I am using SUMO to simulate the LuST scenario from https://github.com/lcodeca/LuSTScenario. However, since the scenario is rather large, I would like to start with a simulation constrained to region of interest. Is there a straight forward way to select such a region and have vehicles only simulated in that part of the map?
You can crop the network either using netedit by selecting the region of interest (change to select mode and then draw a rectangle holding the shift key), then inverting the selection (invert button) and deleting the rest. Or if you already know the boundaries or the edges you want to keep you can use for instance with netconvert --keep-edges.in-boundary minX,minY,maxX,maxY -s large.net.xml -o small.net.xml. See here for more netconvert options.
The next step is cutting the routes, which usually means a call like this:
$SUMO_HOME/tools/route/cutRoutes.py small.net.xml large.rou.xml --routes-output small.rou.xml --orig-net large.net.xml
This will not only remove the edges but also try to adapt departure times.