How do you compute distance between 2 Lat/Long

[MD11Drvr]

How about at normal ground speeds in a jet. You pick what norm is. Say at .82, 10mins = 2degrees long, it is a pretty good wag. Try it. Not scientific but it will get you there.
Its a wrap, put it on the plot chart....

Birdman
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On tour with the 101st now

fatboyplt,

A sincere THANK YOU for your service!:beer:

MD11Drvr (Now back in the DC-10)

 

[AvroJockey]

here is the EXACT methodology. perhaps a shortcut can be seen from this.

we will use ORD (41 58' 42.972" N x 87 54' 17.429" W) to LAX (33 56' 33.1301" N x 118 24' 29.068" W)

convert to decimals so for ex. 41 + (58 + (42.972/60))/60 = 41.9786033. It will be negative if S and W. Thus ORD (41.9786033, -87.904841) to LAX (33.9425361, -118.40807).

convert the decimals values to radians by multiplying them by PI/180. so for ex. 41.9786033 x PI / 180 = .73266484. Thus ORD (0.73266484, -1.5342289) to LAX (0.59240901, -2.066108).

calculate the SIN and COS of each latitude and longitude value.

The formula is:

ARCCOS (SIN(Lat1) SIN(Lat2) + COS(Lat1) COS (Lat2) COS(Long2-Long1)) x (180/PI) X 60

The 180/PI is to convert back to degrees and 60 is the number of nm per degree of lat/long.

For ORD to LAX the value is 1512.00272.

Basically you are measuring arc distance and that is where the math comes from. The radius of the earth is a constant and thus from the center of the earth to each lat/long coord is the radius of the earth plus its field elevation above MSL. then with two sides of the triangle known and the angle between the two calculated (the arc cosine value) the arc length can be calculated.

http://www.themathpage.com/aTrig/arc-length.htm

Your frequent flier miles will be credited.....

IF this is the easy "mental math" way. I'm a moron!
I guess I'll just keep killing brain cells.:beer:

 

[pilotyip]

every degree of latitude ='s 60 NMs. Every minute of latitude ='s 1 NM. One minute of evation, measured with your sextant, of a celestial body upon a great circle ='s 1 NM. Take your divers, lay it on the line you want to measure, find the lenght. Then lay the dividers upon a line of longitude and measue how many degrees and minutes of latitude you have. That ='s the NM of the line. Cel Nav 101 VT-29 Corpus Christi, TX 1968.

 

[Falconjet]

You should have taken some English and spelling lessons in trade school Yip. Maybe typing too.

FJ

 

[Guam360]

This is what dividers are for, use your dividers spread them across the the two points, without moving them, lay them across the nearest longitude line using latitude as your measurement, 60NM per degree and this is your distance......basic navigation. then apply time/dist/speed to your DR if you are lost or have no fix info.

but we all have FMS (PFM)

sorry Yip, you beat me to it.

 

[pilotyip]

Navy's fault

You should have taken some English and spelling lessons in trade school Yip. Maybe typing too.

FJ

They had their chance to teach me to speel, but they never did it. They might have tried for 26 years but they never got there. BTW Am I being graded on my sppeling?

 

[dash8driver]

here is the EXACT methodology. perhaps a shortcut can be seen from this.

we will use ORD (41 58' 42.972" N x 87 54' 17.429" W) to LAX (33 56' 33.1301" N x 118 24' 29.068" W)

convert to decimals so for ex. 41 + (58 + (42.972/60))/60 = 41.9786033. It will be negative if S and W. Thus ORD (41.9786033, -87.904841) to LAX (33.9425361, -118.40807).

convert the decimals values to radians by multiplying them by PI/180. so for ex. 41.9786033 x PI / 180 = .73266484. Thus ORD (0.73266484, -1.5342289) to LAX (0.59240901, -2.066108).

calculate the SIN and COS of each latitude and longitude value.

The formula is:

ARCCOS (SIN(Lat1) SIN(Lat2) + COS(Lat1) COS (Lat2) COS(Long2-Long1)) x (180/PI) X 60

The 180/PI is to convert back to degrees and 60 is the number of nm per degree of lat/long.

For ORD to LAX the value is 1512.00272.

Basically you are measuring arc distance and that is where the math comes from. The radius of the earth is a constant and thus from the center of the earth to each lat/long coord is the radius of the earth plus its field elevation above MSL. then with two sides of the triangle known and the angle between the two calculated (the arc cosine value) the arc length can be calculated.

http://www.themathpage.com/aTrig/arc-length.htm

Your frequent flier miles will be credited.....

this post is completely inappropriate for this forum. where do you get off posting accurate technical information on here? it would have been a little more acceptable if you were able to work a "mesa sucks" or something in there.

this place is going downhill.

 

[bmxandjets]

this post is completely inappropriate for this forum. where do you get off posting accurate technical information on here? it would have been a little more acceptable if you were able to work a "mesa sucks" or something in there.

this place is going downhill.

that is funny...i don't care who you are!