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en:help:1.4:landmarks:statistics [2014/11/02 21:48] – alpinequest | en:help:1.4:landmarks:statistics [2014/11/02 21:55] – alpinequest | ||
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===== Gain and loss ===== | ===== Gain and loss ===== | ||
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In order to compute these values, it's important to define more precisely what means "along the track" | In order to compute these values, it's important to define more precisely what means "along the track" | ||
- | A first definition would be to take into account **the altitude differences between mountain passes and summits**. If you start a hike at +150m, climb to a summit at +500m, then go back to your start location at +150m, your gain will be 350m. In practice, trails usually don't go straight forward to the summit, but will go uphill for some time, then downhill a little bit, then uphill again, etc. This first definition doesn' | + | A first definition would be to only take into account **the altitude differences between mountain passes and summits**. If you start a hike at +150m, climb to a summit at +500m, then go back to your start location at +150m, your gain will be 350m. In practice, trails usually don't go straight forward to the summit, but will go uphill for some time, then downhill a little bit, then uphill again, etc. This first definition doesn' |
Another definition would then be to take into account **the altitude differences between all the locations that make the track**. Now imagine a track recorded with a GPS along the sea. The GPS, having an imperfect accuracy, will record altitudes of [+1m, +2m, 0m, +1m, -1m, +2m, ...]. With this small segment of 6 locations, we have a gain of +5m. With a track of 1000 locations, it would lead to a gain of more than +800m which is a very **over-estimated gain**, since the track is along a flat shoreline and should have no gain. | Another definition would then be to take into account **the altitude differences between all the locations that make the track**. Now imagine a track recorded with a GPS along the sea. The GPS, having an imperfect accuracy, will record altitudes of [+1m, +2m, 0m, +1m, -1m, +2m, ...]. With this small segment of 6 locations, we have a gain of +5m. With a track of 1000 locations, it would lead to a gain of more than +800m which is a very **over-estimated gain**, since the track is along a flat shoreline and should have no gain. | ||
- | At then end, the " | + | At then end, the " |
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