Roadbook '71 takes your recording as the truth. That is the whole design, and it has an obvious consequence: a sloppy recording makes a sloppy roadbook. Not a broken one, since the app is built to cope with real files from real drives, but the difference between a good GPX and a rough one is the difference between diagrams you recognise instantly and diagrams you have to squint at.
None of this is difficult. It is mostly about pressing record before you set off and leaving the phone alone.
What to record with
Anything that writes a GPX will work. In rough order of how well they suit this particular job:
- Open GPX Tracker (iOS, free, no account) is the one I use. It does one thing, it logs continuously, and it hands you a plain GPX file you can share straight into Roadbook '71. There is no cloud round-trip and nothing to sign into.
- A bike computer or GPS unit (Garmin, Wahoo, a handheld) records at a steady interval with a better antenna than a phone and does not care about incoming calls. If you already carry one, use it.
- Strava or Komoot work fine, and most people already have one. Record the drive as an activity, then export the GPX (in Strava: the activity's ⋯ menu → Export GPX). Be aware that both apply some smoothing, and that Strava's privacy zones will clip the ends of the file, which matters here, because on a loop the ends are the join.
- A route you drew on a map site is legitimate too, and produces very clean diagrams, but it is a plan rather than a record. It cannot tell you the lane was closed or the surface was gravel.
Interval: one second, or as close as you can get
Set the logging interval to one second, or to the shortest the app offers. This is the single setting that matters most.
The reason is not accuracy in the usual sense. It is that a tulip is drawn from eighty-five metres of road either side of the junction. At 50 km/h that window is about twelve seconds. Recording once a second gives you roughly twenty-four points to draw the corner with, which is plenty. Recording once every five seconds gives you five, and five points make a polygon rather than a curve, so the hairpin comes out looking like a right angle.
The file cost is negligible: a 150 km drive at one-second intervals is a few hundred kilobytes.
Some apps offer "smart" or distance-based recording, which drops points on straights to save space. That is exactly backwards for this purpose: the straights are where you can afford to lose points and the corners are where you cannot, and a distance-based sampler cannot tell the difference. Use a fixed time interval if you are given the choice.
Where to put the phone
Somewhere it can see the sky, and somewhere it will stay put.
On the dashboard or clipped to a vent is good. In a jacket pocket is usually fine. In the glovebox, in a metal-lidded cubby, or under a bag on the passenger footwell is where recordings go to die. You get a track that wanders twenty metres to one side of the road for ten kilometres and then snaps back.
Two practical notes for open cars: a phone on the dashboard in direct sun will thermally throttle and, eventually, shut down, taking the recording with it. And a phone that is not clamped will end up in the footwell on the first proper corner. Both of those have happened to me.
Keep it plugged in. Continuous GNSS logging is one of the more expensive things a phone can do, and a four-hour drive will take a serious bite out of a battery that started at 80%.
What to do before you set off
- Start recording while stationary, and give it thirty seconds. The first fixes after a cold start are the worst ones in the whole file. Thirty seconds parked at the kerb means the drive begins with a settled position rather than a fifty-metre jump.
- If you are recording a loop, finish where you started. Drive back past the point you set off from before you stop the recording. A ring that is closed to within a few metres is unambiguously a loop; one that stops eight hundred metres short leaves the app to guess whether you meant a ring or a line.
- Do not pause. A paused-and-resumed recording produces a straight-line jump across whatever happened in between, which is indistinguishable, in the file, from a lost signal.
What goes wrong, and what it looks like
Two failures are common enough to be worth recognising.
A dropout
The track runs along the road, then jumps in a dead straight line to a point a kilometre or two away, then carries on normally. That is a lost signal: a tunnel, a deep valley, a town with tall buildings, or the phone briefly deciding it had better things to do. Nothing was logged in between, so the file draws the shortest line between the last fix and the next one.
Roadbook '71 recognises these. Rather than sending you across a field, it asks the road network for a route across the gap and marks the result as a guess: the instructions along it are real, but whether the original drive actually went that way is not something the file can say. It is drawn thin and dashed, distinctly from a stretch where guidance goes quiet, because they are different problems.
A spike
A single point flung a few hundred metres sideways and back again, usually near a building or under trees. One bad fix. These are more annoying than dropouts because they are small enough to survive smoothing and large enough to distort a diagram: a spike inside the eighty-five-metre window around a junction will pull the tulip's fit out of shape.
The app measures the approach heading over thirty metres rather than over the first pair of points specifically so that one bad fix at the edge of the window cannot tip the whole diagram on its side. That handles the common case. A spike sitting right on the corner is harder, and the honest answer is that the diagram will look slightly wrong.
Two habits worth having
Open the file when you get home. Any GPX viewer will do. Look for straight lines that cut across country, which are your dropouts, and for the track leaving the road anywhere. Two minutes of looking tells you whether the recording is worth keeping.
Name it something you will recognise. The GPX has a name field, and it is what shows up in the app's library and at the top of the roadbook page. "Ourthe Circuit · Ortho & Bande" is a better thing to find in six months than "Track_2026-04-02_0912".
If you want to see what a good file looks like before recording your own, the sample loop is a real 45.7 km ring in the Ardennes, recorded at one-second intervals, and the roadbook printed from it shows what that file turns into.