Activity Calculations
Activity calculation settings control the distance, ascent, descent, and estimated time shown for your Routes and Tracks. Open Settings > Activities, choose an Activity such as Walking, then open Planning & statistics.
Walking Defaults
Walking starts with these values. Your account may have different values if you have changed them.
| Setting | Built-In Walking Value |
|---|---|
| Elevation algorithm | Average |
| Tracklog distance filtering | 5 metre threshold |
| Speed | 5 km/h |
| Ascent | 600 metres/hour |
| Descent | 600 metres/hour |
Speed and height rates are displayed in your chosen units. The threshold choices are labelled in metres.
Average elevation and the 5 metre threshold distance filter are OMN4's built-in starting values for walking. The elevation choices let you decide how much of the terrain's smaller rises and falls contributes to your totals.
Elevation Algorithm
The elevation algorithm controls how OMN4 adds up ascent and descent from its terrain height data. It applies to both Routes and Tracks. It does not change the recorded GPS positions or the height of the terrain.
Imagine two contour lines on an OS map, 10 m apart vertically and 100 m apart horizontally. Counting the climb from one contour to the next gives 10 m of ascent. Within that 100 m, however, the ground might rise and fall by 3–4 m several times. Terrain height data can capture some of those undulations, giving a higher total ascent even though the overall height difference is still 10 m.
The elevation choices let you include more of that smaller-scale detail or concentrate on the larger rises and falls. Choose the level of detail you are comfortable looking at and comparing across your walks. A different total does not by itself mean one calculation is right and another is wrong.
| Choice | What It Does |
|---|---|
| Average | Adds the rises and falls in OMN4's smoothed terrain height samples, with no additional vertical threshold. |
| 1 metre threshold, 2 metre threshold, 3 metre threshold | Counts a change once the height differs from the last accepted height by at least the selected amount. Retains smaller undulations than the larger thresholds. |
| 5 metre threshold, 10 metre threshold, 15 metre threshold | Uses the same rule with a larger vertical change, leaving more of the smaller rises and falls out of the totals. |
For example, with a 5 metre threshold, suppose the sampled heights are 100 m, 102 m, 104 m, then 106 m. The first two rises do not yet count. At 106 m, OMN4 counts the full 6 m of ascent and uses 106 m as the new reference height. It does not subtract 5 m from the climb. A subsequent fall to 103 m does not yet count as descent; a fall to 101 m counts 5 m.
The reference carries on across the points in a continuous Route or Track. A final change smaller than the threshold can remain uncounted. The threshold is a vertical height difference, not a minimum gradient or a distance between recorded points.
Average includes the rises and falls present in OMN4's smoothed height samples. A threshold gives less emphasis to smaller undulations. Compare the choices on a familiar walk, then use the same setting when comparing your walks so the totals have a consistent basis.
When comparing OMN4 with contour counting or another mapping product, allow for differences in both the height data and the calculation method. A 10 metre threshold does not reproduce counting 10 m contours: its reference moves whenever a height change is accepted, rather than following the map's fixed contour levels. Height data also has a limited resolution, so it cannot capture every rise and fall on the ground.
Tracklog Distance Filtering
GPS positions can wander when you are standing still or moving slowly. Tracklog distance filtering reduces how much those small apparent movements add to a Track's distance. It applies to Tracks, including imported Tracks; it does not filter a planned Route's distance.
| Choice | What It Does |
|---|---|
| Unfiltered | Adds the distances between consecutive recorded points within each continuous segment. |
| 3 metre threshold | Uses a 3 m minimum movement before adding distance. |
| 5 metre threshold | Uses a 5 m minimum movement; the built-in Walking value. |
| 7 metre threshold | Uses a 7 m minimum movement, suppressing more small movements. |
With a threshold selected, OMN4 measures from the last position accepted for the distance calculation. Points closer than the threshold do not add distance yet. When a point reaches the threshold, OMN4 adds the whole straight-line distance from that reference position and moves the reference to the new point.
For example, on a straight line with a 5 m threshold, a point 4 m from the reference adds nothing yet. A later point 8 m from the reference adds 8 m. OMN4 does not simply discard every short step between neighbouring points.
If a point includes GPS accuracy information, OMN4 uses the larger of that accuracy value and the selected threshold. With 10 m reported accuracy, a 5 m filter therefore waits for at least 10 m of movement from the reference. An imported Track without accuracy information uses the selected threshold alone.
Start with 5 metre threshold for walking. A smaller threshold retains more small movements but can include more GPS wander. A larger threshold can reduce wander, but may shorten tight bends and small genuine movements. Unfiltered is useful for comparison and may show extra distance from GPS wander.
Filtering changes calculated distance, including the distance shown while recording. It does not delete points, change the drawn Track, or change recording frequency. OMN4 restarts the distance reference at a tracklog segment break so movement across a pause is not added.
The filter belongs to the Track's Activity. Change it under Settings > Activities; it is not a global control under Tracklogs. Existing Tracks using that Activity also use its filter.
Estimated Time And Naismith-Style Settings
OMN4 calculates estimated time by adding three allowances:
- Distance divided by Speed.
- Ascent divided by the Ascent rate, when that rate is greater than zero.
- Descent divided by the Descent rate, when that rate is greater than zero.
A higher ascent or descent rate means less time added for the same height change. Setting a height rate to zero adds no time for that part of the calculation. Speed must be greater than zero to calculate an estimate.
There is no separate Naismith switch. For a distance-plus-ascent, Naismith-style estimate, use Speed: 5 km/h, Ascent: 600 metres/hour, and Descent: 0. That gives 3 hours for 10 km with 600 m of ascent. The built-in Walking settings also add a descent allowance: with 600 m of descent as well, the built-in values give 4 hours.
The selected elevation algorithm supplies the ascent and descent totals used in this estimate, so changing it can also change the estimated time. Tracks use their Activity's distance filter when calculating estimated time. Recorded elapsed and moving times come from track timestamps instead.
Choose Walking as your Default Activity to use it for newly created Routes. To change an existing Route, choose its Activity in Properties. Changing Walking's calculation settings affects items that use Walking; it does not assign Walking to items using another Activity. See Activities.
Estimated time is a planning aid. Add your own allowance for stops, conditions, terrain, and your pace.