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Map handles overwritten coordinates
| 1 | /* -*- Mode: C; indent-tabs-mode: nil; c-basic-offset: 4; tab-width: 4 -*- */ |
| 2 | /* vim:set et sw=4 ts=4 cino=t0,(0: */ |
| 3 | /* |
| 4 | * converter.c |
| 5 | * Copyright (C) Marcus Bauer 2008 <marcus.bauer@gmail.com> |
| 6 | * Copyright (C) John Stowers 2008 <john.stowers@gmail.com> |
| 7 | * |
| 8 | * osm-gps-map.c is free software: you can redistribute it and/or modify it |
| 9 | * under the terms of the GNU General Public License as published by the |
| 10 | * Free Software Foundation, either version 3 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * osm-gps-map.c is distributed in the hope that it will be useful, but |
| 14 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| 16 | * See the GNU General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License along |
| 19 | * with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | */ |
| 21 | |
| 22 | #include <math.h> |
| 23 | #include <stdio.h> |
| 24 | |
| 25 | #include "osm-gps-map-types.h" |
| 26 | #include "converter.h" |
| 27 | |
| 28 | |
| 29 | float |
| 30 | deg2rad(float deg) |
| 31 | { |
| 32 | return (deg * M_PI / 180.0); |
| 33 | } |
| 34 | |
| 35 | float |
| 36 | rad2deg(float rad) |
| 37 | { |
| 38 | return (rad / M_PI * 180.0); |
| 39 | } |
| 40 | |
| 41 | |
| 42 | int |
| 43 | lat2pixel( int zoom, |
| 44 | float lat) |
| 45 | { |
| 46 | float lat_m; |
| 47 | int pixel_y; |
| 48 | |
| 49 | lat_m = atanh(sin(lat)); |
| 50 | |
| 51 | /* the formula is |
| 52 | * |
| 53 | * pixel_y = -(2^zoom * TILESIZE * lat_m) / 2PI + (2^zoom * TILESIZE) / 2 |
| 54 | */ |
| 55 | pixel_y = -(int)( (lat_m * TILESIZE * (1 << zoom) ) / (2*M_PI)) + |
| 56 | ((1 << zoom) * (TILESIZE/2) ); |
| 57 | |
| 58 | |
| 59 | return pixel_y; |
| 60 | } |
| 61 | |
| 62 | |
| 63 | int |
| 64 | lon2pixel( int zoom, |
| 65 | float lon) |
| 66 | { |
| 67 | int pixel_x; |
| 68 | int zoom_p = (1<<zoom) * TILESIZE/2; |
| 69 | |
| 70 | /* the formula is |
| 71 | * |
| 72 | * pixel_x = (2^zoom * TILESIZE * lon) / 2PI + (2^zoom * TILESIZE) / 2 |
| 73 | */ |
| 74 | pixel_x = (int)(lon * (zoom_p / M_PI)) + zoom_p; |
| 75 | |
| 76 | return pixel_x; |
| 77 | } |
| 78 | |
| 79 | float |
| 80 | pixel2lon( int zoom, |
| 81 | int pixel_x) |
| 82 | { |
| 83 | float lon; |
| 84 | int zoom_p = (1<<zoom) * TILESIZE/2; |
| 85 | |
| 86 | lon = (pixel_x - zoom_p) / (zoom_p / M_PI) ; |
| 87 | |
| 88 | return lon; |
| 89 | } |
| 90 | |
| 91 | float |
| 92 | pixel2lat( int zoom, |
| 93 | int pixel_y) |
| 94 | { |
| 95 | float lat, lat_m; |
| 96 | |
| 97 | lat_m = (-( pixel_y - ( (1<<zoom) * (TILESIZE/2) ) ) * (2*M_PI)) / |
| 98 | (TILESIZE * (1<<zoom)); |
| 99 | |
| 100 | lat = asin(tanh(lat_m)); |
| 101 | |
| 102 | return lat; |
| 103 | } |