2 * Copyright (C) 2009 Andy Spencer <spenceal@rose-hulman.edu>
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 3 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 #ifndef __GIS_UTIL_H__
19 #define __GIS_UTIL_H__
21 #define EARTH_R (6371000)
22 #define EARTH_C (2*G_PI*EARTH_R)
32 * rad - Radians, also radius
33 * m - Meters, for earth-based distances
34 * px - Pixels, for screen-based distances
36 * height - Height, the distance above the geoid (ground)
37 * elev - Elevation, the distance above the spheroid
38 * rad - Radius, the distance from the center of the earth
40 * lat - Latitude, amount north-south, -90 (S) .. 90 (N)
41 * lon - Longitude, amount east-west, -180 (W) .. 180 (E)
42 * incl - Inclination, polar equiv of latitude, Pi .. 0
43 * azim - Azimuth, polar equiv of longitude, -Pi .. Pi
45 * x - 0° lon is positive
46 * y - 90° lon is positive
47 * z - North pole is positive
49 * llh - lat,lon,height
57 * lat lon elev -> x y z
58 * lle2xyz: 0.0, 0.0, 0.0 -> 0.0, 0.0, 10.0
59 * lle2xyz: 90.0, 0.0, 0.0 -> 0.0, 10.0, 0.0
60 * lle2xyz: 0.0, 90.0, 0.0 -> 10.0, 0.0, 0.0
62 * x y z -> lat lon elev
63 * xyz2lle: 10.0, 0.0, 0.0 -> 0.0, 90.0, 0.0
64 * xyz2lle: 0.0, 10.0, 0.0 -> 90.0, 0.0, 0.0
65 * xyz2lle: 0.0, 0.0, 10.0 -> 0.0, 0.0, 0.0
68 #define azim2lon(azim) ((azim)*180/G_PI)
69 #define lon2azim(lon) ((lon)*G_PI/180)
70 #define incl2lat(incl) (90-(incl)*180/G_PI)
71 #define lat2incl(lat) ((90-(lat))*G_PI/180)
72 #define rad2elev(rad) ((rad)-EARTH_R)
73 #define elev2rad(elev) ((elev)+EARTH_R)
75 #define deg2rad(deg) (((deg)*G_PI)/180.0)
76 #define rad2deg(rad) (((rad)*180.0)/G_PI)
78 #define FOV_DIST 2000.0
79 #define MPPX(dist) (4*dist/FOV_DIST)
81 void lle2xyz(gdouble lat, gdouble lon, gdouble elev,
82 gdouble *x, gdouble *y, gdouble *z);
84 void xyz2lle(gdouble x, gdouble y, gdouble z,
85 gdouble *lat, gdouble *lon, gdouble *elev);
87 void xyz2ll(gdouble x, gdouble y, gdouble z,
88 gdouble *lat, gdouble *lon);
90 gdouble ll2m(gdouble lon_dist, gdouble lat);
92 gdouble distd(gdouble *a, gdouble *b);
94 gdouble lon_avg(gdouble a, gdouble b);