1 // magvar.hxx -- magnetic variation wrapper class
3 // Written by Curtis Olson, started July 2000.
5 // Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
29 # error This library requires C++
50 // recalculate the magnetic offset and dip
51 void update( double lon, double lat, double alt_m, double jd );
53 double get_magvar() const { return magvar; }
54 double get_magdip() const { return magdip; }
58 // lookup the magvar for any arbitrary location (doesn't save state
59 // and note that this is a fair amount of cpu work)
60 double sgGetMagVar( double lon, double lat, double alt_m, double jd );