PyQGIS – How to Export Map to Image Using PyQGIS

Question

I have a transparent raster on top of a hillshade.

I want to Project – Import/Export – Export map to image using PyQGIS:

I need to be able to set extent, scale, dpi and the output needs to be georeferenced.

I have followed PyQGIS: Render (Print/Save) a Layer as an Image to get an output but the output has no coordinate system set.

How can I export the image including this?

img = QImage(QSize(3000, 3000), QImage.Format_ARGB32_Premultiplied)
img.setDotsPerMeterX(1)
img.setDotsPerMeterY(1)

# create map settings
ms = QgsMapSettings()

# create painter
p = QPainter()
p.begin(img)
p.setRenderHint(QPainter.Antialiasing)

# set layers to render
layers = list(reversed([lyr for lyr in QgsProject.instance().mapLayers().values()]))
ms.setLayers(layers)

# set extent
rect = iface.mapCanvas().extent()
rect.scale(1.1)
ms.setExtent(rect)

# set ouptut size
ms.setOutputSize(img.size())

# setup qgis map renderer
render = QgsMapRendererCustomPainterJob(ms, p)
render.start()
render.waitForFinished()
p.end()

# save the image
img.save('/home/bera/Desktop/test_render.png')

print('Done')

Answer 1

You can create an external world file, which provides the georeferencing information for the raster image you export.

...

# save the image
img.save('/home/bera/Desktop/test_render.png')

# world file content
pgw_content = QgsMapSettingsUtils.worldFileContent(ms)

with open('/home/bera/Desktop/test_render.pgw', "w") as f:
    f.write(pgw_content)

print('Done')