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| − | Note: This is an experimental proposal.
| + | #redirect[[centicule#Pinecone's algorithm]] |
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| − | A '''decicule''' is approximately one hundredth the area of a graticule, or more precisely the set of coordinates that has a common integer part and tenths digit for both the latitude and longitude. This follows the proposal set forth by [[User:Pinecone|Pinecone]].
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| − | A '''decihash''' of a decicule is the same as the geohash of the graticule of which it is a part, except differing in the tenths digit where it takes the tenth digit of the decicule. This follows [[User:Pinecone|Pinecone]]'s basic philosophy, but makes it simpler based on [[User:Rspeer|Rspeer]]'s comments.
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| − | ==Implementation==
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| − | <pre>
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| − | # decihash.py
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| − | # by Paradoxian, based on Python implementation 2 at:
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| − | # http://wiki.xkcd.com/geohashing/Implementations | |
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| − | import hashlib, datetime, struct, urllib, re, sys, math, webbrowser
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| − | myLat = 34.0
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| − | myLon = -118.3
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| − | args = sys.argv
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| − | if len(args) == 1:
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| − | args.append(myLat)
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| − | args.append(myLon)
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| − | args[1] = float(args[1])
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| − | args[2] = float(args[2])
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| − | deciculeN = math.modf(args[1] * 10)[1] / 10
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| − | deciculeE = math.modf(args[2] * 10)[1] / 10
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| − | # may print wrong sign if rounds to -0.0, but result will still be correct | |
| − | print "Decicule:", deciculeN, deciculeE
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| − | if args[2] < -30:
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| − | td30 = 0
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| − | else:
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| − | td30 = 1
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| − | if args[1] < 0:
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| − | south = -1
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| − | else:
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| − | south = 1
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| − | if args[2] < 0:
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| − | west = -1
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| − | else:
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| − | west = 1
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| − | date = datetime.date.today()
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| − | djia = urllib.urlopen((date - datetime.timedelta(td30)).strftime("http://irc.peeron.com/xkcd/map/data/%Y/%m/%d")).read()
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| − | if djia.find('404 Not Found') >= 0: sys.exit(sys.stderr.write("Dow Jones not available yet.\n"))
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| − | sum = hashlib.md5("%s-%s" % (date, djia)).digest()
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| − | north, east = [str( d * (abs(a) + (f-(math.floor(f*10)/10)) ) ) for d, f, a in zip((south, west),
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| − | [x/2.**64 for x in struct.unpack_from(">QQ", sum)], (deciculeN, deciculeE) )]
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| − | print "Decihash:", north, east
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| − | dest = 'http://maps.google.com/maps?f=q&hl=en&geocode=&q=' + north + '+' + east + '&ie=UTF8&ll=' + north + ',' + east + '&spn=0.918082,1,864929&z=9&iwloc=addr'
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| − | print "URL:", dest
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| − | webbrowser.open(dest)
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| − | </pre>
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