plugin Installer Python > (a window opens) > Repositories > Add-third deposit extension to the list > '' in the ''Extensions tab'' pick up your extension and install it.
}}
== Download Data ==
[[Image: DatendimensionenImGIS.jpg|thumb|upright=1.3|Size / dimension of the representation of the data]]
{{Main article | Help: Mapping / Map Resources geo}}
== Import data into QGIS ==
[[Image: QGis tutorial - layers toolbar.png|thumb|right|super|upright=1.3|1. Add a Vector layer, 2. Add a Raster layer, 3. Remove Layer(s).]]
Import files using the buttons described below. Each layer imported into QGIS contains a data type (points, lines, polygons). ''Note'': a [[OpenStreetMap]] (specific button) extension .osm corresponds to three layers (points, lines, polygons)..
It is normal for the matrix layer appears gray, since you still have it applied any style. Similarly, each vector layer appears when loaded in QGIS is a random color.
== Provide a projection project ==
{{Main article| Map Projection}}
{{Notice| align = center | <small> If you skip this step, your data will appear in the default projection QGIS (ie lat / lon if you have not changed). Tip: you can skip this step if your area of interest is close to the [[Earth Ecuador | Ecuador]] or if it has a small gap (smaller than [[French district]]). You can also skip this step if you do a test: You can very well create a non-reprojected map, regardless of the area of interest </small>}}.
[[Image: Tissot indicatrix world map equirectangular proj.svg | thumbnail | The deformations of the [[Equirectangular]].]]
'''Enable default projection on the fly.''' It is better, even before loading a layer to activate immediately the projection on the fly: ''QGIS 1.8 > Preferences > Options > SCR > '' Enable ''check on the fly reprojection default''. You can more easily reproject your data. ''Note:'' ''projection EPSG: 4326 - WGS84'' is the default Equirectangular (lat / lon or ''flat''), which "flattens" forms when the area is close to the poles. An equatorial zone will not show unsightly disfigurement.
QGIS displays raster or vector data in the projection you have him '''before''' indicated.
'''To choose a projection to your project''', ''QGIS 1.8 > Preferences > Project Properties > '' select the desired projection in the list. When you import your raster and vector layers in the current project, they should be displayed directly in the right projection (but for rasters you will first a gray rectangle which will be applied later style topographical colors).
To choose the projection or create a custom projection, see [[User:Yug/Projection_sous_QGis_(brouillon)]]
{{Notice | align = center| <small> If the raster does not seem to want to re-project, strictly follow this order (which seems to work better with certain formats): ''QGIS > New Project > tick Enable reprojection'' on the fly default ''> import raster > choose the projection of the project.'' </small>}}
{{Hidden| align = center| headerstyle=background:#ccccff | header=''My data do not appear'' | content=If you have nothing in the preview, this is normal, right-click on the name of layer (in the layer list to the left) and ''zoom to the extent of the layer.'' If so nothing appears, there is a problem with the data or the projection. If you have a gray square this is normal (see below).}}
== Notes ==
<references/>
== To go further ==
Available on the Internet, complete tutorials on Quantum GIS:
* [http://qgis.org/en/documentation/manuals.html official documentation] (Manual for QGIS).
* [http://maps.cga.harvard.edu/qgis/ Tutorial].
Active forums and portals:
* [http://www.forumsig.org/tags.php?tag=qgis GIS forum] (and [http://www.portailsig.org/search/node/qgis GIS portal] associated ).
== See also ==
* [https://plus.google.com/s/qgis QGIS news stream @ Google+]
* [http://www.sourcepole.com/shaded-relief-maps-with-qgis Shaded Relief maps with QGIS]
* [http://underdark.wordpress.com/2012/01/19/a-guide-to-beautiful-reliefs-in-qgis/ A Guide to Beautiful Reliefs in QGIS]
{{Digital cartography tutorials}}
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