PyQGIS: Create and Print a Map Layout with Python

With the PyQGIS API you are able to use Python in QGIS to automate the creation of map layouts. There are two reasons this is really awesome! First, once you’ve written the initial code to set up the map, you can change map symbology or map layers and exactly replicate layout. Second, once you have the script developed you can create a map at the click of a button. You only have to develop a layout once, and don’t have to worry about accidentally making changes to it.

Because this is a complicated process, I haven’t written a full blog post on it. Instead I’ve provided the code below, and a video that walks through the process step-by-step.

For best results, watch the explanation of the process in the video at the end of this post. You can copy and paste the code below. Be sure to change layer name to match the layer you wish to display.

from qgis.PyQt import QtGui

layers = QgsProject.instance().mapLayersByName('stream_order')
layer = layers[0]

project = QgsProject.instance()
manager = project.layoutManager()
layoutName = 'Layout1'
layouts_list = manager.printLayouts()
# remove any duplicate layouts
for layout in layouts_list:
    if layout.name() == layoutName:
        manager.removeLayout(layout)
layout = QgsPrintLayout(project)
layout.initializeDefaults()
layout.setName(layoutName)
manager.addLayout(layout)

# create map item in the layout
map = QgsLayoutItemMap(layout)
map.setRect(20, 20, 20, 20)

# set the map extent
ms = QgsMapSettings()
ms.setLayers([layer]) # set layers to be mapped
rect = QgsRectangle(ms.fullExtent())
rect.scale(1.0)
ms.setExtent(rect)
map.setExtent(rect)
map.setBackgroundColor(QColor(255, 255, 255, 0))
layout.addLayoutItem(map)

map.attemptMove(QgsLayoutPoint(5, 20, QgsUnitTypes.LayoutMillimeters))
map.attemptResize(QgsLayoutSize(180, 180, QgsUnitTypes.LayoutMillimeters))

legend = QgsLayoutItemLegend(layout)
legend.setTitle("Legend")
layerTree = QgsLayerTree()
layerTree.addLayer(layer)
legend.model().setRootGroup(layerTree)
layout.addLayoutItem(legend)
legend.attemptMove(QgsLayoutPoint(230, 15, QgsUnitTypes.LayoutMillimeters))

scalebar = QgsLayoutItemScaleBar(layout)
scalebar.setStyle('Line Ticks Up')
scalebar.setUnits(QgsUnitTypes.DistanceKilometers)
scalebar.setNumberOfSegments(4)
scalebar.setNumberOfSegmentsLeft(0)
scalebar.setUnitsPerSegment(0.5)
scalebar.setLinkedMap(map)
scalebar.setUnitLabel('km')
scalebar.setFont(QFont('Arial', 14))
scalebar.update()
layout.addLayoutItem(scalebar)
scalebar.attemptMove(QgsLayoutPoint(220, 190, QgsUnitTypes.LayoutMillimeters))

title = QgsLayoutItemLabel(layout)
title.setText("My Title")
title.setFont(QFont('Arial', 24))
title.adjustSizeToText()
layout.addLayoutItem(title)
title.attemptMove(QgsLayoutPoint(10, 5, QgsUnitTypes.LayoutMillimeters))

layout = manager.layoutByName(layoutName)
exporter = QgsLayoutExporter(layout)

fn = 'C:/temp/layout_export.pdf'
#exporter.exportToImage(fn, QgsLayoutExporter.ImageExportSettings())
exporter.exportToPdf(fn, QgsLayoutExporter.PdfExportSettings())