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0001 // SPDX-License-Identifier: LGPL-2.1-or-later 0002 // 0003 // SPDX-FileCopyrightText: 2014 Torsten Rahn <rahn@kde.org> 0004 // 0005 0006 // Local 0007 #include "LambertAzimuthalProjection.h" 0008 #include "AbstractProjection_p.h" 0009 0010 #include "MarbleDebug.h" 0011 0012 // Marble 0013 #include "ViewportParams.h" 0014 #include "GeoDataPoint.h" 0015 #include "GeoDataLineString.h" 0016 #include "GeoDataCoordinates.h" 0017 #include "MarbleGlobal.h" 0018 #include "AzimuthalProjection_p.h" 0019 0020 #include <QIcon> 0021 #include <qmath.h> 0022 0023 #define SAFE_DISTANCE 0024 0025 namespace Marble 0026 { 0027 0028 class LambertAzimuthalProjectionPrivate : public AzimuthalProjectionPrivate 0029 { 0030 public: 0031 explicit LambertAzimuthalProjectionPrivate( LambertAzimuthalProjection * parent ); 0032 0033 Q_DECLARE_PUBLIC( LambertAzimuthalProjection ) 0034 }; 0035 0036 LambertAzimuthalProjection::LambertAzimuthalProjection() 0037 : AzimuthalProjection( new LambertAzimuthalProjectionPrivate( this ) ) 0038 { 0039 setMinLat( minValidLat() ); 0040 setMaxLat( maxValidLat() ); 0041 } 0042 0043 LambertAzimuthalProjection::LambertAzimuthalProjection( LambertAzimuthalProjectionPrivate *dd ) 0044 : AzimuthalProjection( dd ) 0045 { 0046 setMinLat( minValidLat() ); 0047 setMaxLat( maxValidLat() ); 0048 } 0049 0050 LambertAzimuthalProjection::~LambertAzimuthalProjection() 0051 { 0052 } 0053 0054 0055 LambertAzimuthalProjectionPrivate::LambertAzimuthalProjectionPrivate( LambertAzimuthalProjection * parent ) 0056 : AzimuthalProjectionPrivate( parent ) 0057 { 0058 } 0059 0060 QString LambertAzimuthalProjection::name() const 0061 { 0062 return QObject::tr( "Lambert Azimuthal Equal-Area" ); 0063 } 0064 0065 QString LambertAzimuthalProjection::description() const 0066 { 0067 return QObject::tr( "<p><b>Lambert Azimuthal Equal-Area Projection</b></p><p>Applications: Used in structural geology to plot directional data.</p>" ); 0068 } 0069 0070 QIcon LambertAzimuthalProjection::icon() const 0071 { 0072 return QIcon(QStringLiteral(":/icons/map-globe.png")); 0073 } 0074 0075 qreal LambertAzimuthalProjection::clippingRadius() const 0076 { 0077 return 1; 0078 } 0079 0080 bool LambertAzimuthalProjection::screenCoordinates( const GeoDataCoordinates &coordinates, 0081 const ViewportParams *viewport, 0082 qreal &x, qreal &y, bool &globeHidesPoint ) const 0083 { 0084 const qreal lambda = coordinates.longitude(); 0085 const qreal phi = coordinates.latitude(); 0086 const qreal lambdaPrime = viewport->centerLongitude(); 0087 const qreal phi1 = viewport->centerLatitude(); 0088 0089 qreal cosC = qSin( phi1 ) * qSin( phi ) + qCos( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime ); 0090 // Prevent division by zero 0091 if (cosC <= 0) { 0092 globeHidesPoint = true; 0093 return false; 0094 } 0095 0096 qreal k = qSqrt(2 / (1 + cosC)); 0097 0098 // Let (x, y) be the position on the screen of the placemark.. 0099 x = ( qCos( phi ) * qSin( lambda - lambdaPrime ) ) * k; 0100 y = ( qCos( phi1 ) * qSin( phi ) - qSin( phi1 ) * qCos( phi ) * qCos( lambda - lambdaPrime ) ) * k; 0101 0102 x *= viewport->radius() / qSqrt(2); 0103 y *= viewport->radius() / qSqrt(2); 0104 0105 const qint64 radius = clippingRadius() * viewport->radius(); 0106 0107 if (x*x + y*y > radius * radius) { 0108 globeHidesPoint = true; 0109 return false; 0110 } 0111 0112 globeHidesPoint = false; 0113 0114 x += viewport->width() / 2; 0115 y = viewport->height() / 2 - y; 0116 0117 // Skip placemarks that are outside the screen area 0118 return !(x < 0 || x >= viewport->width() || y < 0 || y >= viewport->height()); 0119 } 0120 0121 bool LambertAzimuthalProjection::screenCoordinates( const GeoDataCoordinates &coordinates, 0122 const ViewportParams *viewport, 0123 qreal *x, qreal &y, 0124 int &pointRepeatNum, 0125 const QSizeF& size, 0126 bool &globeHidesPoint ) const 0127 { 0128 pointRepeatNum = 0; 0129 globeHidesPoint = false; 0130 0131 bool visible = screenCoordinates( coordinates, viewport, *x, y, globeHidesPoint ); 0132 0133 // Skip placemarks that are outside the screen area 0134 if ( *x + size.width() / 2.0 < 0.0 || *x >= viewport->width() + size.width() / 2.0 0135 || y + size.height() / 2.0 < 0.0 || y >= viewport->height() + size.height() / 2.0 ) 0136 { 0137 return false; 0138 } 0139 0140 // This projection doesn't have any repetitions, 0141 // so the number of screen points referring to the geopoint is one. 0142 pointRepeatNum = 1; 0143 return visible; 0144 } 0145 0146 0147 bool LambertAzimuthalProjection::geoCoordinates( const int x, const int y, 0148 const ViewportParams *viewport, 0149 qreal& lon, qreal& lat, 0150 GeoDataCoordinates::Unit unit ) const 0151 { 0152 const qint64 radius = viewport->radius(); 0153 // Calculate how many degrees are being represented per pixel. 0154 const qreal centerLon = viewport->centerLongitude(); 0155 const qreal centerLat = viewport->centerLatitude(); 0156 const qreal rx = ( - viewport->width() / 2 + x ); 0157 const qreal ry = ( viewport->height() / 2 - y ); 0158 const qreal p = qMax( qSqrt( rx*rx + ry*ry ), qreal(0.0001) ); // ensure we don't divide by zero 0159 0160 // exclude area too far away from map, as it may cause undefined arcsin result 0161 if ( p > (qSqrt(2) * radius) ) { 0162 return false; 0163 } 0164 const qreal c = 2 * qAsin( p / (qSqrt(2) * radius) ); 0165 const qreal sinc = qSin(c); 0166 0167 lon = centerLon + qAtan2( rx*sinc , ( p*qCos( centerLat )*qCos( c ) - ry*qSin( centerLat )*sinc ) ); 0168 0169 while ( lon < -M_PI ) lon += 2 * M_PI; 0170 while ( lon > M_PI ) lon -= 2 * M_PI; 0171 0172 lat = qAsin( qCos(c)*qSin(centerLat) + (ry*sinc*qCos(centerLat))/p ); 0173 0174 if ( unit == GeoDataCoordinates::Degree ) { 0175 lon *= RAD2DEG; 0176 lat *= RAD2DEG; 0177 } 0178 0179 return true; 0180 } 0181 0182 }