How the numbers are calculated

Distance

The distance is the sum of the segments between consecutive points. When a file has several segments — a GPS signal lost in a tunnel, for example — the gap between them is counted too, as a straight line, so the total matches what you walked.

Climb and descent

A GPS altitude jitters by several meters from one point to the next. Added up naively, this noise turns a flat walk into hundreds of meters of climb. GPX Atlas therefore smooths the altitude and ignores changes under 3 m, which are mostly noise.

• Smoothing — off, light (the default) or strong — is set in Settings › Tracks. Stronger smoothing gives a lower, steadier climb.
• Routes drawn or planned are never smoothed: their points are far apart, and smoothing would flatten real climbs.
• While recording, the climb is read on every precise GPS fix, or on the phone's pressure sensor when barometric altitude is on, with the same threshold.
• Terrain elevation (see Routes, editing, export) replaces doubtful GPS altitudes with those of a terrain model.

That is why two apps rarely agree on the climb of the same file: each filters the noise its own way, and some replace the altitudes with a terrain model without saying so. Neither is wrong; compare like with like.

Time, speed and pace

Speed and pace use the times recorded in the file. Moving time leaves out the moments slower than 0.5 m/s (1.8 km/h), so breaks don't lower your average; the threshold can be set to 0.3, 0.5 or 1 m/s in Settings › Tracks. A track without times — a planned route, a track drawn on a website — shows distance and climb only.

A signal gap is a pause much longer than the usual interval between the points of the file: a track recorded every 30 seconds or more is not taken for a string of gaps, and keeps its whole moving time.

On the ground, the arrival time follows your speed over the last ten minutes; before that, it estimates from the distance and the climb left.

Splits, slope and sensors

• Splits are sized to the track: every kilometer or mile up to 25, then every 5, 10, 25 or 50, with the climb (or the descent), the time and the pace of each; the first ten are shown, then Show all. They can also be cut every 100 m of climb (300 ft when altitudes are in feet), each showing the distance it took.
• Slope is shown in percent or, if you prefer, in degrees (Settings › Units and formats).
• Heart rate, cadence, power and temperature are read from the file when it has them: averages, maximums and charts. Power also gives the normalized power, over 30-second windows.

Slope colors and climbs

Colored by slope, the track and the elevation profile use seven fixed classes, the same on every track: blue going down, gray-green on the flat, yellow to red going up, from under −15 % to over 15 %. A color always means the same slope.

A climb has at least 30 m of gain at 3 % on average; a dip of less than a fifth of what was climbed does not split it, and a flat stretch before the foot is left out. Climbs are numbered under the profile and listed in the sheet with their length, gain, average and steepest 100 m. Touch one to frame it on the map; pinch the profile to zoom, and the section shown is highlighted on the map.

Units

Units follow your phone's country: metric, imperial, or nautical (nautical miles and knots, altitudes in meters). In Settings › Units and formats, choose them freely, and speed, altitude and temperature separately.