View Full Version : world coordinates vs lat/long

mochi

07-10-2001, 11:19 PM

sorry ... i got question again ...

has anyone convert lat/long values into coordinates??

Does anyone know what is the relationship??

cheers

omkar26

07-11-2001, 01:09 AM

as far as i know lat/long is used to specify a particular position on earth.

For your case you consider a 2-d plane where the divs on the x-axis are given by the longitudes, and the divs on the y axis are given by the latitudes.

The more the no of long./lat the more is the precision on the resp axes.

mochi

07-11-2001, 06:39 PM

thanks for helping ... though i dun really understand what u mean ... can perhaps give me an example?? =p

RedZen

07-12-2001, 12:00 AM

hmmm I don't if you use different coordinate values than we do here. But considering that you get degrees, minutes and seconds.

It's too simple, and I guess this is not what you are looking for, but if the value is

45 out of 60(where 60 is maximum) you can get it out of 100, by multiplying the value by a 100, and then deviding by 60. The same goes for 360 and so forth, it works on the same principal. And thats how you get the degrees into something usuable.

Lat/Long is just telling you where you are.

What you have to do is to combert them to usable units like meters.

In Geography, UTM (Universal Transverse Mercator) coordinate system is commonly used. It can convert lat/long to meters.

There are tons of sites explaining it.

RCMaster

07-12-2001, 04:47 AM

Just apply these formulas :

x = radius * cos lat * cos long

y = radius * cos lat * sin long

z = radius * sin lat

http://www.opengl.org/discussion_boards/ubb/confused.gif

[This message has been edited by RCMaster (edited 07-12-2001).]

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