Preparing big map regions from the command line in Route

Large map regions take a while to prepare, and Route by Zaweba lets you do that job without the app's window open at all. Run ZawebaRoute.exe with --prepare, followed by either a Geofabrik id or the path to an .osm.pbf file, and it prepares that region in the background. It can write a log as it goes, so you can check later what happened.

This is the same preparation the app does when you pick a region from Map > Choose a region. The difference is only in how you start it. For a county that prepares in seconds to minutes, the normal window is easier. For something the size of Great Britain, the command line has real advantages.

Why prepare from the command line

Great Britain is about 2 GB to download and needs roughly 8 GB of free memory to prepare. That is a job you might want to run overnight, at a quiet time, or on a PC you are not sitting at. Starting it from a command means it can be run from a shortcut, a batch file or a scheduled job, rather than by someone clicking through the region chooser.

It also suits anyone who manages several PCs. A command line is easy to repeat exactly, and a log is easy to keep.

The two ways to name a region

A Geofabrik id names one of the extracts in Geofabrik's list, the same list Route shows as a tree of continents, countries and counties. Route downloads the extract and prepares it, exactly as it would from the window.

An .osm.pbf file is an OpenStreetMap extract you already have on disk. Giving its path skips the download and prepares the file directly, the same way Use a map file I already have does in the app. That is useful if you keep extracts on a shared drive, or have one from another source.

What happens while it runs

Preparation runs in steps: download (resumable, and checked against Geofabrik's MD5), the address index, coastline and postcode data when needed, postcodes, the routing graph, then map tiles. Coastal regions also download OpenStreetMap water outlines once, about 0.9 GB.

Each finished step is recorded. If the job is stopped, crashes or the power goes, it carries on from the first unfinished step next time rather than starting again. For a long overnight preparation that matters a great deal: a power cut at three in the morning costs you only the step that was running.

Fitting it into a routine

One tidy way to use it is with a scheduler. Schedule by Zaweba can run a program with arguments on a timetable written in plain English, records the exit code in its history, and can show the program without a window. A job that runs ZawebaRoute.exe --prepare with your region's id late one evening, with a log written alongside, is a neat way to build a big region while you sleep.

Make sure there is room first. The finished region goes into the regions folder set in Settings, and that folder must be outside the app's own folder. Check the drive has space, and that the PC has the free memory a big region needs. If preparation of a large region struggles, the memory setting for building the routing graph and tiles can be raised from automatic in Settings.

Mistakes to avoid

Do not run a command-line preparation of a region while also preparing the same region from the window. Let one finish. Do not delete a part-prepared region's folder because the job was interrupted; resuming is much quicker than starting over. And read the log if something seems wrong, because it records what the engine reported rather than leaving you to guess.

When the job is done, open Route as normal. The region appears in the region chooser as ready, and the map, routing and address search all work offline from then on.