Converting DMS DMM DD to latitude & longitude

parseDMS.coffee

    parseDMS = (dmsString) ->
      dmsString = dmsString.trim()

      dmsRe = /([NSEW])?(-)?(\d+(?:\.\d+)?)[°º:d\s]?\s?(?:(\d+(?:\.\d+)?)['’‘′:]\s?(?:(\d{1,2}(?:\.\d+)?)(?:"|″|’’|'')?)?)?\s?([NSEW])?/i
      result = {}
      m1 = undefined
      m2 = undefined
      decDeg1 = undefined
      decDeg2 = undefined
      dmsString2 = undefined

      m1 = dmsString.match(dmsRe)

      if !m1
        throw 'Could not parse string'

      if m1[1]
        m1[6] = undefined
        dmsString2 = dmsString.substr(m1[0].length - 1).trim()
      else
        dmsString2 = dmsString.substr(m1[0].length).trim()

      decDeg1 = decDegFromMatch(m1)
      m2 = dmsString2.match(dmsRe)
      decDeg2 = if m2 then decDegFromMatch(m2) else {}

      if typeof decDeg1.latLon == 'undefined'
        if !isNaN(decDeg1.decDeg) and isNaN(decDeg2.decDeg)
          return decDeg1.decDeg
        else if !isNaN(decDeg1.decDeg) and !isNaN(decDeg2.decDeg)
          decDeg1.latLon = 'latitude'
          decDeg2.latLon = 'longitude'
        else
          throw 'Could not parse string'

      if typeof decDeg2.latLon == 'undefined'
        decDeg2.latLon = if decDeg1.latLon == 'lat' then 'lon' else 'lat'

      result[decDeg1.latLon] = decDeg1.decDeg
      result[decDeg2.latLon] = decDeg2.decDeg

      result

    decDegFromMatch = (m) ->
      signIndex =
        '-': -1
        'N': 1
        'S': -1
        'E': 1
        'W': -1
      latLonIndex =
        'N': 'lat'
        'S': 'lat'
        'E': 'lon'
        'W': 'lon'
      degrees = undefined
      minutes = undefined
      seconds = undefined
      sign = undefined
      latLon = undefined
      sign = signIndex[m[2]] or signIndex[m[1]] or signIndex[m[6]] or 1
      degrees = Number(m[3])
      minutes = if m[4] then Number(m[4]) else 0
      seconds = if m[5] then Number(m[5]) else 0
      latLon = latLonIndex[m[1]] or latLonIndex[m[6]]
      if !inRange(degrees, 0, 180)
        throw 'Degrees out of range'
      if !inRange(minutes, 0, 60)
        throw 'Minutes out of range'
      if !inRange(seconds, 0, 60)
        throw 'Seconds out of range'
      {
        decDeg: sign * (degrees + minutes / 60 + seconds / 3600)
        latLon: latLon
      }

    inRange = (value, a, b) ->
      value >= a and value <= b