Mega Code Archive
A class to represent a latitude and longitude
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/*
* This file is part of the AusStage Utilities Package
*
* The AusStage Utilities Package is free software: you can redistribute
* it and/or modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* The AusStage Utilities Package is distributed in the hope that it will
* be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the AusStage Utilities Package.
* If not, see <http://www.gnu.org/licenses/>.
*/
//package au.edu.ausstage.utils;
// import additional libraries
import java.text.DecimalFormat;
/**
* A class to represent a latitude and longitude
*/
public class Coordinate implements Comparable<Coordinate>{
// declare private class level variables
private float latitude;
private float longitude;
private DecimalFormat format;
/**
* Constructor for this class
*
* @param latitude a latitude coordinate in decimal notation
* @param longitude a longitude coordinate in decimal notation
*/
public Coordinate(float latitude, float longitude) {
if(CoordinateManager.isValidLatitude(latitude) == true && CoordinateManager.isValidLongitude(longitude) == true) {
this.latitude = latitude;
this.longitude = longitude;
} else {
throw new IllegalArgumentException("The parameters did not pass validation as defined by the CoordinateManager class");
}
this.format = new DecimalFormat("##.######");
}
/*
* get and set methods
*/
public float getLatitude() {
return latitude;
}
public float getLongitude() {
return longitude;
}
public void setLatitude(float latitude) {
if(CoordinateManager.isValidLatitude(latitude) == true) {
this.latitude = latitude;
} else {
throw new IllegalArgumentException("The parameter did not pass validation as defined by the CoordinateManager class");
}
}
public void setLongitude(float longitude) {
if(CoordinateManager.isValidLongitude(longitude) == true) {
this.longitude = longitude;
} else {
throw new IllegalArgumentException("The parameter did not pass validation as defined by the CoordinateManager class");
}
}
public String getLatitudeAsString() {
return format.format(latitude);
}
public String getLongitudeAsString() {
return format.format(longitude);
}
public String toString() {
return format.format(latitude) + ", " + format.format(longitude);
}
/*
* methods required for ordering in collections
* http://java.sun.com/docs/books/tutorial/collections/interfaces/order.html
*/
/**
* A method to determine if one event is the same as another
*
* @param o the object to compare this one to
*
* @return true if they are equal, false if they are not
*/
public boolean equals(Object o) {
// check to make sure the object is an event
if ((o instanceof Coordinate) == false) {
// o is not an event object
return false;
}
// compare these two events
Coordinate c = (Coordinate)o;
// build items for comparison
String me = this.getLatitudeAsString() + this.getLongitudeAsString();
String you = c.getLatitudeAsString() + c.getLongitudeAsString();
return me.equals(you);
} // end equals method
/**
* Overide the default hashcode method
*
* @return a hashcode for this object
*/
public int hashCode() {
String me = this.getLatitudeAsString() + this.getLongitudeAsString();
return 31*me.hashCode();
}
/**
* The compareTo method compares the receiving object with the specified object and returns a
* negative integer, 0, or a positive integer depending on whether the receiving object is
* less than, equal to, or greater than the specified object.
*
* @param c the event to compare this one to
*
* @return an integer indicating comparison result
*/
public int compareTo(Coordinate c) {
String me = this.getLatitudeAsString() + this.getLongitudeAsString();
String you = c.getLatitudeAsString() + c.getLongitudeAsString();
Double meDbl = Double.valueOf(me);
Double youDbl = Double.valueOf(you);
if(meDbl == youDbl) {
return 0;
} else {
Double tmp = Math.floor(meDbl - youDbl);
return tmp.intValue();
}
} // end compareTo method
}
class CoordinateManager {
// declare public constants
/**
* The minimum allowed latitude
*/
public static float MIN_LATITUDE = Float.valueOf("-90.0000");
/**
* The maximum allowed latitude
*/
public static float MAX_LATITUDE = Float.valueOf("90.0000");
/**
* The minimum allowed longitude
*/
public static float MIN_LONGITUDE = Float.valueOf("-180.0000");
/**
* The maximum allowed longitude
*/
public static float MAX_LONGITUDE = Float.valueOf("180.0000");
/**
* The diameter of the Earth used in calculations
*/
public static float EARTH_DIAMETER = Float.valueOf("12756.274");
/**
* A method to validate a latitude value
*
* @param latitude the latitude to check is valid
*
* @return true if, and only if, the latitude is within the MIN and MAX latitude
*/
public static boolean isValidLatitude(float latitude) {
if(latitude >= MIN_LATITUDE && latitude <= MAX_LATITUDE) {
return true;
} else {
return false;
}
}
/**
* A method to validate a longitude value
*
* @param longitude the longitude to check is valid
*
* @return true if, and only if, the longitude is between the MIN and MAX longitude
*/
public static boolean isValidLongitude(float longitude) {
if(longitude >= MIN_LONGITUDE && longitude <= MAX_LONGITUDE) {
return true;
} else {
return false;
}
}
/**
* A private method to calculate the latitude constant
*
* @return a double representing the latitude constant
*/
public static double latitudeConstant() {
return EARTH_DIAMETER * (Math.PI / Float.valueOf("360"));
//return EARTH_DIAMETER * (Float.valueOf("3.14") / Float.valueOf("360"));
}
/**
* A private method to caluclate the longitude constant
*
* @param latitude a latitude coordinate in decimal notation
*
* @return a double representing the longitude constant
*/
public static double longitudeConstant(float latitude) {
//return Math.abs( Math.cos(Math.abs(latitude)));
return EARTH_DIAMETER * Math.PI * Math.abs(Math.cos(Math.abs(latitude))) / Float.valueOf("360");
}
/**
* A method to add distance in a northerly direction to a coordinate
*
* @param latitude a latitude coordinate in decimal notation
* @param longitude a longitude coordinate in decimal notation
* @param distance the distance to add in metres
*
* @return the new coordinate
*/
public static Coordinate addDistanceNorth(float latitude, float longitude, int distance) {
// check on the parameters
if(isValidLatitude(latitude) == false || isValidLongitude(longitude) == false || distance <= 0) {
throw new IllegalArgumentException("All parameters are required and must be valid");
}
// convert the distance from metres to kilometers
float kilometers = distance / new Float(1000);
// calculate the new latitude
double newLat = latitude + (kilometers / latitudeConstant());
return new Coordinate(new Float(newLat).floatValue(), longitude);
}
/**
* A method to add distance in a southerly direction to a coordinate
*
* @param latitude a latitude coordinate in decimal notation
* @param longitude a longitude coordinate in decimal notation
* @param distance the distance to add in metres
*
* @return the new coordinate
*/
public static Coordinate addDistanceSouth(float latitude, float longitude, int distance) {
// check on the parameters
if(isValidLatitude(latitude) == false || isValidLongitude(longitude) == false || distance <= 0) {
throw new IllegalArgumentException("All parameters are required and must be valid");
}
// convert the distance from metres to kilometers
float kilometers = distance / new Float(1000);
// calculate the new latitude
double newLat = latitude - (kilometers / latitudeConstant());
return new Coordinate(new Float(newLat).floatValue(), longitude);
}
/**
* A method to add distance in an easterly direction to a coordinate
*
* @param latitude a latitude coordinate in decimal notation
* @param longitude a longitude coordinate in decimal notation
* @param distance the distance to add in metres
*
* @return the new coordinate
*/
public static Coordinate addDistanceEast(float latitude, float longitude, int distance) {
// check on the parameters
if(isValidLatitude(latitude) == false || isValidLongitude(longitude) == false || distance <= 0) {
throw new IllegalArgumentException("All parameters are required and must be valid");
}
// convert the distance from metres to kilometers
float kilometers = distance / 1000;
// calculate the new longitude
double newLng = longitude + (distance / longitudeConstant(latitude));
return new Coordinate(latitude, new Float(newLng).floatValue());
}
/**
* A method to add distance in an westerly direction to a coordinate
*
* @param latitude a latitude coordinate in decimal notation
* @param longitude a longitude coordinate in decimal notation
* @param distance the distance to add in metres
*
* @return the new coordinate
*/
public static Coordinate addDistanceWest(float latitude, float longitude, int distance) {
// check on the parameters
if(isValidLatitude(latitude) == false || isValidLongitude(longitude) == false || distance <= 0) {
throw new IllegalArgumentException("All parameters are required and must be valid");
}
// convert the distance from metres to kilometers
float kilometers = distance / 1000;
// calculate the new longitude
double newLng = longitude - (distance / longitudeConstant(latitude));
return new Coordinate(latitude, new Float(newLng).floatValue());
}
/**
* A method to build four coordinates representing a bounding box given a start coordinate and a distance
*
* @param latitude a latitude coordinate in decimal notation
* @param longitude a longitude coordinate in decimal notation
* @param distance the distance to add in metres
*
* @return a hashMap representing the bounding box (NE,SE,SW,NW)
*/
public static java.util.HashMap<String, Coordinate> getBoundingBox(float latitude, float longitude, int distance) {
// check on the parameters
if(isValidLatitude(latitude) == false || isValidLongitude(longitude) == false || distance <= 0) {
throw new IllegalArgumentException("All parameters are required and must be valid");
}
// convert the distance from metres to kilometers
float kilometers = distance / 1000;
// declare helper variables
java.util.HashMap<String, Coordinate> boundingBox = new java.util.HashMap<String, Coordinate>();
// calculate the coordinates
Coordinate north = addDistanceNorth(latitude, longitude, distance);
Coordinate south = addDistanceSouth(latitude, longitude, distance);
Coordinate east = addDistanceEast(latitude, longitude, distance);
Coordinate west = addDistanceWest(latitude, longitude, distance);
// build the bounding box object
boundingBox.put("NE", new Coordinate(north.getLatitude(), east.getLongitude()));
boundingBox.put("SE", new Coordinate(south.getLatitude(), east.getLongitude()));
boundingBox.put("SW", new Coordinate(south.getLatitude(), west.getLongitude()));
boundingBox.put("NW", new Coordinate(north.getLatitude(), west.getLongitude()));
// return the bounding box object
return boundingBox;
}
}
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