Java tutorial
/* Copyright 2002-2015 CS Systmes d'Information * Licensed to CS Systmes 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. */ package fr.cs.examples.propagation; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.PrintStream; import java.net.URISyntaxException; import java.text.DecimalFormat; import java.text.DecimalFormatSymbols; import java.util.ArrayList; import java.util.List; import java.util.Locale; import org.apache.commons.math3.util.FastMath; import org.orekit.bodies.BodyShape; import org.orekit.bodies.GeodeticPoint; import org.orekit.bodies.OneAxisEllipsoid; import org.orekit.errors.OrekitException; import org.orekit.frames.FramesFactory; import org.orekit.frames.TopocentricFrame; import org.orekit.utils.Constants; import org.orekit.utils.IERSConventions; import fr.cs.examples.Autoconfiguration; import fr.cs.examples.KeyValueFileParser; /** Orekit tutorial for computing visibility circles. * @author Luc Maisonobe */ public class VisibilityCircle { /** Program entry point. * @param args program arguments */ public static void main(String[] args) { try { // configure Orekit Autoconfiguration.configureOrekit(); // input/out File input = new File(VisibilityCircle.class.getResource("/visibility-circle.in").toURI().getPath()); File output = new File(input.getParentFile(), "visibility-circle.csv"); new VisibilityCircle().run(input, output, ","); System.out.println("visibility circle saved as file " + output); } catch (URISyntaxException use) { System.err.println(use.getLocalizedMessage()); System.exit(1); } catch (IOException ioe) { System.err.println(ioe.getLocalizedMessage()); System.exit(1); } catch (IllegalArgumentException iae) { System.err.println(iae.getLocalizedMessage()); System.exit(1); } catch (OrekitException oe) { System.err.println(oe.getLocalizedMessage()); System.exit(1); } } /** Input parameter keys. */ private static enum ParameterKey { STATION_NAME, STATION_LATITUDE, STATION_LONGITUDE, STATION_ALTITUDE, MIN_ELEVATION, SPACECRAFT_ALTITUDE, POINTS_NUMBER; } private void run(final File input, final File output, final String separator) throws IOException, IllegalArgumentException, OrekitException { // read input parameters KeyValueFileParser<ParameterKey> parser = new KeyValueFileParser<ParameterKey>(ParameterKey.class); parser.parseInput(new FileInputStream(input)); double minElevation = parser.getAngle(ParameterKey.MIN_ELEVATION); double radius = Constants.WGS84_EARTH_EQUATORIAL_RADIUS + parser.getDouble(ParameterKey.SPACECRAFT_ALTITUDE); int points = parser.getInt(ParameterKey.POINTS_NUMBER); // station properties double latitude = parser.getAngle(ParameterKey.STATION_LATITUDE); double longitude = parser.getAngle(ParameterKey.STATION_LONGITUDE); double altitude = parser.getDouble(ParameterKey.STATION_ALTITUDE); String name = parser.getString(ParameterKey.STATION_NAME); // compute visibility circle List<GeodeticPoint> circle = computeCircle(latitude, longitude, altitude, name, minElevation, radius, points); // create a 2 columns csv file representing the visibility circle // in the user home directory, with latitude in column 1 and longitude in column 2 DecimalFormat format = new DecimalFormat("#00.00000", new DecimalFormatSymbols(Locale.US)); PrintStream csvFile = new PrintStream(output); for (GeodeticPoint p : circle) { csvFile.println(format.format(FastMath.toDegrees(p.getLatitude())) + "," + format.format(FastMath.toDegrees(p.getLongitude()))); } csvFile.close(); } private static List<GeodeticPoint> computeCircle(double latitude, double longitude, double altitude, String name, double minElevation, double radius, int points) throws OrekitException { // define Earth shape, using WGS84 model BodyShape earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010, false)); // define an array of ground stations TopocentricFrame station = new TopocentricFrame(earth, new GeodeticPoint(latitude, longitude, altitude), name); // compute the visibility circle List<GeodeticPoint> circle = new ArrayList<GeodeticPoint>(); for (int i = 0; i < points; ++i) { double azimuth = i * (2.0 * FastMath.PI / points); circle.add(station.computeLimitVisibilityPoint(radius, azimuth, minElevation)); } // return the computed points return circle; } }