I am using QGIS 3.8.1 and I want to compute the shortest path of the centroids of any commune to Paris using the roman network. The centroids are the yellow points the road net is the green lines. There are a lot centroids that are not on the road network. The function Shortest path (layer to point) from Network Analysis worked and I have the cost column with values for all the communes.
However, in case that the centroids are not on the road what does function take into consideration?
The final outcome (Cost column) is in layer units?