Formula to cacluate the Bearing angle in degrees between two points

[Arjuun Sethuraman]

Hi, 

I have a requirement where in I need to calculate the bearing angle in degree wrt N between two coordinates. I want a formula which would do that. The coordinates are in Deg Min Sec format. 

Someone kindly help me out..

Cheers

Arjuun

[Robert Crossley]

Just working on it in SQL server now.  You didn’t mention what program you were working in?

 

This is the function in SQL for decimal degrees – you may have to preprocess to get to decimal degrees from minutes/ second.

 

ATan 2 function is not always available, but there is ways of workiing around it.  I think I have posted some in the past.

 

A good reference is:

http://www.movable-type.co.uk/scripts/latlong.html

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[Arjuun Sethuraman]

I need this to be on a excel sheet. this is for a small temporary use. we are using mapinfo for plotting all the location. 

regards

arjuun

[Robert Crossley]

The same formula should be available then.

[Arjuun Sethuraman]

yeah it basically gives two things initial and final bearing angle. my requirement is this, i have a point to point radio, one at location A and location B. So i need to know in which direction I should point the radio in location A and location B. So once i enter the coordinates of location A and B. I want to know what direction i should point the radio at Location A. 

[Gentreau]

Well that would be the initial bearing then, no ?

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From: mapi...@googlegroups.com [mailto:mapi...@googlegroups.com] On Behalf Of Arjuun Sethuraman

Sent: Tuesday, May 12, 2009 9:34 AM

[nestor olfindo]

you can use the geodetic direct (or maybe the geodetic inverse) equation. the algorithm can be found in the net. vincenty's equation is a good choice.

nestor

[Glen]

the magical document has all the answeres you seek


http://williams.best.vwh.net/avform.htm#Crs

[Glen]

http://www.movable-type.co.uk/scripts/latlong.html << cool web page

that would make a great Excel sheet to keep with you??

[Ian Tidy]

Be careful, aligning radio antenna with co-ordinates doesn't always give you the best signal strength.  I found that on shorter hauls (between 1 - 20k), in some environments, the antennas needed to be off centre.  And you have the added problem of measuring the same north in both your mapping system and onsite.

 

To calculate the angle between the sites have a look at:

http://www.teacherschoice.com.au/Maths_Library/Coordinates/polar_-_rectangular_conversion.htm or http://www.mathwords.com/p/polar_rectangular_conversion_formulas.htm or the results from http://www.google.com/search?q=polar+rectangular+conversion&rls=com.microsoft:en-US&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1

 

Hope this helps

 

Regards Ian

 

______________________
Ian Tidy
GIS Analyst / Developer
Works Asset Department
Napier City Council
Skype ian.tidy.ncc
mailto:ia...@napier.govt.nz
http://www.napier.govt.nz | http://maps.napier.govt.nz

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