GeographicLib

[jonsberndt]

I just noticed the inclusion of GeographicLib - in particular for calculating waypoint characteristics. Very nice. Does the fact that it uses a different license cause any issues?

[seanmcleod]

So JSBSim is using the GNU Lesser General Public License (GNU LGPL) and GeographicLib is using the more permissive MIT/X11 license.

From the GNU licenses FAQ - https://www.gnu.org/licenses/gpl-faq.en.html

The X11 license is compatible with the GPL, so you can add a module to the GPL-covered program and put it under the X11 license. But if you were to incorporate them both in a larger program, that whole would include the GPL-covered part, so it would have to be licensed as a whole under the GNU GPL.

So I don't see any specific issue.

[jonsberndt]

Seems to be an error in the call to GetDistanceTo (from FGWaypoint). I don't have time to debug this, but I'm stepping through the code with:

Target lat: -1.982100
Target lon: 0.700800

and calling GetDistanceTo from within FGWayPoint and get a floating point exception:

cout << "Target lat: " << target_latitude_rad << endl;
cout << "Target lon: " << target_longitude_rad << endl;
double wp_distance = source.GetDistanceTo(target_longitude_rad,
target_latitude_rad);

Maybe I can look at this later, but it would be better if someone familiar with the GeographicLib could take a look. Are negative numbers supported? Are there any limitations to the code? Is the great circle distance returned?

[seanmcleod]

Take a look at this issue - #475

What compiler are you using?

You mention the target's coordinates, what were are the source's coordinates? Are source and target extremely close?

[jonsberndt]

The source coords are just the current location. I guess since this is a first-frame problem I should print out the coords and verify that they are good. That could well be the issue: uninitialized coordinates. Here's my XML:

		<waypoint_distance name="system/distance-to-dugway" unit="FT">
			  <target_latitude unit="RAD">  location/site_long_rad </target_latitude>
			  <target_longitude unit="RAD"> location/site_lat_rad </target_longitude>
			  <source_latitude unit="RAD">  position/lat-geod-rad </source_latitude>
			  <source_longitude unit="RAD"> position/long-gc-rad </source_longitude>
		</waypoint_distance>	

[jonsberndt]

Well, the current location is fine.

[jonsberndt]

Further info: compilation is being done under Cygwin 64 on a Windows 10 machine.

[jonsberndt]

Ugh. I'm an idiot.

	<waypoint_distance name="system/distance-to-dugway" unit="FT">
		  <target_**latitude** unit="RAD">  location/site_**long**_rad </target_latitude>
		  <target_**longitude** unit="RAD"> location/site_**lat**_rad </target_longitude>
		  <source_latitude unit="RAD">  position/lat-geod-rad </source_latitude>
		  <source_longitude unit="RAD"> position/long-gc-rad </source_longitude>
	</waypoint_distance>	

Maybe there should be some kind of a bounds check in the code for idiots? LoL.

[bcoconni]

Maybe there should be some kind of a bounds check in the code for idiots? LoL.

Well, JSBSim should never crash even when supplied with silly data. Could you please fill a bug report ?