I have a road network linking multiple (ca 1830) agricultural production regions to several ports (ca 12). (lines in the pic below are roads, small black dots centroids for producing regions and larger dots ports)
I would like to calculate the road path of shortest distance from each production region to each port. For each road connection I would then like to calculate a cumulative "cost" (really risk in this case) for travelling that road based on spatial distribution of flood risk (I have the risk data in both raster and vector format), values ranging from 0 to 1 (low to high risk: white to dark blue in the image below).
I have tried calculating nearest way to port using QNEAT3, but it only provides me with distance, and not the pathway with the physical road travelled (and so I cant use it for calculating the cumulative risk value). and even if it did provide me with the actual physical shortest roads, I don't seem to find a great way to calculate cumulative values along multiple lines.
Does anyone know how to solve this?