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Bug 550 / 454 work (not yet fully fixed)

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Adding a spherical projection mode which will work at the poles and
+180/-180 line correctly. Not yet enabled since it has other issues to
be addressed.
This commit is contained in:
James Turner 2013-06-30 16:41:05 +01:00
parent 73456b05b4
commit 1924bdfd82
2 changed files with 81 additions and 37 deletions
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110
src/GUI/MapWidget.cxx
View file

@ -387,7 +387,7 @@ MapWidget::MapWidget(int x, int y, int maxX, int maxY) :
_width = maxX - x;
_height = maxY - y;
_hasPanned = false;
_orthoAzimuthProject = false;
_projection = PROJECTION_SAMSON_FLAMSTEED;
_magneticHeadings = false;
MapData::setFont(legendFont);
@ -1621,26 +1621,45 @@ SGVec2d MapWidget::project(const SGGeod& geod) const
SGVec2d p;
double r = earth_radius_lat(geod.getLatitudeRad());
if (_orthoAzimuthProject) {
// http://mathworld.wolfram.com/OrthographicProjection.html
double cosTheta = cos(geod.getLatitudeRad());
double sinDLambda = sin(geod.getLongitudeRad() - _projectionCenter.getLongitudeRad());
double cosDLambda = cos(geod.getLongitudeRad() - _projectionCenter.getLongitudeRad());
double sinTheta1 = sin(_projectionCenter.getLatitudeRad());
double sinTheta = sin(geod.getLatitudeRad());
double cosTheta1 = cos(_projectionCenter.getLatitudeRad());
switch (_projection) {
case PROJECTION_SAMSON_FLAMSTEED:
{
// Sanson-Flamsteed projection, relative to the projection center
double lonDiff = geod.getLongitudeRad() - _projectionCenter.getLongitudeRad(),
latDiff = geod.getLatitudeRad() - _projectionCenter.getLatitudeRad();
p = SGVec2d(cos(geod.getLatitudeRad()) * lonDiff, latDiff) * r * currentScale();
break;
}
case PROJECTION_ORTHO_AZIMUTH:
{
// http://mathworld.wolfram.com/OrthographicProjection.html
double cosTheta = cos(geod.getLatitudeRad());
double sinDLambda = sin(geod.getLongitudeRad() - _projectionCenter.getLongitudeRad());
double cosDLambda = cos(geod.getLongitudeRad() - _projectionCenter.getLongitudeRad());
double sinTheta1 = sin(_projectionCenter.getLatitudeRad());
double sinTheta = sin(geod.getLatitudeRad());
double cosTheta1 = cos(_projectionCenter.getLatitudeRad());
p = SGVec2d(cosTheta * sinDLambda,
(cosTheta1 * sinTheta) - (sinTheta1 * cosTheta * cosDLambda)) * r * currentScale();
break;
}
case PROJECTION_SPHERICAL:
{
SGVec3d cartCenter = SGVec3d::fromGeod(_projectionCenter);
SGVec3d cartPt = SGVec3d::fromGeod(geod) - cartCenter;
// rotate relative to projection center
SGQuatd orient = SGQuatd::fromLonLat(_projectionCenter);
cartPt = orient.rotateBack(cartPt);
return SGVec2d(cartPt.y(), cartPt.x()) * currentScale();
break;
}
} // of projection mode switch
p = SGVec2d(cosTheta * sinDLambda,
(cosTheta1 * sinTheta) - (sinTheta1 * cosTheta * cosDLambda)) * r * currentScale();
} else {
// Sanson-Flamsteed projection, relative to the projection center
double lonDiff = geod.getLongitudeRad() - _projectionCenter.getLongitudeRad(),
latDiff = geod.getLatitudeRad() - _projectionCenter.getLatitudeRad();
p = SGVec2d(cos(geod.getLatitudeRad()) * lonDiff, latDiff) * r * currentScale();
}
// rotate as necessary
double cost = cos(_upHeading * SG_DEGREES_TO_RADIANS),
@ -1658,24 +1677,43 @@ SGGeod MapWidget::unproject(const SGVec2d& p) const
SGVec2d ur(cost * p.x() - sint * p.y(),
sint * p.x() + cost * p.y());
double r = earth_radius_lat(_projectionCenter.getLatitudeRad());
SGVec2d unscaled = ur * (1.0 / (currentScale() * r));
if (_orthoAzimuthProject) {
double phi = length(p);
double c = asin(phi);
double sinTheta1 = sin(_projectionCenter.getLatitudeRad());
double cosTheta1 = cos(_projectionCenter.getLatitudeRad());
double lat = asin(cos(c) * sinTheta1 + ((unscaled.y() * sin(c) * cosTheta1) / phi));
double lon = _projectionCenter.getLongitudeRad() +
switch (_projection) {
case PROJECTION_SAMSON_FLAMSTEED:
{
double r = earth_radius_lat(_projectionCenter.getLatitudeRad());
SGVec2d unscaled = ur * (1.0 / (currentScale() * r));
double lat = unscaled.y() + _projectionCenter.getLatitudeRad();
double lon = (unscaled.x() / cos(lat)) + _projectionCenter.getLongitudeRad();
return SGGeod::fromRad(lon, lat);
}
case PROJECTION_ORTHO_AZIMUTH:
{
double r = earth_radius_lat(_projectionCenter.getLatitudeRad());
SGVec2d unscaled = ur * (1.0 / (currentScale() * r));
double phi = length(p);
double c = asin(phi);
double sinTheta1 = sin(_projectionCenter.getLatitudeRad());
double cosTheta1 = cos(_projectionCenter.getLatitudeRad());
double lat = asin(cos(c) * sinTheta1 + ((unscaled.y() * sin(c) * cosTheta1) / phi));
double lon = _projectionCenter.getLongitudeRad() +
atan((unscaled.x()* sin(c)) / (phi * cosTheta1 * cos(c) - unscaled.y() * sinTheta1 * sin(c)));
return SGGeod::fromRad(lon, lat);
} else {
double lat = unscaled.y() + _projectionCenter.getLatitudeRad();
double lon = (unscaled.x() / cos(lat)) + _projectionCenter.getLongitudeRad();
return SGGeod::fromRad(lon, lat);
}
return SGGeod::fromRad(lon, lat);
}
case PROJECTION_SPHERICAL:
{
SGVec2d unscaled = ur * (1.0 / currentScale());
SGQuatd orient = SGQuatd::fromLonLat(_projectionCenter);
SGVec3d cartCenter = SGVec3d::fromGeod(_projectionCenter);
SGVec3d cartPt = orient.rotate(SGVec3d(unscaled.x(), unscaled.y(), 0.0));
return SGGeod::fromCart(cartPt + cartCenter);
}
} // of projection mode switch
}
double MapWidget::currentScale() const

8
src/GUI/MapWidget.hxx
View file

@ -33,6 +33,12 @@ public:
void setProperty(SGPropertyNode_ptr prop);
private:
enum Projection {
PROJECTION_SAMSON_FLAMSTEED,
PROJECTION_ORTHO_AZIMUTH,
PROJECTION_SPHERICAL
};
int zoom() const;
void handlePan(int x, int y);
@ -103,7 +109,7 @@ private:
bool _hasPanned;
SGGeod _projectionCenter;
bool _orthoAzimuthProject;
Projection _projection;
SGGeod _aircraft;
SGGeod _clickGeod;
SGVec2d _hitLocation;