ucar.unidata.geoloc.projection.LambertAzimuthalEqualArea Maven / Gradle / Ivy
/*
* Copyright 1998-2009 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
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*/
package ucar.unidata.geoloc.projection;
import ucar.nc2.constants.CDM;
import ucar.nc2.constants.CF;
import ucar.unidata.geoloc.*;
/**
* Lambert AzimuthalEqualArea Projection spherical earth.
*
* See John Snyder, Map Projections used by the USGS, Bulletin 1532,
* 2nd edition (1983), p 184
*
* @author Unidata Development Team
* @see Projection
* @see ProjectionImpl
*/
public class LambertAzimuthalEqualArea extends ProjectionImpl {
/**
* constants from Snyder's equations
*/
private double R, sinLat0, cosLat0, lon0Degrees;
private double lat0, lon0; // center lat/lon in degrees
private double falseEasting, falseNorthing;
@Override
public ProjectionImpl constructCopy() {
ProjectionImpl result = new LambertAzimuthalEqualArea(getOriginLat(), getOriginLon(), getFalseEasting(), getFalseNorthing(), R);
result.setDefaultMapArea(defaultMapArea);
result.setName(name);
return result;
}
/**
* Constructor with default parameters
*/
public LambertAzimuthalEqualArea() {
this(40.0, 100.0, 0.0, 0.0, EARTH_RADIUS);
}
/**
* Construct a LambertAzimuthalEqualArea Projection.
*
* @param lat0 lat origin of the coord system on the projection plane
* @param lon0 lon origin of the coord system on the projection plane
* @throws IllegalArgumentException
*/
public LambertAzimuthalEqualArea(double lat0, double lon0) {
this(lat0, lon0, 0.0, 0.0, EARTH_RADIUS);
}
/**
* Construct a LambertAzimuthalEqualArea Projection.
*
* @param lat0 lat origin of the coord system on the projection plane
* @param lon0 lon origin of the coord system on the projection plane
* @param false_easting natural_x_coordinate + false_easting = x coordinate in km
* @param false_northing natural_y_coordinate + false_northing = y coordinate in km
* @param earthRadius radius of the earth in km
* @throws IllegalArgumentException if lat0, par1, par2 = +/-90 deg
*/
public LambertAzimuthalEqualArea(double lat0, double lon0, double false_easting, double false_northing, double earthRadius) {
super("LambertAzimuthalEqualArea", false);
this.lat0 = Math.toRadians(lat0);
lon0Degrees = lon0;
this.lon0 = Math.toRadians(lon0);
R = earthRadius;
if (Double.isNaN(false_easting))
false_easting = 0.0;
if (Double.isNaN(false_northing))
false_northing = 0.0;
this.falseEasting = false_easting;
this.falseNorthing = false_northing;
precalculate();
addParameter(CF.GRID_MAPPING_NAME, CF.LAMBERT_AZIMUTHAL_EQUAL_AREA);
addParameter(CF.LATITUDE_OF_PROJECTION_ORIGIN, lat0);
addParameter(CF.LONGITUDE_OF_PROJECTION_ORIGIN, lon0);
addParameter(CF.EARTH_RADIUS, earthRadius * 1000);
if ((false_easting != 0.0) || (false_northing != 0.0)) {
addParameter(CF.FALSE_EASTING, false_easting);
addParameter(CF.FALSE_NORTHING, false_northing);
addParameter(CDM.UNITS, "km");
}
}
/**
* Precalculate some stuff
*/
private void precalculate() {
sinLat0 = Math.sin(lat0);
cosLat0 = Math.cos(lat0);
lon0Degrees = Math.toDegrees(lon0);
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
LambertAzimuthalEqualArea that = (LambertAzimuthalEqualArea) o;
if (Double.compare(that.R, R) != 0) return false;
if (Double.compare(that.falseEasting, falseEasting) != 0) return false;
if (Double.compare(that.falseNorthing, falseNorthing) != 0) return false;
if (Double.compare(that.lat0, lat0) != 0) return false;
if (Double.compare(that.lon0, lon0) != 0) return false;
if ((defaultMapArea == null) != (that.defaultMapArea == null)) return false; // common case is that these are null
if (defaultMapArea != null && !that.defaultMapArea.equals(defaultMapArea)) return false;
return true;
}
@Override
public int hashCode() {
int result;
long temp;
temp = R != +0.0d ? Double.doubleToLongBits(R) : 0L;
result = (int) (temp ^ (temp >>> 32));
temp = lat0 != +0.0d ? Double.doubleToLongBits(lat0) : 0L;
result = 31 * result + (int) (temp ^ (temp >>> 32));
temp = lon0 != +0.0d ? Double.doubleToLongBits(lon0) : 0L;
result = 31 * result + (int) (temp ^ (temp >>> 32));
temp = falseEasting != +0.0d ? Double.doubleToLongBits(falseEasting) : 0L;
result = 31 * result + (int) (temp ^ (temp >>> 32));
temp = falseNorthing != +0.0d ? Double.doubleToLongBits(falseNorthing) : 0L;
result = 31 * result + (int) (temp ^ (temp >>> 32));
return result;
}
// bean properties
/**
* Get the origin longitude.
*
* @return the origin longitude.
*/
public double getOriginLon() {
return Math.toDegrees(lon0);
}
/**
* Get the origin latitude.
*
* @return the origin latitude.
*/
public double getOriginLat() {
return Math.toDegrees(lat0);
}
/**
* Get the false easting, in km.
*
* @return the false easting.
*/
public double getFalseEasting() {
return falseEasting;
}
/**
* Get the false northing, in km.
*
* @return the false northing.
*/
public double getFalseNorthing() {
return falseNorthing;
}
//////////////////////////////////////////////
// setters for IDV serialization - do not use except for object creating
/**
* Set the origin longitude.
* @param lon the origin longitude.
*/
public void setOriginLon(double lon) {
lon0 = Math.toRadians(lon);
precalculate();
}
/**
* Set the origin latitude.
*
* @param lat the origin latitude.
*/
public void setOriginLat(double lat) {
lat0 = Math.toRadians(lat);
precalculate();
}
/**
* Set the false_easting, in km.
* natural_x_coordinate + false_easting = x coordinate
* @param falseEasting x offset
*/
public void setFalseEasting(double falseEasting) {
this.falseEasting = falseEasting;
}
/**
* Set the false northing, in km.
* natural_y_coordinate + false_northing = y coordinate
* @param falseNorthing y offset
*/
public void setFalseNorthing(double falseNorthing) {
this.falseNorthing = falseNorthing;
}
/////////////////////////////////////////////////////////////////////
/**
* Get the label to be used in the gui for this type of projection
*
* @return Type label
*/
public String getProjectionTypeLabel() {
return "Lambert Azimuth Equal Area";
}
/**
* Create a String of the parameters.
*
* @return a String of the parameters
*/
public String paramsToString() {
return toString();
}
@Override
public String toString() {
return "LambertAzimuthalEqualArea{" +
"falseNorthing=" + falseNorthing +
", falseEasting=" + falseEasting +
", lon0=" + lon0 +
", lat0=" + lat0 +
", R=" + R +
'}';
}
/**
* This returns true when the line between pt1 and pt2 crosses the seam.
* When the cone is flattened, the "seam" is lon0 +- 180.
*
* @param pt1 point 1
* @param pt2 point 2
* @return true when the line between pt1 and pt2 crosses the seam.
*/
public boolean crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) {
// either point is infinite
if (ProjectionPointImpl.isInfinite(pt1)
|| ProjectionPointImpl.isInfinite(pt2)) {
return true;
}
// opposite signed X values, larger then 5000 km
return (pt1.getX() * pt2.getX() < 0)
&& (Math.abs(pt1.getX() - pt2.getX()) > 5000.0);
}
/*MACROBODY
latLonToProj {} {
fromLat = Math.toRadians(fromLat);
double lonDiff =
Math.toRadians(LatLonPointImpl.lonNormal(fromLon-lon0Degrees));
double g =
sinLat0*Math.sin(fromLat) + cosLat0*Math.cos(fromLat)*Math.cos(lonDiff);
double kPrime = Math.sqrt(2/(1 + g));
toX = R*kPrime*Math.cos(fromLat)*Math.sin(lonDiff) + falseEasting;
toY = R*kPrime*(cosLat0*Math.sin(fromLat) - sinLat0*Math.cos(fromLat)*Math.cos(lonDiff)) + falseNorthing;
}
projToLatLon {} {
fromX = fromX - falseEasting;
fromY = fromY - falseNorthing;
double rho = Math.sqrt(fromX*fromX + fromY*fromY);
double c = 2*Math.asin(rho/(2*R));
toLon = lon0;
double temp = 0;
if (Math.abs(rho) > TOLERANCE) {
toLat = Math.asin(Math.cos(c)*sinLat0 + (fromY*Math.sin(c)*cosLat0/rho));
if (Math.abs(lat0 - PI_OVER_4) > TOLERANCE) { // not 90 or -90
temp = rho*cosLat0*Math.cos(c) - fromY*sinLat0*Math.sin(c);
toLon = lon0 + Math.atan(fromX*Math.sin(c)/temp);
} else if (lat0 == PI_OVER_4) {
toLon = lon0 + Math.atan(fromX/-fromY);
temp = -fromY;
} else {
toLon = lon0 + Math.atan(fromX/fromY);
temp = fromY;
}
} else {
toLat = lat0;
}
toLat= Math.toDegrees(toLat);
toLon= Math.toDegrees(toLon);
if (temp < 0) toLon += 180;
toLon= LatLonPointImpl.lonNormal(toLon);
}
MACROBODY*/
/*BEGINGENERATED*/
/*
Note this section has been generated using the convert.tcl script.
This script, run as:
tcl convert.tcl LambertAzimuthalEqualArea.java
takes the actual projection conversion code defined in the MACROBODY
section above and generates the following 6 methods
*/
/**
* Convert a LatLonPoint to projection coordinates
*
* @param latLon convert from these lat, lon coordinates
* @param result the object to write to
* @return the given result
*/
public ProjectionPoint latLonToProj(LatLonPoint latLon,
ProjectionPointImpl result) {
double toX, toY;
double fromLat = latLon.getLatitude();
double fromLon = latLon.getLongitude();
fromLat = Math.toRadians(fromLat);
double lonDiff = Math.toRadians(LatLonPointImpl.lonNormal(fromLon
- lon0Degrees));
double g = sinLat0 * Math.sin(fromLat)
+ cosLat0 * Math.cos(fromLat) * Math.cos(lonDiff);
double kPrime = Math.sqrt(2 / (1 + g));
toX = R * kPrime * Math.cos(fromLat) * Math.sin(lonDiff)
+ falseEasting;
toY = R * kPrime
* (cosLat0 * Math.sin(fromLat)
- sinLat0 * Math.cos(fromLat)
* Math.cos(lonDiff)) + falseNorthing;
result.setLocation(toX, toY);
return result;
}
/**
* Convert projection coordinates to a LatLonPoint
* Note: a new object is not created on each call for the return value.
*
* @param world convert from these projection coordinates
* @param result the object to write to
* @return LatLonPoint convert to these lat/lon coordinates
*/
public LatLonPoint projToLatLon(ProjectionPoint world,
LatLonPointImpl result) {
double toLat, toLon;
double fromX = world.getX();
double fromY = world.getY();
fromX = fromX - falseEasting;
fromY = fromY - falseNorthing;
double rho = Math.sqrt(fromX * fromX + fromY * fromY);
double c = 2 * Math.asin(rho / (2 * R));
toLon = lon0;
double temp = 0;
if (Math.abs(rho) > TOLERANCE) {
toLat = Math.asin(Math.cos(c) * sinLat0
+ (fromY * Math.sin(c) * cosLat0 / rho));
if (Math.abs(lat0 - PI_OVER_4) > TOLERANCE) { // not 90 or -90
temp = rho * cosLat0 * Math.cos(c)
- fromY * sinLat0 * Math.sin(c);
toLon = lon0 + Math.atan(fromX * Math.sin(c) / temp);
} else if (Double.compare(lat0, PI_OVER_4) == 0) {
toLon = lon0 + Math.atan(fromX / -fromY);
temp = -fromY;
} else {
toLon = lon0 + Math.atan(fromX / fromY);
temp = fromY;
}
} else {
toLat = lat0;
}
toLat = Math.toDegrees(toLat);
toLon = Math.toDegrees(toLon);
if (temp < 0) {
toLon += 180;
}
toLon = LatLonPointImpl.lonNormal(toLon);
result.setLatitude(toLat);
result.setLongitude(toLon);
return result;
}
/**
* Convert lat/lon coordinates to projection coordinates.
*
* @param from array of lat/lon coordinates: from[2][n],
* where from[0][i], from[1][i] is the (lat,lon)
* coordinate of the ith point
* @param to resulting array of projection coordinates,
* where to[0][i], to[1][i] is the (x,y) coordinate
* of the ith point
* @param latIndex index of latitude in "from"
* @param lonIndex index of longitude in "from"
* @return the "to" array.
*/
public float[][] latLonToProj(float[][] from, float[][] to, int latIndex,
int lonIndex) {
int cnt = from[0].length;
float[] fromLatA = from[latIndex];
float[] fromLonA = from[lonIndex];
float[] resultXA = to[INDEX_X];
float[] resultYA = to[INDEX_Y];
double toX, toY;
for (int i = 0; i < cnt; i++) {
double fromLat = fromLatA[i];
double fromLon = fromLonA[i];
fromLat = Math.toRadians(fromLat);
double lonDiff = Math.toRadians(LatLonPointImpl.lonNormal(fromLon
- lon0Degrees));
double g = sinLat0 * Math.sin(fromLat)
+ cosLat0 * Math.cos(fromLat) * Math.cos(lonDiff);
double kPrime = Math.sqrt(2 / (1 + g));
toX = R * kPrime * Math.cos(fromLat) * Math.sin(lonDiff)
+ falseEasting;
toY = R * kPrime
* (cosLat0 * Math.sin(fromLat)
- sinLat0 * Math.cos(fromLat)
* Math.cos(lonDiff)) + falseNorthing;
resultXA[i] = (float) toX;
resultYA[i] = (float) toY;
}
return to;
}
/**
* Convert lat/lon coordinates to projection coordinates.
*
* @param from array of lat/lon coordinates: from[2][n], where
* (from[0][i], from[1][i]) is the (lat,lon) coordinate
* of the ith point
* @param to resulting array of projection coordinates: to[2][n]
* where (to[0][i], to[1][i]) is the (x,y) coordinate
* of the ith point
* @return the "to" array
*/
public float[][] projToLatLon(float[][] from, float[][] to) {
int cnt = from[0].length;
float[] fromXA = from[INDEX_X];
float[] fromYA = from[INDEX_Y];
float[] toLatA = to[INDEX_LAT];
float[] toLonA = to[INDEX_LON];
double toLat, toLon;
for (int i = 0; i < cnt; i++) {
double fromX = fromXA[i];
double fromY = fromYA[i];
fromX = fromX - falseEasting;
fromY = fromY - falseNorthing;
double rho = Math.sqrt(fromX * fromX + fromY * fromY);
double c = 2 * Math.asin(rho / (2 * R));
toLon = lon0;
double temp = 0;
if (Math.abs(rho) > TOLERANCE) {
toLat = Math.asin(Math.cos(c) * sinLat0
+ (fromY * Math.sin(c) * cosLat0 / rho));
if (Math.abs(lat0 - PI_OVER_4) > TOLERANCE) { // not 90 or -90
temp = rho * cosLat0 * Math.cos(c)
- fromY * sinLat0 * Math.sin(c);
toLon = lon0 + Math.atan(fromX * Math.sin(c) / temp);
} else if (Double.compare(lat0, PI_OVER_4) == 0) {
toLon = lon0 + Math.atan(fromX / -fromY);
temp = -fromY;
} else {
toLon = lon0 + Math.atan(fromX / fromY);
temp = fromY;
}
} else {
toLat = lat0;
}
toLat = Math.toDegrees(toLat);
toLon = Math.toDegrees(toLon);
if (temp < 0) {
toLon += 180;
}
toLon = LatLonPointImpl.lonNormal(toLon);
toLatA[i] = (float) toLat;
toLonA[i] = (float) toLon;
}
return to;
}
/**
* Convert lat/lon coordinates to projection coordinates.
*
* @param from array of lat/lon coordinates: from[2][n],
* where from[0][i], from[1][i] is the (lat,lon)
* coordinate of the ith point
* @param to resulting array of projection coordinates,
* where to[0][i], to[1][i] is the (x,y) coordinate
* of the ith point
* @param latIndex index of latitude in "from"
* @param lonIndex index of longitude in "from"
* @return the "to" array.
*/
public double[][] latLonToProj(double[][] from, double[][] to,
int latIndex, int lonIndex) {
int cnt = from[0].length;
double[] fromLatA = from[latIndex];
double[] fromLonA = from[lonIndex];
double[] resultXA = to[INDEX_X];
double[] resultYA = to[INDEX_Y];
double toX, toY;
for (int i = 0; i < cnt; i++) {
double fromLat = fromLatA[i];
double fromLon = fromLonA[i];
fromLat = Math.toRadians(fromLat);
double lonDiff = Math.toRadians(LatLonPointImpl.lonNormal(fromLon
- lon0Degrees));
double g = sinLat0 * Math.sin(fromLat)
+ cosLat0 * Math.cos(fromLat) * Math.cos(lonDiff);
double kPrime = Math.sqrt(2 / (1 + g));
toX = R * kPrime * Math.cos(fromLat) * Math.sin(lonDiff)
+ falseEasting;
toY = R * kPrime
* (cosLat0 * Math.sin(fromLat)
- sinLat0 * Math.cos(fromLat)
* Math.cos(lonDiff)) + falseNorthing;
resultXA[i] = toX;
resultYA[i] = toY;
}
return to;
}
/**
* Convert lat/lon coordinates to projection coordinates.
*
* @param from array of lat/lon coordinates: from[2][n], where
* (from[0][i], from[1][i]) is the (lat,lon) coordinate
* of the ith point
* @param to resulting array of projection coordinates: to[2][n]
* where (to[0][i], to[1][i]) is the (x,y) coordinate
* of the ith point
* @return the "to" array
*/
public double[][] projToLatLon(double[][] from, double[][] to) {
int cnt = from[0].length;
double[] fromXA = from[INDEX_X];
double[] fromYA = from[INDEX_Y];
double[] toLatA = to[INDEX_LAT];
double[] toLonA = to[INDEX_LON];
double toLat, toLon;
for (int i = 0; i < cnt; i++) {
double fromX = fromXA[i];
double fromY = fromYA[i];
fromX = fromX - falseEasting;
fromY = fromY - falseNorthing;
double rho = Math.sqrt(fromX * fromX + fromY * fromY);
double c = 2 * Math.asin(rho / (2 * R));
toLon = lon0;
double temp = 0;
if (Math.abs(rho) > TOLERANCE) {
toLat = Math.asin(Math.cos(c) * sinLat0
+ (fromY * Math.sin(c) * cosLat0 / rho));
if (Math.abs(lat0 - PI_OVER_4) > TOLERANCE) { // not 90 or -90
temp = rho * cosLat0 * Math.cos(c)
- fromY * sinLat0 * Math.sin(c);
toLon = lon0 + Math.atan(fromX * Math.sin(c) / temp);
} else if (Double.compare(lat0, PI_OVER_4) == 0) {
toLon = lon0 + Math.atan(fromX / -fromY);
temp = -fromY;
} else {
toLon = lon0 + Math.atan(fromX / fromY);
temp = fromY;
}
} else {
toLat = lat0;
}
toLat = Math.toDegrees(toLat);
toLon = Math.toDegrees(toLon);
if (temp < 0) {
toLon += 180;
}
toLon = LatLonPointImpl.lonNormal(toLon);
toLatA[i] = toLat;
toLonA[i] = toLon;
}
return to;
}
/*ENDGENERATED*/
/**
* Test
*
* @param args not used
*/
public static void main(String[] args) {
LambertAzimuthalEqualArea a = new LambertAzimuthalEqualArea(40, -100);
ProjectionPoint p = a.latLonToProj(-20, 100);
System.out.println("proj point = " + p);
LatLonPoint ll = a.projToLatLon(p);
System.out.println("ll = " + ll);
}
}
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