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geoinf18:qgsmaprendererjob
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geoinf18:qgsmaprendererjob [2018/11/13 17:33] oertz created |
geoinf18:qgsmaprendererjob [2018/11/13 18:04] (current) oertz |
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| ==== Tutoriel "QGIS map renderer" ==== | ==== Tutoriel "QGIS map renderer" ==== | ||
| - | Objectif : comprendre le "portrayal model" {{:ogo13:portrayalogc.png?linkonly|}} par l'utilisation du **moteur de rendu cartographique** de QGIS3 avec [[https://qgis.org/pyqgis/master/core/Map/QgsMapRendererSequentialJob.html|QgsMapRendererSequentialJob]] et [[https://qgis.org/pyqgis/master/core/Map/QgsMapSettings.html|QgsMapSettings]] | + | **Objectif** : comprendre le "portrayal model" {{:ogo13:portrayalogc.png?linkonly|}} par l'utilisation du **moteur de rendu cartographique** de **QGIS3** avec sa console Python et les classes [[https://qgis.org/pyqgis/master/core/Map/QgsMapRendererSequentialJob.html|QgsMapRendererSequentialJob]] et [[https://qgis.org/pyqgis/master/core/Map/QgsMapSettings.html|QgsMapSettings]]. |
| - | Remarque : pour les utilisateur de QGIS2, voici le tutoriel [[geoinf15:qgsmaprenderer|QgsMapRenderer 2015]]. | + | {{:ogo13:portrayalogc.png?direct&400|}} |
| + | Pour les utilisateur de **QGIS2**, voici le tutoriel [[geoinf15:qgsmaprenderer|QgsMapRenderer 2015]]. | ||
| + | |||
| + | === Prérequis pour ce tutoriel sur QGIS3 === | ||
| + | |||
| + | * les données //g4districts98// disponible dans le dossier https://drive.switch.ch/index.php/s/jHcUvhFSRwEneES | ||
| + | |||
| + | === Découverte du "map renderer" === | ||
| + | |||
| + | * pour une couche chargée et sélectionnée dans la table des couches, ouvrir la console Python : | ||
| + | |||
| + | <code> | ||
| + | # we work with the selected layer | ||
| + | layer = iface.activeLayer() | ||
| + | |||
| + | # we want to know the current map settings | ||
| + | canvas = iface.mapCanvas() | ||
| + | mapset = canvas.mapSettings() | ||
| + | |||
| + | # we display the mandatory settings to build a map | ||
| + | print(mapset.layerIds()) | ||
| + | print(mapset.extent().asWktPolygon()) | ||
| + | print(mapset.outputSize()) | ||
| + | </code> | ||
| + | |||
| + | === Contrôle du "map renderer" === | ||
| + | |||
| + | * pour prendre le contrôle et exporter dans un fichier image le résultat du rendu cartographique, on ajoute : | ||
| + | |||
| + | <code> | ||
| + | # set layer(s) | ||
| + | mapset.setLayers([layer]) | ||
| + | # set extent | ||
| + | mapset.setExtent(QgsRectangle(530000,180000,550000,200000)) # close to Yverdon | ||
| + | # set output size | ||
| + | mapset.setOutputSize(QSize(800,800)) | ||
| + | |||
| + | # even more, set background color | ||
| + | mapset.setBackgroundColor(QColor(0,0,0,0)) | ||
| + | |||
| + | job = QgsMapRendererSequentialJob(mapset) | ||
| + | job.start() | ||
| + | job.waitForFinished() | ||
| + | img = job.renderedImage() | ||
| + | img.save('/home/olivier/tmp/render.png', 'png') # adapt the path properly | ||
| + | </code> | ||
| + | |||
| + | {{:geoinf18:render.png?nolink&200|}} | ||
geoinf18/qgsmaprendererjob.1542126837.txt.gz · Last modified: 2018/11/13 17:33 by oertz
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