Time-traveller achievement
From Geohashing
Revision as of 15:29, 26 April 2016 by imported>Mckaysalisbury (Add clarification about time zones, and explicitly mention international date line.)
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This user earned the Time-traveller achievement
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The achievement can be claimed if you venture to two or more geohashing locations on the same day and the same local time.
If you don't own a time-machine, you could ...
- cross a time-zone border, and go fast.
- In most cases, time zone borders are separated by an hour which gives you one hour to travel the 69 miles (times the cosine of the latitude) necessary, which can be difficult.
- This gives geohashers further from the equator a slightly easier task, as the distance between graticules is smaller at higher latitudes.
- Across the international date line is a time zone border of usually around 24 hours. This should give substantial time to cross to the next graticule, but most of these are on water.
- There are places where the time zone borders are more than an hour apart, while this is makes it much easier, there are usually (but not always, e.g. Russia, Australia) international boundaries to travel through, which can also take additional time).
- In most cases, time zone borders are separated by an hour which gives you one hour to travel the 69 miles (times the cosine of the latitude) necessary, which can be difficult.
- take advantage of the autumn daylight saving clocks change, and go fast.
- Just like the time zone borders, higher latitudes make the journey shorter.
- be in a mirror graticule and get extremely lucky.
- Because graticules that touch across the equator or the prime meridian or the 180° meridian mirror each other, there is a very small chance, if you're standing on the border between them, that you could be in the circle of uncertainty for two hashpoints simultaneously.
- For those graticules that touch across the equator, this happens if the latitude of the hashpoint is less than 0.000036°.
- For those that touch across the prime or 180° meridian, the required longitude of the hashpoint can be calculated from the expression 0.000036° / cos(latitude).
- Note that across the 180° Meridian, they points only mirror each other on the weekend, because of the 30°W rule.
- Because graticules that touch across the equator or the prime meridian or the 180° meridian mirror each other, there is a very small chance, if you're standing on the border between them, that you could be in the circle of uncertainty for two hashpoints simultaneously.
- Go near the poles and be lucky.
- At latitudes 89°N or 89°S, because graticules get narrower east-west the further north they are, hashpoints at all longitudes are closer to each other. When the latitude of the hashpoint is greater than 89.9984° the circles of uncertainty for two hashpoints will overlap.
- Get very very extremely lucky because of the 30°W rule.
- On weekdays hashpoints east and west of longitude 30°W are calculated separately, so may both be close to 30°W or 180°E/W. However, pretty much all of these points will be in an ocean.
Of course, as usual, you need to upload photos of yourself containing the necessary proof.
Winners
- Woodveil was at the 2009-03-08 33 -84 and 2009-03-08 33 -85 hashes at 12:39 local time.
- B2c and Patrizius were at the 2013-10-27 47 13 and 2013-10-27 47 12 hashes at 02:09 local time. It was a DST time travel.
- Micsnare and B2c were at the 2014-10-26 47 14 and 2014-10-26 47 13 hashes at 02:01 local time. It was a DST time travel. Again ;)
See also
Multihash -- reach multiple geohashes on one day
