googlesatmapadapter.cpp

/*
*
* This file is part of QMapControl,
* an open-source cross-platform map widget
*
* Copyright (C) 2007 - 2008 Kai Winter
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with QMapControl. If not, see <http://www.gnu.org/licenses/>.
*
* Contact e-mail: kaiwinter@gmx.de
* Program URL   : http://qmapcontrol.sourceforge.net/
*
*/

#include "googlesatmapadapter.h"

#include <math.h>
namespace qmapcontrol
{
    GoogleSatMapAdapter::GoogleSatMapAdapter()
	: TileMapAdapter("kh2.google.com", "/kh?n=404&v=8&t=trtqtt", 256, 0, 19)
    {
        // name = "googlesat";

        numberOfTiles = pow(2, current_zoom+0.0);
        coord_per_x_tile = 360. / numberOfTiles;
        coord_per_y_tile = 180. / numberOfTiles;
    }

    GoogleSatMapAdapter::~GoogleSatMapAdapter()
    {
    }

    QString GoogleSatMapAdapter::getHost() const
    {
        int random = qrand() % 4;
        return QString("kh%1.google.com").arg(random);
    }

    QPoint GoogleSatMapAdapter::coordinateToDisplay(const QPointF& coordinate) const
    {
        //double x = ((coordinate.x()+180)*(tilesize*numberOfTiles/360));
        //double y = (((coordinate.y()*-1)+90)*(tilesize*numberOfTiles/180));

        qreal x = (coordinate.x()+180.) * (numberOfTiles*mytilesize)/360.;		// coord to pixel!
        //double y = -1*(coordinate.y()-90) * (numberOfTiles*tilesize)/180.;	// coord to pixel!
        qreal y = (getMercatorYCoord(coordinate.y())-M_PI) * -1 * (numberOfTiles*mytilesize)/(2*M_PI);	// coord to pixel!
        return QPoint(int(x), int(y));
    }

    QPointF GoogleSatMapAdapter::displayToCoordinate(const QPoint& point) const
    {
        //double lon = ((point.x()/tilesize*numberOfTiles)*360)-180;
        //double lat = (((point.y()/tilesize*numberOfTiles)*180)-90)*-1;

        qreal lon = (point.x()*(360.0/(numberOfTiles*mytilesize)))-180.0;
       // qreal lat = -(point.y()*(180.0/(numberOfTiles*mytilesize)))+90.0;
        // FIXME Looks buggy

        qreal lat = getMercatorLatitude(point.y()*-1*(2*M_PI/(numberOfTiles*mytilesize)) + M_PI);
        //qreal lat = lat *180./M_PI;
        return QPointF(lon, lat);
    }

    qreal GoogleSatMapAdapter::getMercatorLatitude(qreal YCoord) const
    {
        //http://welcome.warnercnr.colostate.edu/class_info/nr502/lg4/projection_mathematics/converting.html
        if (YCoord > M_PI) return 9999.;
        if (YCoord < -M_PI) return -9999.;

        qreal t = atan(exp(YCoord));
        qreal res = (2.*(t))-(M_PI/2.);
        return res;
    }

    qreal GoogleSatMapAdapter::getMercatorYCoord(qreal lati) const
    {
        qreal lat = lati;

        // conversion degre=>radians
        qreal phi = M_PI * lat / 180;

        qreal res;
        //double temp = Math.Tan(Math.PI / 4 - phi / 2);
        //res = Math.Log(temp);
        res = 0.5 * log((1 + sin(phi)) / (1 - sin(phi)));

        return res;
    }

    void GoogleSatMapAdapter::zoom_in()
    {
        current_zoom+=1;
        numberOfTiles = pow(2, current_zoom+0.0);
        coord_per_x_tile = 360. / numberOfTiles;
        coord_per_y_tile = 180. / numberOfTiles;
    }

    void GoogleSatMapAdapter::zoom_out()
    {
        current_zoom-=1;
        numberOfTiles = pow(2, current_zoom+0.0);
        coord_per_x_tile = 360. / numberOfTiles;
        coord_per_y_tile = 180. / numberOfTiles;
    }

    bool GoogleSatMapAdapter::isValid(int x, int y, int z) const
    {
        if ((x>=0 && x < numberOfTiles) && (y>=0 && y < numberOfTiles) && z>=0)
        {
            return true;
        }
        return false;
    }
    QString GoogleSatMapAdapter::query(int i, int j, int z) const
    {
        return getQ(-180+i*coord_per_x_tile,
                    90-(j+1)*coord_per_y_tile, z);
    }

    QString GoogleSatMapAdapter::getQ(qreal longitude, qreal latitude, int zoom) const
    {
        qreal xmin=-180;
        qreal xmax=180;
        qreal ymin=-90;
        qreal ymax=90;

        qreal xmoy=0;
        qreal ymoy=0;
        QString location="t";

        //Google uses a latitude divided by 2;
        qreal halflat = latitude;

        for (int i = 0; i < zoom; i++)
        {
            xmoy = (xmax + xmin) / 2;
            ymoy = (ymax + ymin) / 2;
            if (halflat >= ymoy) //upper part (q or r)
            {
                ymin = ymoy;
                if (longitude < xmoy)
                { /*q*/
                    location+= "q";
                    xmax = xmoy;
                }
                else
                {/*r*/
                    location+= "r";
                    xmin = xmoy;
                }
            }
            else //lower part (t or s)
            {
                ymax = ymoy;
                if (longitude < xmoy)
                { /*t*/

                    location+= "t";
                    xmax = xmoy;
                }
                else
                {/*s*/
                    location+= "s";
                    xmin = xmoy;
                }
            }
        }
        return QString("/kh?n=404&v=24&t=%1").arg(location);
    }
}