StepLength Pro

StepLength Pro measures your step length — and tells you how far off that number might be. It is not a step counter. What it measures is the length of each step. Once you have a measured baseline, you can work out distance from your step count alone, with no map and no GPS. ■ Not just a number, but how much you can trust it Step length is distance divided by steps. Anyone can do that division. What this app gives you looks like this: 74.2 cm ± 1.6 cm (quality: High) "74.2 cm ± 1.6 cm" and "74.2 cm ± 5.0 cm" mean very different things. A number with its uncertainty hidden cannot tell you whether it is right or just lucky, so this app always shows the ±. Quality is rated High / Med / Low, and the app tells you why it got that rating. ■ Three ways to measure [Known distance] Walk a distance you already know — a running track, a corridor, a straight road — and the app counts only your steps. No GPS, works indoors, most accurate. [GPS straight line] Walk a straight line outdoors. You hold still for 10 seconds at the start and at the end while the app averages its position fixes, then it uses the distance between those two points. [Pace estimate] Uses your baseline step length to work out distance from your step count. No GPS. Find out how long that path is just by walking it. ■ No GPS route integration Many apps add up the distances between GPS points. Because positioning noise always makes that path longer, the result comes out several percent to over ten percent too long. StepLength Pro uses only the straight-line distance between the start and end points. Errors do not pile up, so the longer you walk, the smaller the relative uncertainty. ■ A baseline for each condition Your step length changes with speed and footwear. Keep separate profiles — Normal walk, Slow, Brisk — each with its own baseline. Add, rename and reorder them freely. The baseline is an inverse-variance weighted mean, not a simple average, so more precise measurements automatically count for more and a poor measurement cannot drag it off. Clear outliers are excluded automatically and marked in the list. ■ Also ・Voice and vibration cues, so you can measure without looking at the screen ・Keeps measuring with the phone in your pocket and the screen off ・Scatter plot of cadence (steps/min) against step length, with a regression line ・Export your history as CSV ・Switch between step length and stride, and between m / cm / ft-in ・Choose the StepLength Pro colours or match your device ■ Tips for good results ・Walk 100 m or more. Below 50 m the quality is rated Low ・Measuring over a known distance is the most accurate ・In GPS straight-line mode, walk straight. A curved route is not a measurement ■ Your data Measurement data — step counts, distances and GPS coordinates — is stored only on your device. The app never sends it anywhere, location included. This app contains banner ads (Google AdMob). The ad SDK collects information such as the advertising ID to serve ads. See the privacy policy for details. No ads are shown while measuring, so you will not tap one by accident when you take out your phone to finish. ■ Requirements A device with a step sensor (TYPE_STEP_DETECTOR / TYPE_STEP_COUNTER) is required. Measurement is not possible on devices without one. Some power-saving settings can stop the sensor while the screen is off. If measurements get cut off, exclude this app from battery optimisation.