Ricky Barrette
449c97a384
I moved this method from FMC Change-Id: I61ff03c3e69a32cabb1999cb858b139990f2f835 Signed-off-by: Ricky Barrette <rickbarrette@gmail.com>
283 lines
11 KiB
Java
283 lines
11 KiB
Java
/**
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* @author Twenty Codes, LLC
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* @author Google Inc.
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* @author ricky barrette
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* @date Oct 2, 2010
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*
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* Some Code here is Copyright (C) 2008 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.TwentyCodes.android.location;
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import java.text.DecimalFormat;
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import java.util.ArrayList;
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import java.util.List;
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import android.graphics.Point;
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import com.google.android.maps.GeoPoint;
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import com.google.android.maps.MapView;
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/**
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* This class contains common tools for computing common geological problems
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* @author ricky barrette
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* @author Google Inc.
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*/
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public class GeoUtils {
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public static final int EARTH_RADIUS_KM = 6371;
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public static final double MILLION = 1000000;
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/**
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* Calculates the bearing from the user location to the destination location, or returns the bearing for north if there is no destination.
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* This method is awesome for make a compass point toward the destination rather than North.
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* @param user location
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* @param dest location
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* @param bearing Degrees East from compass
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* @return Degrees East of dest location
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* @author ricky barrette
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*/
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public static float calculateBearing(GeoPoint user, GeoPoint dest, float bearing) {
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if( (user == null) || (dest == null) )
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return bearing;
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float heading = bearing(user, dest).floatValue();
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bearing = (360 - heading) + bearing;
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if (bearing > 360)
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return bearing - 360;
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return bearing;
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}
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/**
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* computes the bearing of lat2/lon2 in relationship from lat1/lon1 in degrees East
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* @param lat1 source lat
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* @param lon1 source lon
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* @param lat2 destination lat
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* @param lon2 destination lon
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* @return the bearing of lat2/lon2 in relationship from lat1/lon1 in degrees East of true north
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* @author Google Inc.
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*/
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public static double bearing(double lat1, double lon1, double lat2, double lon2) {
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double lat1Rad = Math.toRadians(lat1);
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double lat2Rad = Math.toRadians(lat2);
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double deltaLonRad = Math.toRadians(lon2 - lon1);
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double y = Math.sin(deltaLonRad) * Math.cos(lat2Rad);
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double x = Math.cos(lat1Rad) * Math.sin(lat2Rad) - Math.sin(lat1Rad) * Math.cos(lat2Rad) * Math.cos(deltaLonRad);
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return radToBearing(Math.atan2(y, x));
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}
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/**
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* computes the bearing of lat2/lon2 in relationship from lat1/lon1 in degrees East of true north
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* @param p1 source geopoint
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* @param p2 destination geopoint
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* @return the bearing of p2 in relationship from p1 in degrees East
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* @author Google Inc.
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*/
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public static Double bearing(GeoPoint p1, GeoPoint p2) {
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double lat1 = p1.getLatitudeE6() / MILLION;
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double lon1 = p1.getLongitudeE6() / MILLION;
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double lat2 = p2.getLatitudeE6() / MILLION;
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double lon2 = p2.getLongitudeE6() / MILLION;
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return bearing(lat1, lon1, lat2, lon2);
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}
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/**
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* Calculates a geopoint x meters away of the geopoint supplied. The new geopoint
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* shares the same latitude as geopoint point, this way they are on the same latitude arc.
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*
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* @param point central geopoint
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* @param distance in meters from the geopoint
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* @return geopoint that is x meters away from the geopoint supplied
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* @author ricky barrette
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*/
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public static GeoPoint distanceFrom(GeoPoint point, double distance){
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//convert meters into kilometers
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distance = distance / 1000;
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// convert lat and lon of geopoint to radians
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double lat1Rad = Math.toRadians((point.getLatitudeE6() / 1e6));
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double lon1Rad = Math.toRadians((point.getLongitudeE6() / 1e6));
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/*
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* kilometers = acos(sin(lat1Rad)sin(lat2Rad)+cos(lat1Rad)cos(lat2Rad)cos(lon2Rad-lon1Rad)6371
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*
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* we are solving this equation for lon2Rad
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*
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* lon2Rad = lon1Rad+acos(cos(meters/6371)sec(lat1Rad)sec(lat2Rad)-tan(lat1Rad)tan(lat2Rad))
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*
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* NOTE: sec(x) = 1/cos(x)
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*
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* NOTE: that lat2Rad is = lat1Rad because we want to keep the new geopoint on the same lat arc
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* therefore i saw no need to create a new variable for lat2Rad,
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* and simply inputed lat1Rad in place of lat2Rad in the equation
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*
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* NOTE: this equation has be tested in the field against another gps device, and the distanceKm() from google
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* and has been proven to be damn close
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*/
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double lon2Rad = lon1Rad + Math.acos( Math.cos((distance/6371)) * (1 / Math.cos(lat1Rad))
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* (1 / Math.cos(lat1Rad)) - Math.tan(lat1Rad) * Math.tan(lat1Rad));
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//return a geopoint that is x meters away from the geopoint supplied
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return new GeoPoint(point.getLatitudeE6(), (int) (Math.toDegrees(lon2Rad) * 1e6));
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}
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/**
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* computes the distance between to lat1/lon1 and lat2/lon2 based on the curve of the earth
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* @param lat1 source lat
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* @param lon1 source lon
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* @param lat2 destination lat
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* @param lon2 destination lon
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* @return the distance between to lat1/lon1 and lat2/lon2
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* @author Google Inc.
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*/
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public static double distanceKm(double lat1, double lon1, double lat2, double lon2) {
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double lat1Rad = Math.toRadians(lat1);
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double lat2Rad = Math.toRadians(lat2);
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double deltaLonRad = Math.toRadians(lon2 - lon1);
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return Math.acos(Math.sin(lat1Rad) * Math.sin(lat2Rad) + Math.cos(lat1Rad) * Math.cos(lat2Rad) * Math.cos(deltaLonRad)) * EARTH_RADIUS_KM;
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}
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/**
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* Converts distance into a human readbale string
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* @param distance in kilometers
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* @param returnMetric true if metric, false for US
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* @return string distance
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* @author ricky barrette
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*/
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public static String distanceToString(double distance, boolean returnMetric) {
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DecimalFormat threeDForm = new DecimalFormat("#.###");
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DecimalFormat twoDForm = new DecimalFormat("#.##");
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if (returnMetric) {
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if (distance < 1) {
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distance = distance * 1000;
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return twoDForm.format(distance) + " m";
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}
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return threeDForm.format(distance) + " Km";
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}
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distance = distance / 1.609344;
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if (distance < 1) {
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distance = distance * 5280;
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return twoDForm.format(distance) + " ft";
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}
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return twoDForm.format(distance) + " mi";
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}
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/**
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* a convince method for testing if 2 circles on the the surface of the earth intersect.
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* we will use this method to test if the users accuracy circle intersects a marked locaton's radius
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* if ( (accuracyCircleRadius + locationRadius) - fudgeFactor) > acos(sin(lat1Rad)sin(lat2Rad)+cos(lat1Rad)cos(lat2Rad)cos(lon2Rad-lon1Rad)6371
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* @param userPoint
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* @param accuracyRadius in KM
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* @param locationPoint
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* @param locationRadius in KM
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* @param fudgeFactor how many KM the circles have to intersect
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* @return true if the circles intersect
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* @author ricky barrette
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*/
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public static boolean isIntersecting(GeoPoint userPoint, float accuracyRadius, GeoPoint locationPoint, float locationRadius, float fudgeFactor){
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if(((accuracyRadius + locationRadius) - fudgeFactor) > distanceKm(locationPoint, userPoint))
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return true;
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return false;
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}
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/**
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* computes the distance between to p1 and p2 based on the curve of the earth
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* @param p1
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* @param p2
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* @return the distance between to p1 and p2
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* @author Google Inc.
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*/
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public static double distanceKm(GeoPoint p1, GeoPoint p2) {
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//if we are handed a null, return -1 so we don't break
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if(p1 == null || p2 == null)
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return -1;
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double lat1 = p1.getLatitudeE6() / MILLION;
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double lon1 = p1.getLongitudeE6() / MILLION;
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double lat2 = p2.getLatitudeE6() / MILLION;
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double lon2 = p2.getLongitudeE6() / MILLION;
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return distanceKm(lat1, lon1, lat2, lon2);
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}
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/**
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* determines when the specified point is off the map
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* @param point
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* @return true is the point is off the map
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* @author ricky barrette
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*/
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public static boolean isPointOffMap(MapView map , GeoPoint point){
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if(map == null)
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return false;
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if (point == null)
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return false;
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GeoPoint center = map.getMapCenter();
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double distance = GeoUtils.distanceKm(center, point);
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double distanceLat = GeoUtils.distanceKm(center, new GeoPoint((center.getLatitudeE6() + (int) (map.getLatitudeSpan() / 2)), center.getLongitudeE6()));
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double distanceLon = GeoUtils.distanceKm(center, new GeoPoint(center.getLatitudeE6(), (center.getLongitudeE6() + (int) (map.getLongitudeSpan() / 2))));
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if (distance > distanceLat || distance > distanceLon){
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return true;
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}
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return false;
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}
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/**
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* computes a geopoint the is the central geopoint between p1 and p1
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* @param p1 first geopoint
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* @param p2 second geopoint
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* @return a MidPoint object
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* @author ricky barrette
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*/
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public static MidPoint midPoint(GeoPoint p1, GeoPoint p2) {
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int minLatitude = (int)(+81 * 1E6);
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int maxLatitude = (int)(-81 * 1E6);
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int minLongitude = (int)(+181 * 1E6);
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int maxLongitude = (int)(-181 * 1E6);
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List<Point> mPoints = new ArrayList<Point>();
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int latitude = p1.getLatitudeE6();
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int longitude = p1.getLongitudeE6();
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if (latitude != 0 && longitude !=0) {
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minLatitude = (minLatitude > latitude) ? latitude : minLatitude;
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maxLatitude = (maxLatitude < latitude) ? latitude : maxLatitude;
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minLongitude = (minLongitude > longitude) ? longitude : minLongitude;
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maxLongitude = (maxLongitude < longitude) ? longitude : maxLongitude;
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mPoints.add(new Point(latitude, longitude));
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}
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latitude = p2.getLatitudeE6();
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longitude = p2.getLongitudeE6();
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if (latitude != 0 && longitude !=0) {
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minLatitude = (minLatitude > latitude) ? latitude : minLatitude;
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maxLatitude = (maxLatitude < latitude) ? latitude : maxLatitude;
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minLongitude = (minLongitude > longitude) ? longitude : minLongitude;
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maxLongitude = (maxLongitude < longitude) ? longitude : maxLongitude;
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mPoints.add(new Point(latitude, longitude));
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}
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return new MidPoint(new GeoPoint((maxLatitude + minLatitude)/2, (maxLongitude + minLongitude)/2 ), minLatitude, minLongitude, maxLatitude, maxLongitude);
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}
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/**
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* converts radians to bearing
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* @param rad
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* @return bearing
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* @author Google Inc.
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*/
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public static double radToBearing(double rad) {
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return (Math.toDegrees(rad) + 360) % 360;
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}
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} |