Editing 426: Geohashing
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| − | == Explanation == | + | ==Explanation== |
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{{w|Geocaching}} is a sport where you have to find things hidden by other people based on geographical coordinates. Randall has had a similar idea before in [[201: Christmas GPS]]. | {{w|Geocaching}} is a sport where you have to find things hidden by other people based on geographical coordinates. Randall has had a similar idea before in [[201: Christmas GPS]]. | ||
| − | [ | + | [http://wiki.xkcd.com/geohashing/ Geohashing] is a sport created by Randall based on reaching a random location determined by an [http://wiki.xkcd.com/geohashing/Algorithm algorithm] that uses a {{w|hash function}} that involves the current date, location, and the {{w|Dow Jones Industrial Average|Dow}} opening price. The Dow Jones Industrial Average is a {{w|stock market index}} dealt in New York City. |
The algorithm is built in a way that: | The algorithm is built in a way that: | ||
| − | * Makes it impossible to plan a meeting in advance | + | *Makes it impossible to plan a meeting in advance - because of the Dow. |
| − | + | *Changes every day. | |
| − | * Changes every day | + | *Gathers people who are nearby - everyone within the same 1°×1° grid square gets the same position. |
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| − | * Gathers people who are nearby - everyone within the same 1°×1° grid square | ||
The algorithm works as follows: | The algorithm works as follows: | ||
| − | # Take the current date in the format yyyy-mm-dd and append the most recent opening value for the Dow Jones Industrial Average. | + | # Take the current date in the format yyyy-mm-dd- and append the most recent opening value for the Dow Jones Industrial Average. |
# Pass this string through the MD5 algorithm. | # Pass this string through the MD5 algorithm. | ||
# Divide the hash value into two 16 character halves, and convert each half to a decimal. | # Divide the hash value into two 16 character halves, and convert each half to a decimal. | ||
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{{w|MD5}} is a cryptographic hashing algorithm, and converts plaintext data into a seemingly random 128-bit (32 character) string. A good hashing algorithm should have three main properties: it is non-reversible, you cannot generate any plaintext data back from the hash, and a given sample of data will always produce the same hash value, but even a tiny change to the original plaintext should produce an entirely different hash. | {{w|MD5}} is a cryptographic hashing algorithm, and converts plaintext data into a seemingly random 128-bit (32 character) string. A good hashing algorithm should have three main properties: it is non-reversible, you cannot generate any plaintext data back from the hash, and a given sample of data will always produce the same hash value, but even a tiny change to the original plaintext should produce an entirely different hash. | ||
| − | The example co-ordinates are for the Google headquarters in California, as you can see here: [https://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=37.421542+-122.085589&aq=&sll=37.0625,-95.677068&sspn=73.209607,135.263672&vpsrc=0&ie=UTF8&t=m&z=17&iwloc=A 37.421542 -122.085589]. The example date, May 26 2005, may reference the fact that the first edition of the Dow came out on May 26 | + | The example co-ordinates are for the Google headquarters in California, as you can see here: [https://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=37.421542+-122.085589&aq=&sll=37.0625,-95.677068&sspn=73.209607,135.263672&vpsrc=0&ie=UTF8&t=m&z=17&iwloc=A 37.421542 -122.085589]. The example date, May 26 2005, may reference the fact that the first edition of the Dow came out on May 26. |
| − | While geohashing was originally intended as a joke, | + | While geohashing was originally intended as a joke, there are people who geohash regularly. Please see the link to the xkcd wiki above. |
| − | The title | + | The title text may imply that people should bring games to their geohashing location on the Saturday following the comic's release. |
==Transcript== | ==Transcript== | ||
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[[Category:Comics with color]] | [[Category:Comics with color]] | ||
[[Category:Stock Market]] | [[Category:Stock Market]] | ||
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