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  1. #1
    Join Date
    May 2014

    reverse function


    I have code for conversion of longitude and latitude and I need help to reverse the function so it will work in opposite direction:

    float LongitudeDeg = argv[1]; // some longitude
    float LatitudeDeg = argv[2]; // some latitude
    uint32_t u,v,l,n;
    l=15; // l range is 2-29
    LongitudeData = int(0.5 + (180 + LongitudeDeg) * (0x2000000 / 15));
    LatitudeData = int(0.5 + (90 - LatitudeDeg) * (0x8000000 / 45));
    if ( LongitudeData > 0x30000000)
    	LongitudeData -= 0x30000000;
    if (LongitudeData < 0)
    	LongitudeData += 0x30000000
    if ( LatitudeData > 0x20000000 )
    	LatitudeData -= 0x20000000;
    if ( LatitudeData < 0 )
    	LatitudeData += 0x20000000);
    n = 30 - l;
    u = LongitudeData >> n;
    v = LatitudeData >> n;
    On start of the code we know longitude,latitude and l. And the result is u and v. And I need function when I will know the u and v, possibly l too, to calculate longitude, latitude.

    Can you help with it?

  2. #2
    VictorN's Avatar
    VictorN is offline Super Moderator Power Poster
    Join Date
    Jan 2003
    Hanover Germany

    Re: reverse function

    What are "physically" these LongitudeDeg, LatitudeDeg, LongitudeData, LatitudeData, l, u and v?
    Victor Nijegorodov

  3. #3
    Join Date
    Mar 2002
    St. Petersburg, Florida, USA

    Re: reverse function

    Basic algebra....not really a programming question....
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