Long journeys
From OpenStreetMap
This page is about how to record a long journey for OpenStreetMap, in situations where you may not have access to computers for several days at a time.
The GPS then needs to record your entire journey in its internal memory, rather than downloading it to a computer daily like we do for shorter trips.
Contents |
Which GPS
In the event that you're considering a new GPS specially for the journey, have a look at GPS reviews or ask on the mailing lists.
Considerations might include:
- Size - Geko 201 is much much smaller than "standard" handheld GPS's
- Tracklog memory - handheld units store only 10000 points, which you can stretch out to cover a few days' journey if you accept lower resolution. Some come with flash card memory which is ideal, but they tend to be the "logging only" units. Notable exceptions here are the 'x' units from Garmin, eg, the Etrex Legend Cx, which is a handheld unit with integrated mapping screen, and replaceable flash card memory. PDAs with built-in or external GPS also usually have the abiliti to use SD cars or simmilar.
- Usefulness for walking - the "logging only" GPS units may be good for recording your journey, but they're not as fun to use and you can't see where you are, navigate to pubs with them, or use them to navigate off the hill in an emergency.
Tracklog mode
Many GPS units have an adjustable formula for saying when they log each point. Options tend to include
- Auto (about every 100 metres, or closer when turning a corner)
- By distance
- By time
Distance intervals
Distance intervals are quite "reliable", as they give the same density of tracks no matter how fast you're going. (be careful in cities where streets might be closer together than that distance interval)
| Interval | Distance that can be logged |
|---|---|
| metres | miles |
| 5 | 31 |
| 10 | 62 |
| 15 | 93 |
| 20 | 124 |
| 25 | 155 |
| 30 | 186 |
| 40 | 248 |
| 50 | 311 |
| 60 | 373 |
| 70 | 435 |
| 80 | 497 |
| 90 | 559 |
| 100 | 621 |
Journey length that can be covered using a 10000-point tracklog, by setting the logging interval to various distances
Time intervals
Time intervals are good for seeing how fast you were going (footpaths appear as dense lines, motorways appear as sparse lines), and it makes it easy to see traffic lights, cafes, and other places where you've stopped. Remember to turn the GPS off when you have lunch, otherwise it'll record hundreds of points there!
| Interval | Logging time | 6-hour days | distance walked | distance cycled |
|---|---|---|---|---|
| seconds | hours | miles | miles | |
| 1 | 3 | 0 | 11 | 33 |
| 2 | 6 | 1 | 22 | 67 |
| 3 | 8 | 1 | 33 | 100 |
| 4 | 11 | 2 | 44 | 133 |
| 5 | 14 | 2 | 56 | 167 |
| 6 | 17 | 3 | 67 | 200 |
| 7 | 19 | 3 | 78 | 233 |
| 8 | 22 | 4 | 89 | 267 |
| 9 | 25 | 4 | 100 | 300 |
| 10 | 28 | 5 | 111 | 333 |
| 12 | 33 | 6 | 133 | 400 |
| 14 | 39 | 6 | 156 | 467 |
| 16 | 44 | 7 | 178 | 533 |
| 18 | 50 | 8 | 200 | 600 |
| 20 | 56 | 9 | 222 | 667 |
| 22 | 61 | 10 | 244 | 733 |
| 24 | 67 | 11 | 267 | 800 |
| 26 | 72 | 12 | 289 | 867 |
| 28 | 78 | 13 | 311 | 933 |
| 30 | 83 | 14 | 333 | 1000 |
Journey length that can be covered using a 10000-point tracklog, by setting the logging interval to various time periods.
Third column shows how many days you can log at that interval. Last two columns show the approximate distance walking or cycling that those times represent (assuming average 4mph, 12mph respectively)
Battery-life considerations
- Check the battery life of a GPS device when purchasing; most last about 8 hours, not long enough for a long day. Some last for 10 hours which is much better, particularly if you switch it off when taking a rest break.
- Consider buying a GPS device that takes standard rechargeable batteries so that you can afford to buy plenty of spares. Many devices require you to buy manufacturer-specific spare battery in the region of US$50 more.
- If you are doing your trip by car, buy a cigarette-lighter charger.
