FOAK: working out distances using lat & long

I'm a bit stuck here - should have been a bit more attentive at school..

Using VB script for a web page, how do you work out the distance between two
places, both of known longtitude and latitude.

Basically what I want to be able to do is enter a place and find everything
in a database say less than a mile from this one point.

I'm sure it's easy if you know how - buggered if I do.

TIA

Buzby

 

I can remember finding some code to do just this about 30 years ago, and
using it on a variety of machines from HP desktop calculators, through BBC
Micros, to Acorn RISC machines. It was published in Radio Communication
yonks ago, but I don't have a copy. Radio amateurs often need to work out
Great Circle distances between two stations anywhere on the surface of the
Earth, but normally they will be using a program written by someone else,
rather than coding it themselves.

If no joy, I think that an enquiry on uk.radio.amateur would bear fruit.

Good hunting

Rick

 

Thanks - however just managed to 'lift and adapt' something which seems
surprisingly accurate!

 

It's called "Great Circle Navigation", probably.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, mb

It is, but for small distances a rhumb line works pretty well. For a
mile, it'd be more than accurate enough.
--
Nigel - Manufacturer of the "Champion-105" range of rearsets

WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41
ZZR1100, Enfield 500 Curry House Racer "The Basmati Rice Burner",
Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big"

 

Not needed for distances of a mile or so.
For the distance between two points:

Take the difference in latitude in degrees, multiply by 10000 and
divide by 90 to get it in kilometres.

Do the same for longitude but multiply by the cosine of the latitude.

Take the square root of the sum of the squares of the above two values
and Bob's your uncle.

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, Champ

**** me! AFAIC, it's just a straight line on a chart.

Having looked at that webpage, I'll never go to sea again.

--
Nigel - Manufacturer of the "Champion-105" range of rearsets

WS* GHPOTHUF#24 APOSTLE#14 DLC#1 COFF#20 BOTAFOT#150 HYPO#0(KoTL) IbW#41
ZZR1100, Enfield 500 Curry House Racer "The Basmati Rice Burner",
Honda GL1000K2 (On its hols) Kawasaki ZN1300 Voyager "Oh, Oh, It's so big"

 

It was somewhere around Barstow, on the edge of the desert, when the

Eek!

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

 

Perfect. Thanks very much.

 

I had to study (nautical) navigation when I was about 17, but I don't
think we ever approached it in that way. Instead we based it all on
3-d trigonometry, using cosh, shin and than h for hyperbolic, IIRC).

Piece of piss in practice, as they work for a shape (line, engle,
whatever) on a sphere's surface in exactly the same way as their
normal cousins on a flat surface.