A while ago I did a neighbourhood roof orientation survey for solar panel deployment, by visually checking each roof and marking individually whether they were south or almost south-facing.
As this is very time-consuming, I would like to find a way to automate this, but don't know how this would be possible by merely analysing roof shadows.
I can script a little but have never written any plug-ins.
What other elements do I need to include?
We are on a very low budget, so seek any suggestions how to do this using open source tools.