Now drawing path segments > 1 arc minute as great circle curves instead of rhumb lines

gpxsee.pro

@@ -141,7 +141,8 @@ HEADERS += src/config.h \
     src/data/locparser.h \
     src/data/slfparser.h \
     src/map/geotiffmap.h \
-    src/map/image.h
+    src/map/image.h \
+    src/common/greatcircle.h
 SOURCES += src/main.cpp \
     src/common/coordinates.cpp \
     src/common/rectc.cpp \
@@ -246,7 +247,8 @@ SOURCES += src/main.cpp \
     src/data/locparser.cpp \
     src/data/slfparser.cpp \
     src/map/geotiffmap.cpp \
-    src/map/image.cpp
+    src/map/image.cpp \
+    src/common/greatcircle.cpp
 
 RESOURCES += gpxsee.qrc
 TRANSLATIONS = lang/gpxsee_cs.ts \

src/GUI/pathitem.cpp

@@ -2,6 +2,7 @@
 #include <QApplication>
 #include <QCursor>
 #include <QPainter>
+#include "common/greatcircle.h"
 #include "map/map.h"
 #include "tooltip.h"
 #include "nicenum.h"
@@ -44,8 +45,27 @@ void PathItem::updatePainterPath(Map *map)
 	_painterPath = QPainterPath();
 
 	_painterPath.moveTo(map->ll2xy(_path.first().coordinates()));
-	for (int i = 1; i < _path.size(); i++)
+	for (int i = 1; i < _path.size(); i++) {
-		_painterPath.lineTo(map->ll2xy(_path.at(i).coordinates()));
+		Coordinates c1(_path.at(i-1).coordinates());
+		Coordinates c2(_path.at(i).coordinates());
+		unsigned n = qAbs(c1.lon() - c2.lon());
+
+		if (n) {
+			if (n > 180)
+				n = n - 180;
+			double prev = c1.lon();
+			for (unsigned j = 1; j <= n * 60; j++) {
+				Coordinates c(GreatCircle::pointAt(c1, c2, j/(n * 60.0)));
+				double current = c.lon();
+				if (fabs(current - prev) > 180.0)
+					_painterPath.moveTo(map->ll2xy(c));
+				else
+					_painterPath.lineTo(map->ll2xy(c));
+				prev = current;
+			}
+		} else
+			_painterPath.lineTo(map->ll2xy(c2));
+	}
 }
 
 void PathItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
@@ -141,19 +161,23 @@ QPointF PathItem::position(qreal x) const
 			return _map->ll2xy(_path.at(mid).coordinates());
 	}
 
-	QLineF l;
+	Coordinates c1, c2;
 	qreal p1, p2;
+
 	if (_path.at(mid).distance() < x) {
-		l = QLineF(_map->ll2xy(_path.at(mid).coordinates()),
+		c1 = _path.at(mid).coordinates(); c2 = _path.at(mid+1).coordinates();
-		  _map->ll2xy(_path.at(mid+1).coordinates()));
 		p1 = _path.at(mid).distance(); p2 = _path.at(mid+1).distance();
 	} else {
-		l = QLineF(_map->ll2xy(_path.at(mid-1).coordinates()),
+		c1 = _path.at(mid-1).coordinates(); c2 = _path.at(mid).coordinates();
-		  _map->ll2xy(_path.at(mid).coordinates()));
 		p1 = _path.at(mid-1).distance(); p2 = _path.at(mid).distance();
 	}
 
-	return l.pointAt((x - p1) / (p2 - p1));
+	if ((unsigned)qAbs(c1.lon() - c2.lon()))
+		return _map->ll2xy(GreatCircle::pointAt(c1, c2, (x - p1) / (p2 - p1)));
+	else {
+		QLineF l(_map->ll2xy(c1), _map->ll2xy(c2));
+		return l.pointAt((x - p1) / (p2 - p1));
+	}
 }
 
 void PathItem::moveMarker(qreal distance)

src/common/greatcircle.cpp

@@ -0,0 +1,23 @@
+#include "greatcircle.h"
+
+Coordinates GreatCircle::pointAt(const Coordinates &c1, const Coordinates &c2,
+  double f)
+{
+	double lat1 = deg2rad(c1.lat());
+	double lon1 = deg2rad(c1.lon());
+	double lat2 = deg2rad(c2.lat());
+	double lon2 = deg2rad(c2.lon());
+
+	double cosLat1 = cos(lat1);
+	double cosLat2 = cos(lat2);
+	double d = 2 * asin(sqrt(pow((sin((lat1 - lat2) / 2)), 2) + cosLat1
+	  * cosLat2 * pow(sin((lon1 - lon2) / 2), 2)));
+	double sinD = sin(d);
+	double A = sin((1.0-f)*d) / sinD;
+	double B = sin(f*d) / sinD;
+	double x = A * cosLat1 * cos(lon1) + B * cosLat2 * cos(lon2);
+	double y = A * cosLat1 * sin(lon1) + B * cosLat2 * sin(lon2);
+	double z = A * sin(lat1) + B * sin(lat2);
+
+	return Coordinates(rad2deg(atan2(y, x)), rad2deg(atan2(z, sqrt(x*x + y*y))));
+}

src/common/greatcircle.h

@@ -0,0 +1,11 @@
+#ifndef GREATCIRCLE_H
+#define GREATCIRCLE_H
+
+#include "coordinates.h"
+
+namespace GreatCircle
+{
+	Coordinates pointAt(const Coordinates &c1, const Coordinates &c2, double f);
+}
+
+#endif // GREATCIRCLE_H

src/data/poi.cpp

@@ -1,6 +1,7 @@
 #include <QFile>
 #include <QDir>
 #include "common/rectc.h"
+#include "common/greatcircle.h"
 #include "data.h"
 #include "poi.h"
 
@@ -94,28 +95,6 @@ static bool cb(size_t data, void* context)
 	return true;
 }
 
-static Coordinates intermediate(const Coordinates &c1, const Coordinates &c2,
-  double f)
-{
-	double lat1 = deg2rad(c1.lat());
-	double lon1 = deg2rad(c1.lon());
-	double lat2 = deg2rad(c2.lat());
-	double lon2 = deg2rad(c2.lon());
-
-	double cosLat1 = cos(lat1);
-	double cosLat2 = cos(lat2);
-	double d = 2 * asin(sqrt(pow((sin((lat1 - lat2) / 2)), 2) + cosLat1
-	  * cosLat2 * pow(sin((lon1 - lon2) / 2), 2)));
-	double sinD = sin(d);
-	double A = sin((1.0-f)*d) / sinD;
-	double B = sin(f*d) / sinD;
-	double x = A * cosLat1 * cos(lon1) + B * cosLat2 * cos(lon2);
-	double y = A * cosLat1 * sin(lon1) + B * cosLat2 * sin(lon2);
-	double z = A * sin(lat1) + B * sin(lat2);
-
-	return Coordinates(rad2deg(atan2(y, x)), rad2deg(atan2(z, sqrt(x*x + y*y))));
-}
-
 QList<Waypoint> POI::points(const Path &path) const
 {
 	QList<Waypoint> ret;
@@ -128,8 +107,8 @@ QList<Waypoint> POI::points(const Path &path) const
 		double ds = path.at(i).distance() - path.at(i-1).distance();
 		unsigned n = (unsigned)ceil(ds / _radius);
 		for (unsigned j = 0; j < n; j++) {
-			RectC br(n > 1 ? intermediate(path.at(i-1).coordinates(),
+			RectC br(n > 1 ? GreatCircle::pointAt(path.at(i-1).coordinates(),
-			  path.at(i).coordinates(), (double)j/(double)n)
+			  path.at(i).coordinates(), (double)j/n)
 			  : path.at(i-1).coordinates(), _radius);
 
 			min[0] = br.topLeft().lon();