src/map/osm.cpp

   1 #include "common/wgs84.h"
   2 #include "osm.h"
   3
   4
   5 #define EPSILON       1e-6
   6
   7 QPointF osm::ll2m(const Coordinates &c)
   8 {
   9         return QPointF(c.lon(), rad2deg(log(tan(M_PI_4 + deg2rad(c.lat())/2.0))));
  10 }
  11
  12 Coordinates osm::m2ll(const QPointF &p)
  13 {
  14         return Coordinates(p.x(), rad2deg(2.0 * atan(exp(deg2rad(p.y()))) - M_PI_2));
  15 }
  16
  17 QPoint osm::mercator2tile(const QPointF &m, int zoom)
  18 {
  19         return QPoint((int)(floor((m.x() + 180.0) / 360.0 * (1<<zoom))),
  20           (int)(floor((1.0 - (m.y() / 180.0)) / 2.0 * (1<<zoom))));
  21 }
  22
  23 qreal osm::zoom2scale(int zoom, int tileSize)
  24 {
  25         return (360.0/(qreal)((1<<zoom) * tileSize));
  26 }
  27
  28 int osm::scale2zoom(qreal scale, int tileSize)
  29 {
  30         return (int)(log2(360.0/(scale * (qreal)tileSize)) + EPSILON);
  31 }
  32
  33 qreal osm::resolution(const QPointF &p, int zoom, int tileSize)
  34 {
  35         qreal scale = zoom2scale(zoom, tileSize);
  36
  37         return (WGS84_RADIUS * 2.0 * M_PI * scale / 360.0
  38           * cos(2.0 * atan(exp(deg2rad(-p.y() * scale))) - M_PI/2));
  39 }