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What is the calculation for longitude?

I recently have been doing a calculation for a new GPS system but can not crack Longitudes decreasing properties as Latitude Increases...

Basically as Latitude increases to 90 Longitude is 0 and as it hits 0 Longitude hits 100%..

Any conclusions? I am stuck and need help so anything will help stimulate the thought...

Latitude is working... Longitude is not so much...
HERE IS THE NEWEST LINKS:

https://docs.google.com/spreadsheet/ccc?key=0AgX5y-75MtwCdEgwZUlXQUZKVGhVQklLajg2T1FTcHc

http://www.gorissen.info/Pierre/maps/googleMapLocation.php

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  • Oct 1 2012: You can calculate longitude based on the meridian the same way you calculate lattitude based on the equator. Can you explain what you use to find the distance between the meridian and equator and the point you want to know the lattitude and longitude of? Does Google Maps provide a distance in km, or does it use its own coordinate system, have you compensated for the distortion resulting from representing our spherical planet as a flat surface?
    • Oct 1 2012: If I could use both the same calculation how would I determine sign change and the fact that it is a circle...

      The prime meridan Idea Is not going to work on this end because we are wanting a non specific calculation system that while be defined by the observer not pre diagnosed regulations...

      Google I have no clue but I am returning Excellent Latitudes but Longitude Is all over the map If I can pin down why then I can solve it but I first have to Iron out my logic...

      I JUST DON:T KNOW YET...
      • Oct 1 2012: "If I could use both the same calculation how would I determine sign change and the fact that it is a circle..."

        It should be exactly the same for longitude and lattitude, just rotated 90 degrees (if you rotate clockwise north becomes aest and south becomes west). You need trig functions for the actual math but you probably know that laready since you got the lattitude function working.
        • Oct 2 2012: That is what I thought but figuring out Latitude was the easy part but the algorithm for Longitude is proving a task. Not as simple as one would think...

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