how to get the longitude and latitude ?

[skywalker]

I tried to get them like this:

FlightProperties * fdm=new FlightProperties ;
float lon=fdm->get_Longitude()*SGD_DEGREFS_TO_RADIANS;
float lat=fdm->get_Latitude()*SGD_DEGREFS_TO_RADIANS;


while I can't get the lon,and lat. could anybody help me ? thanks a lot!!

[Hooray]

I think you need to provide a little more background information.
Otherwise, just getting the current lat/lon is as simple as using fgGetDouble("/position/latitude-deg"); and fgGetDouble("/position/longitude-deg");

[Gijs]

thanks for your reply! I want to draw my own HUD, I need to know the current lat/lon when the plane is flying~ . I will try your method~ thanks for your help~

[skywalker]

I think you need to provide a little more background information.
Otherwise, just getting the current lat/lon is as simple as using fgGetDouble("/position/latitude-deg"); and fgGetDouble("/position/longitude-deg");

I have tried your way,but what I have got are constant. I want to get the quantity,which will change as the plane flying~
waiting for your reply~ thanks!

[Hooray]

post your code (or use the devel mailing list)

[Gijs]

Do you really want to design a new HUD system, or just edit the way the HUD looks and the data it visualises? For the later you don't need to edit source. Check Docs/README.hud for more info on making a custom HUD.

[Hooray]

He posted C++ code, and he said he wanted to draw a custom HUD, so he'll probably want to use C++.
On the other hand, the new canvas system could be another option: http://wiki.flightgear.org/Canvas_Properties

[skywalker]

thanks for your replies~

this is part of my code:

HUD_my.cxx

... ....
_longitude(fgGetDouble("/position/longitude-deg"));
_latitude(fgGetDouble("/position/latitude-deg"));
... ...
fromwp_lon=_longitude;
fromwp_lat= _latitude;
towp_lon=100.111111111;
towp_lat=50.111111111;
dis= towp_lat-fromwp_lat;
... ...
//*** it will draw a line in the HUD ***
glBegin(GL_LINE_STRIP);
glVertext2f(_x,_y);
glVertext2f(_x+dis*10,_y);
glEnd();
... ...



I think the length of the line will modify when the plane is flying,because the dis is changing;

while the line I get is not change any more~~

[Hooray]

you need to post a complete, sensible, snippet of your code - such as a whole function (i.e. SGSubsystem::update()) or at least the loop updating your HUD.
The code you have posted is far too incomplete to provide any useful feedback in my opinion. There are too many factors here.
Obviously, you need to update your HUD continuously, i.e. within the update() method of your subsystem.

Also, when you post your code, please use BB-code code tags - or use a pastebin like www.codepad.org

[skywalker]

Hooray:
Thank you!
I have resolved my problem.
Some of the code is not allowed to given out,I am sorry ~. Thanks for all your replies,wishing the BBS get better and better~