Correct image for each layer via print Layout

Question

In the code, first I am merging the Cooling_Tower(vector layer) with each raster layer and I want the output as an image, so created a layout, add a map, gave extents and page properties, and exported it as an image.

The issue with the code is, that it's only giving the correct image for the last layer and all the other layers are blank white when exporting it as an image.

Is it possible to refresh the map canvas for every new layer and export it as an image or Is there any other possibility to get a correct image for each layer?

from PyQt5.QtCore import QTimer
fileName = 'D:\\UCC\\exported' # exported is a prefix for the file names 
boundaryLayer = QgsProject.instance().mapLayersByName('Cooling_Towers')[0] 
QgsProject.instance().layerTreeRoot().findLayer(boundaryLayer.id()).setItemVisibilityChecked(True) 
otherLayers = [] 
for layer in QgsProject.instance().mapLayers().values(): 
 if layer.name().startswith("M_"): 
 otherLayers.append(layer.name())
count = 0 
def prepareMap(): # Arrange layers
 for layer in QgsProject.instance().mapLayers().values():
 if layer.name().startswith("M_"):
 QgsProject.instance().layerTreeRoot().findLayer(layer).setItemVisibilityChecked(False)
 for layer in QgsProject.instance().mapLayers().values():
 if layer.name().startswith(otherLayers[count]):
 QgsProject.instance().layerTreeRoot().findLayer(layer).setItemVisibilityChecked(True)
 qgis.utils.iface.setActiveLayer(layer)
 qgis.utils.iface.zoomToActiveLayer()
 project = QgsProject.instance()
 manager = project.layoutManager()
 layoutName = 'Layout'
 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)
 
 page_size =QgsLayoutSize(5000, 5000, QgsUnitTypes.LayoutPixels)
 pc = layout.pageCollection()
 page = pc.pages()[0]
 page.setPageSize(page_size)
 # create map item in the layout
 map = QgsLayoutItemMap(layout)
 map.setRect(20, 20, 20, 20)
 # set the map extent
 #ms = QgsMapSettings()
 #ms.setLayers([layer, boundaryLayer]) # set layers to be mapped
 #rect = QgsRectangle(ms.fullExtent())
 rect = QgsRectangle(-8232312.3, 4993694.4, -8231302.8, 4994703.9)
 #ms.setExtent(rect)
 map.setExtent(rect)
 #map.setBackgroundColor(QColor(255, 255, 255, 0))
 layout.addLayoutItem(map)
 #map.attemptMove(QgsLayoutPoint(0, 0, QgsUnitTypes.LayoutMillimeters))
 map.attemptResize(QgsLayoutSize(423.333, 423.333, QgsUnitTypes.LayoutMillimeters))
 layout = manager.layoutByName(layoutName)
 exporter = QgsLayoutExporter(layout)
 fn = 'D:\\layout_export' + str(count) + '.png'
 exporter.exportToImage(fn, QgsLayoutExporter.ImageExportSettings())
 
 QTimer.singleShot(5000, exportMap) # Wait a second and export the map
def exportMap(): # Save the map as a PNG
 global count # We need this because we'll modify its value
 if count < len(otherLayers)-1:
 QTimer.singleShot(10000, prepareMap) 
 count += 1
prepareMap() # Let's start the fun

Reference - Iterating over layers and exporting them as PNG images with PyQGIS in standalone script

https://data.library.virginia.edu/how-to-create-and-export-print-layouts-in-python-for-qgis-3/

Answer 1

Try this:

def exportMap(layer, count): # Arrange layers
 global boundaryLayer # You have to define this layer
 QgsProject.instance().layerTreeRoot().findLayer(layer).setItemVisibilityChecked(True)
 qgis.utils.iface.setActiveLayer(layer)
 qgis.utils.iface.zoomToActiveLayer()
 project = QgsProject.instance()
 manager = project.layoutManager()
 layoutName = 'Layout'
 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)
 
 page_size = QgsLayoutSize(5000, 5000, QgsUnitTypes.LayoutPixels)
 pc = layout.pageCollection()
 page = pc.pages()[0]
 page.setPageSize(page_size)
 # create map item in the layout
 map = QgsLayoutItemMap(layout)
 map.setRect(20, 20, 20, 20)
 map.setKeepLayerSet(True)
 map.setLayers([layer, boundaryLayer]) # set layers to be mapped
 # set the map extent
 rect = QgsRectangle(-8232312.3, 4993694.4, -8231302.8, 4994703.9)
 map.setExtent(rect)
 layout.addLayoutItem(map)
 map.attemptResize(QgsLayoutSize(423.333, 423.333, QgsUnitTypes.LayoutMillimeters))
 exporter = QgsLayoutExporter(layout)
 fn = 'D:\\layout_export' + str(count) + '.png'
 exporter.exportToImage(fn, QgsLayoutExporter.ImageExportSettings())
 
 #QTimer.singleShot(5000, exportMap) # Wait a second and export the map
def runExportMap(): # Save the map as a PNG
 #global count # We need this because we'll modify its value
 count = 1
 for layer in QgsProject.instance().mapLayers().values(): 
 if layer.name().startswith("M_"): 
 exportMap(layer, count)
 count += 1

• kanishka dubey: Thank you for the response. You said 'List of layers you need, meaning? In my case, the boaundary layer and current layer, how can I put them in the list, they are variables? And at which line I must put the script you suggested? @s-chernyshov
• kanishka dubey: I am new to this. I would really appreciate it if you can detail it, please. @S.Chernyshov
• RainForest: You already wrote it: #ms.setLayers([layer, boundaryLayer]). Just set layers for map, not for QgsMapSettings: map.setLayers([layer, boundaryLayer])
• kanishka dubey: I tried the method you suggested, but I am still getting the same issue. @S.Chernyshov
• RainForest: Tried to moidify your code, please check