1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
/****************************************************************************/
/* */
/* ./grid/gridutils.c - Calculate datum variables */
/* */
/* This file is part of gpstrans - a program to communicate with garmin gps */
/* Parts are taken from John F. Waers (jfwaers@csn.net) program MacGPS. */
/* */
/* */
/* Copyright (c) 1995 by Carsten Tschach (tschach@zedat.fu-berlin.de) */
/* */
/* Permission to use, copy, modify, and distribute this software and its */
/* documentation for non-commercial purpose, is hereby granted without fee, */
/* providing that the copyright notice appear in all copies and that both */
/* the copyright notice and this permission notice appear in supporting */
/* documentation. I make no representations about the suitability of this */
/* software for any purpose. It is provides "as is" without express or */
/* implid warranty. */
/* */
/****************************************************************************/
#include "defs.h"
#include "Garmin.h"
#include "Prefs.h"
/****************************************************************************/
/* Calculate datum parameters. */
/****************************************************************************/
void datumParams(short datum, double *a, double *es)
{
extern struct DATUM const gDatum[];
extern struct ELLIPSOID const gEllipsoid[];
extern struct PREFS gPrefs;
double f = 1.0 / gEllipsoid[gDatum[datum].ellipsoid].invf; /* flattening */
*es = 2 * f - f*f; /* eccentricity^2 */
*a = gEllipsoid[gDatum[datum].ellipsoid].a; /* semimajor axis */
}
|
