functions.h

/************************************************************************************
 * QSlippyMap - Tile based slippery map                                             *
 * Copyright (C) 2017  Michael Carpenter (malcom2073@gmail.com)                     *
 *                                                                                  *
 * This file is a part of QSlippyMap                                                *
 *                                                                                  *
 * QSlippyMap 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, version                    *
 * 2.1 of the License.                                                              *
 *                                                                                  *
 * QSlippyMap 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 this program; if not, write to the Free Software              *
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA   *
 ************************************************************************************/

#ifndef FUNCTIONS_H
#define FUNCTIONS_H
#include <cmath>
int long2tilex(double lon, int z)
{
    return (int)(floor((lon + 180.0) / 360.0 * pow(2.0, z)));
}

int lat2tiley(double lat, int z)
{
    return (int)(floor((1.0 - log( tan(lat * M_PI/180.0) + 1.0 / cos(lat * M_PI/180.0)) / M_PI) / 2.0 * std::pow(2.0, z)));
}

double tilex2long(int x, int z)
{
    return x / pow(2.0, z) * 360.0 - 180;
}

double tiley2lat(int y, int z)
{
    double n = M_PI - 2.0 * M_PI * y / std::pow(2.0, z);
    return 180.0 / M_PI * atan(0.5 * (exp(n) - exp(-n)));
}


#endif // FUNCTIONS_H