/*
* Copyright 2015-2017 WorldWind Contributors
*
* Licensed 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.
*/
/**
* @exports ProjectionUPS
*/
define([
'../geom/Angle',
'../error/ArgumentError',
'../projections/GeographicProjection',
'../util/Logger',
'../geom/Sector',
'../geom/Vec3',
'../util/WWMath'
],
function (Angle,
ArgumentError,
GeographicProjection,
Logger,
Sector,
Vec3,
WWMath) {
"use strict";
/**
* Constructs a Uniform Polar Stereographic geographic projection.
* @alias ProjectionUPS
* @constructor
* @augments GeographicProjection
* @classdesc Represents a Uniform Polar Stereographic geographic projection.
* @param {String} pole Indicates the north or south aspect. Specify "North" for the north aspect or "South"
* for the south aspect.
*/
var ProjectionUPS = function (pole) {
// Internal. Intentionally not documented.
this.north = !(pole === "South");
var limits = this.north ? new Sector(0, 90, -180, 180) : new Sector(-90, 0, -180, 180);
GeographicProjection.call(this, "Uniform Polar Stereographic", false, limits);
// Internal. Intentionally not documented. See "pole" property accessor below for public interface.
this._pole = pole;
// Documented in superclass.
this.displayName = this.north ? "North UPS" : "South UPS";
// Internal. Intentionally not documented. See "stateKey" property accessor below for public interface.
this._stateKey = "projection ups " + this._pole + " ";
};
ProjectionUPS.prototype = Object.create(GeographicProjection.prototype);
Object.defineProperties(ProjectionUPS.prototype, {
/**
* Indicates the north or south aspect. Specify "North" or "South".
* @memberof ProjectionPolarEquidistant.prototype
* @type {String}
*/
pole: {
get: function () {
return this._pole;
},
set: function (pole) {
this._pole = pole;
this.north = !(this._pole === "South");
this.projectionLimits = this.north ? new Sector(0, 90, -180, 180) : new Sector(-90, 0, -180, 180);
this._stateKey = "projection ups " + this._pole + " ";
}
},
/**
* A string identifying this projection's current state. Used to compare states during rendering to
* determine whether globe-state dependent cached values must be updated. Applications typically do not
* interact with this property.
* @memberof ProjectionPolarEquidistant.prototype
* @readonly
* @type {String}
*/
stateKey: {
get: function () {
return this._stateKey;
}
}
});
// Documented in base class.
ProjectionUPS.prototype.geographicToCartesian = function (globe, latitude, longitude, elevation,
offset, result) {
if (!globe) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"geographicToCartesian", "missingGlobe"));
}
if (!result) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"geographicToCartesian", "missingResult"));
}
// Formulas taken from "Map Projections -- A Working Manual", Snyder, USGS paper 1395, pg. 161.
if ((this.north && latitude === 90) || (!this.north && latitude === -90)) {
result[0] = 0;
result[1] = 0;
result[2] = elevation;
} else {
var poleFactor = this.north ? 1 : -1,
lat = latitude * Angle.DEGREES_TO_RADIANS,
lon = longitude * Angle.DEGREES_TO_RADIANS,
k0 = 0.994, // standard UPS scale factor -- see above reference pg.157, pp 2.
ecc = Math.sqrt(globe.eccentricitySquared),
s = Math.sqrt(Math.pow(1 + ecc, 1 + ecc) * Math.pow(1 - ecc, 1 - ecc)),
sp, t, r;
if ((this.north && lat < 0) || (!this.north && lat > 0)) {
lat = 0;
}
sp = Math.sin(lat * poleFactor);
t = Math.sqrt(((1 - sp) / (1 + sp)) * Math.pow((1 + ecc * sp) / (1 - ecc * sp), ecc));
r = 2 * globe.equatorialRadius * k0 * t / s;
result[0] = r * Math.sin(lon);
result[1] = -r * Math.cos(lon) * poleFactor;
result[2] = elevation;
}
return result;
};
// Documented in base class.
ProjectionUPS.prototype.geographicToCartesianGrid = function (globe, sector, numLat, numLon,
elevations, referencePoint,
offset, result) {
if (!globe) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"geographicToCartesianGrid", "missingGlobe"));
}
if (!sector) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"geographicToCartesianGrid", "missingSector"));
}
if (!elevations || elevations.length < numLat * numLon) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"geographicToCartesianGrid",
"The specified elevations array is null, undefined or insufficient length"));
}
if (!result) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"geographicToCartesianGrid", "missingResult"));
}
// Formulas taken from "Map Projections -- A Working Manual", Snyder, USGS paper 1395, pg. 161.
var eqr = globe.equatorialRadius,
minLat = sector.minLatitude * Angle.DEGREES_TO_RADIANS,
maxLat = sector.maxLatitude * Angle.DEGREES_TO_RADIANS,
minLon = sector.minLongitude * Angle.DEGREES_TO_RADIANS,
maxLon = sector.maxLongitude * Angle.DEGREES_TO_RADIANS,
deltaLat = (maxLat - minLat) / (numLat > 1 ? numLat - 1 : 1),
deltaLon = (maxLon - minLon) / (numLon > 1 ? numLon - 1 : 1),
minLatLimit = this.projectionLimits.minLatitude * Angle.DEGREES_TO_RADIANS,
maxLatLimit = this.projectionLimits.maxLatitude * Angle.DEGREES_TO_RADIANS,
k0 = 0.994, // standard UPS scale factor -- see above reference pg.157, pp 2.
ecc = Math.sqrt(globe.eccentricitySquared),
s = Math.sqrt(Math.pow(1 + ecc, 1 + ecc) * Math.pow(1 - ecc, 1 - ecc)),
poleFactor = this.north ? 1 : -1,
refPoint = referencePoint ? referencePoint : new Vec3(0, 0, 0),
latIndex, lonIndex,
elevIndex = 0, resultIndex = 0,
lat, lon, clampedLat, sp, t, r;
// Iterate over the latitude and longitude coordinates in the specified sector, computing the Cartesian point
// corresponding to each latitude and longitude.
for (latIndex = 0, lat = minLat; latIndex < numLat; latIndex++, lat += deltaLat) {
if (latIndex === numLat - 1) {
lat = maxLat; // explicitly set the last lat to the max latitude to ensure alignment
}
// Latitude is constant for each row. Values that are a function of latitude can be computed once per row.
clampedLat = WWMath.clamp(lat, minLatLimit, maxLatLimit);
sp = Math.sin(clampedLat * poleFactor);
t = Math.sqrt(((1 - sp) / (1 + sp)) * Math.pow((1 + ecc * sp) / (1 - ecc * sp), ecc));
r = 2 * eqr * k0 * t / s;
for (lonIndex = 0, lon = minLon; lonIndex < numLon; lonIndex++, lon += deltaLon) {
if (lonIndex === numLon - 1) {
lon = maxLon; // explicitly set the last lon to the max longitude to ensure alignment
}
result[resultIndex++] = r * Math.sin(lon) - refPoint[0];
result[resultIndex++] = -r * Math.cos(lon) * poleFactor - refPoint[1];
result[resultIndex++] = elevations[elevIndex++] - refPoint[2];
}
}
return result;
};
// Documented in base class.
ProjectionUPS.prototype.cartesianToGeographic = function (globe, x, y, z, offset, result) {
if (!globe) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"cartesianToGeographic", "missingGlobe"));
}
if (!result) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"cartesianToGeographic", "missingResult"));
}
var lon = Math.atan2(x, y * (this.north ? -1 : 1)),
k0 = 0.994,
ecc = Math.sqrt(globe.eccentricitySquared),
r = Math.sqrt(x * x + y * y),
s = Math.sqrt(Math.pow(1 + ecc, 1 + ecc) * Math.pow(1 - ecc, 1 - ecc)),
t = r * s / (2 * globe.equatorialRadius * k0),
ecc2 = globe.eccentricitySquared,
ecc4 = ecc2 * ecc2,
ecc6 = ecc4 * ecc2,
ecc8 = ecc6 * ecc2,
A = Math.PI / 2 - 2 * Math.atan(t),
B = ecc2 / 2 + 5 * ecc4 / 24 + ecc6 / 12 + 13 * ecc8 / 360,
C = 7 * ecc4 / 48 + 29 * ecc6 / 240 + 811 * ecc8 / 11520,
D = 7 * ecc6 / 120 + 81 * ecc8 / 1120,
E = 4279 * ecc8 / 161280,
Ap = A - C + E,
Bp = B - 3 * D,
Cp = 2 * C - 8 * E,
Dp = 4 * D,
Ep = 8 * E,
s2p = Math.sin(2 * A),
lat = Ap + s2p * (Bp + s2p * (Cp + s2p * (Dp + Ep * s2p)));
lat *= this.north ? 1 : -1;
result.latitude = lat * Angle.RADIANS_TO_DEGREES;
result.longitude = lon * Angle.RADIANS_TO_DEGREES;
result.altitude = z;
return result;
};
// Documented in base class.
ProjectionUPS.prototype.northTangentAtLocation = function (globe, latitude, longitude, result) {
if (!result) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionUPS",
"northTangentAtLocation", "missingResult"));
}
// The north pointing tangent depends on the pole. With the south pole, the north pointing tangent points in
// the same direction as the vector returned by cartesianToGeographic. With the north pole, the north
// pointing tangent has the opposite direction.
result[0] = Math.sin(longitude * Angle.DEGREES_TO_RADIANS) * (this.north ? -1 : 1);
result[1] = Math.cos(longitude * Angle.DEGREES_TO_RADIANS);
result[2] = 0;
return result;
};
// Documented in base class.
ProjectionUPS.prototype.northTangentAtPoint = function (globe, x, y, z, offset, result) {
if (!result) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "ProjectionPolarEquidistant",
"northTangentAtLocation", "missingResult"));
}
var r = Math.sqrt(x * x + y * y);
if (r < 1.0e-4) {
result[0] = 0;
result[1] = 1;
result[2] = 0;
} else {
result[0] = x / r * (this.north ? -1 : 1);
result[1] = y / r * (this.north ? -1 : 1);
result[2] = 0;
}
return result;
};
return ProjectionUPS;
});