Three word location: Difference between revisions

=={{header|Julia}}==

Direct translation from the SymSyn example given by the task creator. though note that idiomatic Julia would usually code this as two small encode() and decode() functions.

<lang julia>

# Three Word Location - convert latitude and longitude to three words

LAT = 28.3852

LON = -81.5638

# build word array W00000 ... W28125

wordarray = ["W" * string(x, pad=5) for x in 0:28125]

# make latitude and longitude positive integers

ILAT = Int(LAT * 10000 + 900000)

ILON = Int(LON * 10000 + 1800000)

# build 43 bit integer containing latitude (21 bits) and longitude (22 bits)

LATLON = (ILAT << 22) + ILON

# isolate most significant 15 bits for word 1 index

# next 14 bits for word 2 index

# next 14 bits for word 3 index

W1 = (LATLON >> 28) & 0xefff

W2 = (LATLON >> 14) & 0x7fff

W3 = LATLON & 0x7fff

# fetch each word from word array

w1 = wordarray[W1 + 1]

w2 = wordarray[W2 + 1]

w3 = wordarray[W3 + 1]

# display words

println("$w1 $w2 $w3")

# reverse the procedure

# look up each word

(w1index, w2index, w3index) = indexin([w1, w2, w3], wordarray) .- 1

# build the latlon integer from the word indexes

latlon = (w1index << 28) | (w2index << 14) | w3index

# isolate the latitude and longitude

ilon = latlon & 0xfffff

ilat = latlon >> 22

# convert back to floating point values

lon = (ilon - 1800000) / 10000

lat = (ilat - 900000) / 10000

# display values

println("latitude = $lat longitude = $lon")

</lang>{{out}}

<pre>

W18497 W27708 W01322

latitude = 28.3852 longitude = -81.5638

</pre>