Added Example of plain python usage of orekit through a translated NodeDetectorTest

examples/NodeDetectorTest.py

+"""This is a Python translation of the java NodeDetectorTest.java that is part of the orekit test suite. 
+
+/* Copyright 2002-2013 CS mes d'Information (CS) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * CS licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+Modifications and translation to python by Petrus Hyvonen, SSC 2014
+
+"""
+
+
+import orekit
+orekit.initVM()
+
+from orekit import JArray_double
+from orekit.pyhelpers import setup_orekit_curdir
+from math import radians
+
+from org.orekit.propagation.events import EventsLogger
+from org.orekit.propagation.events import NodeDetector
+
+from org.apache.commons.math3.ode.nonstiff import DormandPrince853Integrator;
+from org.orekit.frames import FramesFactory;
+from org.orekit.orbits import KeplerianOrbit;
+from org.orekit.orbits import PositionAngle;
+from org.orekit.propagation import SpacecraftState;
+from org.orekit.propagation.events.handlers import ContinueOnEvent;
+from org.orekit.propagation.numerical import NumericalPropagator;
+from org.orekit.time import AbsoluteDate;
+from org.orekit.time import TimeScalesFactory;
+from org.orekit.utils import Constants;
+
+setup_orekit_curdir()   # orekit-data.zip shall be in current dir
+
+# Floats are needed to be specific in the orekit interface
+a = 800000.0 + Constants.WGS84_EARTH_EQUATORIAL_RADIUS;
+e = 0.0001;
+i = radians(98.0);
+w = -90.0;
+raan = 0.0;
+v = 0.0;
+
+inertialFrame = FramesFactory.getEME2000();
+initialDate = AbsoluteDate(2014, 01, 01, 0, 0, 0.0, TimeScalesFactory.getUTC());
+finalDate = initialDate.shiftedBy(5000.0);
+initialOrbit = KeplerianOrbit(a, e, i, w, raan, v, PositionAngle.TRUE, inertialFrame, initialDate, Constants.WGS84_EARTH_MU);
+initialState = SpacecraftState(initialOrbit, 1000.0);
+
+tol = NumericalPropagator.tolerances(10.0, initialOrbit, initialOrbit.getType());
+
+# Double array of doubles needs to be retyped to work
+integrator = DormandPrince853Integrator(0.001, 1000.0, 
+    JArray_double.cast_(tol[0]),
+    JArray_double.cast_(tol[1]))
+
+propagator = NumericalPropagator(integrator);
+propagator.setInitialState(initialState);
+
+# Define 2 instances of NodeDetector:
+rawDetector = NodeDetector(1e-6, 
+        initialState.getOrbit(), 
+        initialState.getFrame()).withHandler(ContinueOnEvent().of_(NodeDetector))
+        # Converted withHandler(ContinueOnEvent<NodeDetector>());
+
+logger1 = EventsLogger();
+node1 = logger1.monitorDetector(rawDetector);
+logger2 = EventsLogger();
+node2 = logger2.monitorDetector(rawDetector);
+
+propagator.addEventDetector(node1);
+propagator.addEventDetector(node2);
+
+# First propagation
+propagator.setEphemerisMode();
+propagator.propagate(finalDate);
+
+assert 2==logger1.getLoggedEvents().size()
+assert 2== logger2.getLoggedEvents().size();
+
+logger1.clearLoggedEvents();
+logger2.clearLoggedEvents();
+
+postpro = propagator.getGeneratedEphemeris();
+
+# Post-processing
+postpro.addEventDetector(node1);
+postpro.addEventDetector(node2);
+postpro.propagate(finalDate);
+
+assert 2==logger1.getLoggedEvents().size()
+assert 2==logger2.getLoggedEvents().size()
+
+