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## Need Help

Im working on a homework assignment, looking for the great distance formula can someone help me? i try it but got the wrong answer

// GeoLocation.java

public class GeoLocation
{
private double latitude;
private double longitude;

// Construct a GeoLocation given the latitude and longitude.
public GeoLocation(double latitude, double longitude)
{
//
this.latitude = latitude;
this.longitude = longitude;
}

// Return the great circle distance between this location and b.
public double distanceTo(GeoLocation b)
{
// TBD
GeoLocation a = this;
double a1 = Math.sin(Math.toRadians(b.latitude - this.latitude) / 2 ) * Math.sin(Math.toRadians(b.latitude - this.latitude) / 2) +
Math.sin(Math.toRadians(b.longitude - this.longitude) / 2 ) * Math.sin(Math.toRadians(b.longitude - this.longitude) / 2) *

return a1;
}

// Is this location the same as b?
public boolean equals(GeoLocation b)
{
// TBD
if(b==this)
return true;
if(b==null)
return false;
GeoLocation a = this;
GeoLocation c = this;
return (a.latitude == b.latitude) && (a.longitude == b.longitude) && (b.latitude == c.latitude) && (b.longitude == c.longitude);
}

// Return a String representation of this location.
public String toString()
{
// TBD
return " " + latitude + " " + longitude + " ";
}

// Test driver.
public static void main(String[] args)
{
GeoLocation a = new GeoLocation(48.87, -2.33);
GeoLocation b = new GeoLocation(37.8, 122.4);
GeoLocation c = new GeoLocation(37.8, 122.4);
System.out.println("Should print 48.87, -2.33: " + a);
System.out.println("Should print 5561.369177680733: " +
a.distanceTo(b));
System.out.println("Should print false: " + a.equals(b));
System.out.println("Should print true: " + b.equals(c));
}
}

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huh?

db

5. ## Re: Need Help

What is the correct equation for computing the great circle distance between two locations?
What does a negative degrees represent? -2.33

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## Re: Need Help

I dont remember how to do the great circle distance.
I think the equation is Math.acos(Math.sin(x1) * Math.sin(x2) + Math.cos(x1) * Math.cos(x2) * Math.cos(y1 - y2));. Not sure if I am writing it right or not in my code. I'm not sure what you mean by negative degree? Are you talking about radians?

7. ## Re: Need Help

what you mean by negative degree?
new GeoLocation(48.87, -2.33);

I dont remember how to do the great circle distance.
It would be important to have the correct formula.

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## Re: Need Help

Oh, That's what the output supposed to look like. I got all of the output correct except for the great circle one , which I have no idea how to do and working on it right now. I forgot the great circle distance formula...

9. ## Re: Need Help

What are negative degrees?

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## Re: Need Help

for Trig functions? If so isn't it Reciprocal? Sin-1 , Cos -1 , Tan -1

11. ## Re: Need Help

Originally Posted by xdrazkalnytex
... I forgot the great circle distance formula...
That can be looked up.

*Edit* and shoot, I just found it in 2 seconds on Wikipedia. I'm betting you can too.

12. ## Re: Need Help

If you do not know what negative degrees are, how can you use them correctly?

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## Re: Need Help

i don't remember anything about negative degrees. That's the thing

14. ## Re: Need Help

Degrees for positions are either: N, S, E or W
- must be one of those.

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## Re: Need Help

So negative degrees would be the opposite - N, - S, -E, -W

16. ## Re: Need Help

There are no such thing as negative degrees when designation a location on earth. You use the - to chose either E or W or N or S
What is the -2.33? Is that East or West longitude? Is that in Paris or Brest?
Last edited by Norm; 04-24-2012 at 03:29 AM.

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## Re: Need Help

Oh. I got it. Thanks a lot Norm. You were helpful.

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