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Can someone explain how can get the Lat/Lon of a given Grid square? (the middle of the grid would be the best). I've looked at this (that does the "reverse"...from lat/lo to grid"):

How can one convert from Lat/Long to Grid Square?

But i need to do the inverse...

Anyone can explain in step by step?

Many thanks!

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Michele MichelinoK Costantino
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3 Answers3

3

if by "Grid" you mean "Maidenhead Locator" then here is a similar question, with some sample Python code as answer.

The result from the code will be

Lon = (start_lon) to (end_lon)
Lat = (start_lat) to (end_lat)

From that you can easily calculate the "middle" of the square. or you can take the code and adapt, here is the code from the above mentioned question/answer:

# -*- coding: utf-8 -*-
#maiden head to lon/lat

__MH__ = 'HK34wh'

def GetLon(ONE, THREE, FIVE):
    StrStartLon = ''
    StrEndLon = ''

    Field = ((ord(ONE.lower()) - 97) * 20) 
    Square = int(THREE) * 2
    SubSquareLow = (ord(FIVE.lower()) - 97) * (2/24)
    SubSquareHigh = SubSquareLow + (2/24)

    StrStartLon = str(Field + Square + SubSquareLow - 180 )
    StrEndLon = str(Field + Square + SubSquareHigh - 180 )

    return StrStartLon, StrEndLon

def GetLat(TWO, FOUR, SIX):
    StrStartLat = ''
    StrEndLat = ''

    Field = ((ord(TWO.lower()) - 97) * 10) 
    Square = int(FOUR)
    SubSquareLow = (ord(SIX.lower()) - 97) * (1/24)
    SubSquareHigh = SubSquareLow + (1/24)

    StrStartLat = str(Field + Square + SubSquareLow - 90)
    StrEndLat = str(Field + Square + SubSquareHigh - 90)    

    return StrStartLat, StrEndLat

def main(strMaidenHead = __MH__):
    if len(strMaidenHead) < 6: strMaidenHead = __MH__

    ONE = strMaidenHead[0:1]
    TWO = strMaidenHead[1:2]
    THREE = strMaidenHead[2:3]
    FOUR = strMaidenHead[3:4]
    FIVE = strMaidenHead[4:5]
    SIX = strMaidenHead[5:6]

    (strStartLon, strEndLon) = GetLon(ONE, THREE, FIVE)
    (strStartLat, strEndLat) = GetLat(TWO, FOUR, SIX)

    print ('Start Lon = ' + strStartLon)
    print ('End   Lon = ' + strEndLon)
    print ()
    print ('Start Lat = ' + strStartLat)
    print ('End   Lat = ' + strEndLat)

    return strStartLon, strEndLon, strStartLat, strEndLat

#BEGIN
if __name__ == '__main__':
    main ()
    sys.exit ('end of script: '+ os.path.basename(__file__) + os.linesep + 'by: Edwin van Mierlo')
#END

(for the purists amongst you, no; this is not very 'pythonic', but it does work)

Community
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Edwin van Mierlo
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1

There is a Python package converting to/from Maidenhead/WGS84 Lat/Lon

scivision
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1

I've created many (two, PHP is going up shortly) implementations of this on my github page. Please feel free to use these: https://github.com/gravypod/maidenhead/

I'm also very happy to take pulls in to either add more implementations or clean up my implementations. It would be nice to get a version for every manjor language out there. I just haven't got the time to do that sadly.

I've also found it hard to convert from Lat Lon to maidenhead which would be very nice to have.

Joshua Katz
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