Re: [Orekit Users] CelestialBody.getPVCoordinates() not working in Python

[Petrus Hyvönen <petrus.hyvonen@gmail.com>]

Hi, 

I'm not really sure why but sometimes you need to clarify to the object what they can be by casting them.

do a:
from org.orekits.utils import PVCoordinatesProvider 
moon = PVCoordinatesProvider.cast_(moon)

This will make it work.

Regards
/Petrus


On 20 Mar 2014, at 20:57 , <ltrom1@gmail.com> <ltrom1@gmail.com> wrote:

> Hi everybody,
> I just got started today with Orekit, and I used JCC to integrate it in Python
> 2.7.
> I tried to run the demo python script from the wiki page and it worked fine.
> I am now trying to get the Moon position in EME2000 frame but the last line of
> the script below returns the error {'CelestialBody' object has no attribute
> 'getPVCoordinates'}:
> =========================================================
> import orekit
> orekit.initVM()
> 
> from java.io import File
> from org.orekit.data import DataProvidersManager, ZipJarCrawler
> from org.orekit.time import TimeScalesFactory, AbsoluteDate
> from org.orekit.frames import FramesFactory
> from org.orekit.bodies import CelestialBodyFactory
> 
> #Setup Orekit:
> DM = DataProvidersManager.getInstance()
> datafile = File('lib/xtra/orekit/orekit-data.zip')
> if datafile.exists() == False:
>    print 'File :', datafile.absolutePath, ' not found'
> 
> crawler = ZipJarCrawler(datafile)
> DM.clearProviders()
> DM.addProvider(crawler)
> 
> #Get Moon position:
> utc = TimeScalesFactory.getUTC()
> gei = FramesFactory.getEME2000()
> moon = CelestialBodyFactory.getMoon()
> 
> date = AbsoluteDate(2014, 01, 01, 00, 00, 00.000, utc)
> print moon.getPVCoordinates(date,gei).getPosition()
> =========================================================
> 
> So I tried the following java code, and it worked fine so it's not helping me
> to understand what's wrong in my Python code. Now it's been a couple of hours
> I am fighting against this problem, but maybe there is somebody here who could
> give me some hints to get my python script working.
> Thanks in advance!
> 
> =========================================================
> 
> import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
> import org.orekit.bodies.CelestialBody;
> import org.orekit.bodies.CelestialBodyFactory;
> import org.orekit.errors.OrekitException;
> import org.orekit.frames.Frame;
> import org.orekit.frames.FramesFactory;
> import org.orekit.time.AbsoluteDate;
> import org.orekit.time.TimeScale;
> import org.orekit.time.TimeScalesFactory;
> import fr.cs.examples.Autoconfiguration;
> 
> public class test_01 {
> 
>    public static void main(String[] args) {
>        try {
>            Autoconfiguration.configureOrekit();
> 
>            TimeScale utc = TimeScalesFactory.getUTC();
>            Frame gei = FramesFactory.getEME2000();
>            CelestialBody moon = CelestialBodyFactory.getMoon();
> 
>            AbsoluteDate date = new AbsoluteDate(2014, 01, 01, 00, 00, 00,
> utc);
>            Vector3D pos_Moon = moon.getPVCoordinates(date,
> gei).getPosition();
>            System.out.println(pos_Moon);
> 
>        } catch (OrekitException oe) {
>            System.err.println(oe.getMessage());
>        }
>    }
> }
> =========================================================