When and how to restart the router in Route by Zaweba

Behind the map in Route by Zaweba sits a routing engine, a separate program that works out the roads between your stops. Most of the time you never think about it. Map > Restart the router is there for the rare moment when it stops answering or seems stuck, and it is the quickest way to get going again without closing the app.

It helps to know a little about what the router is. Route bundles GraphHopper, a well-known open routing engine, with its own Java runtime. It runs on your PC and can only be reached from that PC. Nothing is sent over a network to work out a route, which is why Route plans just as well with no signal as with one.

Why there is a separate engine at all

Working out good routes over a real road network is heavy work. The engine loads the routing graph that was built when you prepared your map region, and then answers questions from the app: the best road from here to there, the travel time between every pair of stops for Optimise order, the turn-by-turn directions for each leg. Keeping that work in its own process means the window stays responsive while big calculations run.

The price of that design is that two programs have to keep talking to each other. If the engine is busy with something very large, short of memory, or simply gets into a bad state, the app can be left waiting for an answer that does not come. That is the moment for a restart.

When a restart is the right move

Signs that the router needs a restart include a route that will not calculate, a leg that never appears after you drag a via point, or Optimise order that never finishes on a list it would normally handle quickly. If the map itself still pans and zooms but nothing route-related responds, the engine is the likely cause.

Before restarting, give it a fair chance. Very large lists of hundreds of stops take longer to optimise, because the router has to find the travel time between every pair. If you have just asked for a big job, wait a little. If a small job is stuck, restart.

What a restart does and does not touch

Restarting stops the local engine and starts it again with the current map region. It does not affect your stops, their time windows, your via points or your saved routes, so you can restart without fear of losing work. Once it is running again, use Route > Calculate the route to ask for the route afresh.

It does not download anything, change your region or rebuild the map. If a region itself is incomplete, for example because preparation was stopped part-way, the fix is to resume preparation from the region chooser, not to restart the router.

If restarting does not help

If problems come back after a restart, look at the bigger picture. A large region on a PC with little free memory can strain the engine, so closing other heavy programs is worth trying. Check that the stops in your round are inside the region you have loaded, since a stop outside the map cannot be routed to. And if you have moved the regions folder recently, make sure the region you are using is in the place Settings expects.

Saving the round first is a sensible habit before any troubleshooting. File > Save writes your stops, windows, options, set-off time and via points to an .ozroute file, so even closing and reopening Route costs you nothing.

Why this is a menu command rather than a mystery

Many programs hide their moving parts and leave you to close everything when something sticks. Route gives the engine its own restart because it is a real, separate piece of the app, and because planning offline means there is no server somewhere else to blame or wait for. Everything happens on your PC, so the fix is on your PC too, one click away in the Map menu.