QGIS Automation – Export Layouts by Looping on Project Layers

layoutsprint-composerpyqgisqgis

I've a QGIS project with several vector layers that I need to be represented in a layout I've prepared one by one.

I can manually make visible and select one layer at a time, so that the layout after a refresh shows the desired layer map and legend (where I've selected only show items in the selected map in the interface).
I'm able to select layers by name, and also 'activate' them, but I'm not finding a way to set visibility and active in a PyQGIS script for the layers one by one to automate the export of the layers maps with the layout.

Best Answer

There is a solution to roll on layer you use in your qgis project.

It is based on a mix between this answer and this answer.

The goal is to bend the atlas function to roll to the layer you have in your project.

set the name of the layers to be all different.
create a layer that is named atlas as non geographic layer with no attribute. Then create as many features in this layer as there is layer in your project.
open a layout, then add your map frame. Then activate atlas and use the layer created before as atlas coverage. Then in the map propreties > Layers set the layers to be locked and to be data driven.

Then an expression helper pops out. Set it to give the name of each layer in your project based on the atlas number. This formula may work well :

layer_property(array_get(@layers, @atlas_featurenumber -1) , 'name')

Then you may set the name of the atlas page or anything else and export the atlas.

Related Solutions

[GIS] Print Composer Map with Table using PyQGIS

Which version of QGIS are you using? If it's 2.4, you can set the columns shown in a QgsComposerAttributeTable by using the setColumns method. This method takes a list of QgsComposerTableColumn. Here's an example

#create a composition and composer attribute table
composition = QgsComposition(iface.mapCanvas().mapSettings())
table = QgsComposerAttributeTable(composition)

#create columns for the table
col1 = QgsComposerTableColumn()
col1.setAttribute('feature_id')
col2 = QgsComposerTableColumn()
col2.setAttribute('feature_name')

#set table columns
table.setColumns([col1, col2])

There's a bunch of other things you can set for columns, such as the heading, alignment and sort order (see api docs here). You can even set an expression for a column in place of the attribute for added flexibility.

edit: To show only certain features you can set a filter on the table:

table.setFeatureFilter("id in (1,2,3)")
table.setFilterFeatures( True )

So, to filter a table to only selected features:

#get current layer
current_layer = qgis.utils.iface.mapCanvas().currentLayer()
#get list of selected feature ids
selected_ids = [f.id() for f in current_layer.selectedFeatures()]
#convert list to string
filter_id_string = ','.join([str(id) for id in selected_ids])
#filter table
table.setFeatureFilter("$id in (" + filter_id_string + ")")
table.setFilterFeatures( True )

update: I missed a character in the filter expression. It should have been "$id in (...". Here's a complete, working version of the code you posted. There was a few simple mistakes (the constructor for QgsLegendModel takes no arguments, there's no applyDefaultSize method for attribute tables, and I've also moved the attribute table setItemPosition line):

from PyQt4.QtCore import *
from PyQt4.QtGui import *

layer = qgis.utils.iface.activeLayer()

qgis.utils.iface.actionZoomToSelected().trigger()
qgis.utils.iface.mapCanvas().zoomScale(1000)

mapRenderer = iface.mapCanvas().mapRenderer()
c = QgsComposition(mapRenderer)
c.setPlotStyle(QgsComposition.Print)
x, y = 0, 0
w, h = c.paperWidth(), c.paperHeight()
composerMap = QgsComposerMap(c, x,y,w*.75,h)
c.addItem(composerMap)

legend = QgsComposerLegend(c)
c.addComposerLegend(legend)
legend.model().setLayerSet(mapRenderer.layerSet())
legend.setTitle('')

legendModel = QgsLegendModel()
legendModel.setLayerSet([layer.id()])

legend.updateLegend()

selected_ids = [f.id() for f in layer.selectedFeatures()]
filter_id_string = ','.join([str(id) for id in selected_ids])

table = QgsComposerAttributeTable(c)
table.setItemPosition(x+50, y+50)
table.setVectorLayer(layer)
table.setMaximumNumberOfFeatures(20)
table.setFeatureFilter("$id in (" + filter_id_string + ")")
table.setFilterFeatures(True)
col1 = QgsComposerTableColumn()
col1.setAttribute('Diametre')
col1.setHeading("Diametre")
col2 = QgsComposerTableColumn()
col2.setAttribute('Nature')
col2.setHeading("Nature")
table.setColumns([col1, col2])
c.addItem(table)

printer = QPrinter()
printer.setOutputFormat(QPrinter.PdfFormat)
printer.setOutputFileName('out.pdf')
printer.setPaperSize(QSizeF(c.paperWidth(), c.paperHeight()), QPrinter.Millimeter)
printer.setFullPage(True)
printer.setColorMode(QPrinter.Color)
printer.setResolution(c.printResolution())
pdfPainter = QPainter(printer)
paperRectMM = printer.pageRect(QPrinter.Millimeter)
paperRectPixel = printer.pageRect(QPrinter.DevicePixel)
c.render(pdfPainter, paperRectPixel, paperRectMM)
pdfPainter.end()

PyQGIS – Exporting Filtered Atlas Layout for Print Composer

OK got it. I was missing the setFilterFeatures method. So the updated script is:

manager = QgsProject.instance().layoutManager()

layout = manager.layoutByName("layout")
atlas = layout.atlas()

atlas.setFilterFeatures(True)
atlas.setFilterExpression(''' "continent" = 'europe' ''')

atlas.beginRender()

for i in range(0, atlas.count()):
    exporter = QgsLayoutExporter(atlas.layout())
    print(atlas.filterExpression())
    exporter.exportToPdf('destination_folder' + atlas.currentFilename() + ".pdf", QgsLayoutExporter.PdfExportSettings())
    atlas.next()

atlas.endRender()

Best Answer

Related Solutions

[GIS] Print Composer Map with Table using PyQGIS

PyQGIS – Exporting Filtered Atlas Layout for Print Composer

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