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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

• #### Joshua Sisk

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Oct 1 2012: Not homework!!!! This has been a project that I have been working on for a few months now will let someone continue the work if I knew they would not scrap the Idea... Fritzie can back me up on that one...
• #### Fritzie -

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Oct 1 2012: I can verify, Dan, that this is not Joshua's homework but rather one of his projects.
Still, this calculation is algorithmic, and I think the best advice would come from the same sort of site that helps people with homework in this area.
• #### John Smith

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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?
• #### Joshua Sisk

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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...
• #### John Smith

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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.
• #### Joshua Sisk

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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...
• #### Mark Kurtz

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Sep 30 2012: I am not visualizing your problem. Longitude increases going west of the prime meridian or east of the prime and is stated E or W. Latitude increases moving away from the equator and is stated N or S. Very simple really. So, how does a GPS use this information differently?
• #### Joshua Sisk

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Sep 30 2012: GOOD now visualize what the equation is facing...

Latitude and longitude are the restrictions to times equation but longitude is restricted by times calculation literally....

I can calculate latitude from the equator because it is a simple distance from 0, so observer is how far from 0?

Now how do I ask the same question for longitude in math equivalant terms?

The steps of the excel are

AVERAGING
CIRCUMFERENCE
PYTHAGOREAN THEOREM (Latitudinal step of calculation...)
• #### Fritzie -

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Oct 1 2012: Have you done an internet search for the algorithm so that you don't need to "reinvent the wheel?"

For example, if you do an internet search for formula for longitude, Pearson has a formula sheet you can download, doesn't it, and steps using Excel?

And here is a link to a group of tutors who answer questions like yours online:
http://www.transtutors.com/homework-help/earth-science/geophysics/longitude/
• #### Joshua Sisk

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Oct 1 2012: Actually, I would like to say sorry for not keeping track of this post but I know what is happening with longitude but I can't explain why thing are working the way they are...

Since longitude handles four hemispheres it required two sign changes one for Southeast Northwest and NORTHEAST or SOUTHWEST...

But I had latitude at a right angle from the equator to the axis of the observer latitude then from the axis the longitude spreads out to form a new diameter at the observed latitude.

Again I not sure if I have the calculations right but the process of what is happening is locked down...

Select FILE/DOWNLOAD AS
https://docs.google.com/spreadsheet/ccc?key=0AgX5y-75MtwCdDJDZjhVM1pZUmZZelM0OUE0emdsR0E

The first green is latitude the the other Items stacked are Longitude

To use with open office you must first rename and save document...

Here are the two videos that tested the equation...
http://www.youtube.com/watch?v=ARhTMMjzVtg

http://www.youtube.com/watch?v=fIcZv55wF2Y

I do thank everyone in the videos they do not plea for money at this point but I do need help testing the equation so If others could test it out and then tell me what is happening I will not beable to do extensive testing for a week and a half...

The circle has a left and right and can be above or below the equator... This handles the equations needed to calculate Longitude... Since Latitude is always positive because Pythagorean Theorem is required to calculate; I know I am correct in my thought process it is now Ironing out the equations needed.
• #### Joshua Sisk

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Oct 1 2012: The wheel has yet to be created we know what it is with quadrants or four quarters of a circle but to navigate a variety of circles without restraints or errors is the true mastery we must find.

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• #### Joshua Sisk

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Sep 30 2012: Totally correct... I can get half the world right it is the other half that Is off The equations signs are mixed up I will think about this... Thank you so much...
• #### Joshua Sisk

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Oct 2 2012: Quite alright if this is deemed inappropriate was just trying to get some new mental juice in the equation...
• #### Joshua Sisk

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Sep 30 2012: If I turn the time of day into the prime meridian then I can figure out what degree of change the observer is from that point in time...

KEEP THE STIMULATION OF ANSWERS COMING WE WILL CRACK THIS BEFORE THE END OF THE REstricted time...