//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2013 John Langner, WB2OSZ
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see .
//
/*------------------------------------------------------------------
*
* Module: latlong.c
*
* Purpose: Various functions for dealing with latitude and longitude.
*
* Description: Originally, these were scattered around in many places.
* Over time they might all be gathered into one place
* for consistency, reuse, and easier maintenance.
*
*---------------------------------------------------------------*/
#include
#include
#include
#include
#include
#include
#include
#include
#include "direwolf.h"
#include "latlong.h"
#include "textcolor.h"
/*------------------------------------------------------------------
*
* Name: latitude_to_str
*
* Purpose: Convert numeric latitude to string for transmission.
*
* Inputs: dlat - Floating point degrees.
* ambiguity - If 1, 2, 3, or 4, blank out that many trailing digits.
*
* Outputs: slat - String in format ddmm.mm[NS]
*
* Returns: None
*
*----------------------------------------------------------------*/
void latitude_to_str (double dlat, int ambiguity, char *slat)
{
char hemi; /* Hemisphere: N or S */
int ideg; /* whole number of degrees. */
double dmin; /* Minutes after removing degrees. */
char smin[8]; /* Minutes in format mm.mm */
if (dlat < -90.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Latitude is less than -90. Changing to -90.n");
dlat = -90.;
}
if (dlat > 90.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Latitude is greater than 90. Changing to 90.n");
dlat = 90.;
}
if (dlat < 0) {
dlat = (- dlat);
hemi = 'S';
}
else {
hemi = 'N';
}
ideg = (int)dlat;
dmin = (dlat - ideg) * 60.;
sprintf (smin, "%05.2f", dmin);
/* Due to roundoff, 59.9999 could come out as "60.00" */
if (smin[0] == '6') {
smin[0] = '0';
ideg++;
}
sprintf (slat, "%02d%s%c", ideg, smin, hemi);
if (ambiguity >= 1) {
slat[6] = ' ';
if (ambiguity >= 2) {
slat[5] = ' ';
if (ambiguity >= 3) {
slat[3] = ' ';
if (ambiguity >= 4) {
slat[2] = ' ';
}
}
}
}
} /* end latitude_to_str */
/*------------------------------------------------------------------
*
* Name: longitude_to_str
*
* Purpose: Convert numeric longitude to string for transmission.
*
* Inputs: dlong - Floating point degrees.
* ambiguity - If 1, 2, 3, or 4, blank out that many trailing digits.
*
* Outputs: slat - String in format dddmm.mm[NS]
*
* Returns: None
*
*----------------------------------------------------------------*/
void longitude_to_str (double dlong, int ambiguity, char *slong)
{
char hemi; /* Hemisphere: N or S */
int ideg; /* whole number of degrees. */
double dmin; /* Minutes after removing degrees. */
char smin[8]; /* Minutes in format mm.mm */
if (dlong < -180.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Longitude is less than -180. Changing to -180.n");
dlong = -180.;
}
if (dlong > 180.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Longitude is greater than 180. Changing to 180.n");
dlong = 180.;
}
if (dlong < 0) {
dlong = (- dlong);
hemi = 'W';
}
else {
hemi = 'E';
}
ideg = (int)dlong;
dmin = (dlong - ideg) * 60.;
sprintf (smin, "%05.2f", dmin);
/* Due to roundoff, 59.9999 could come out as "60.00" */
if (smin[0] == '6') {
smin[0] = '0';
ideg++;
}
sprintf (slong, "%03d%s%c", ideg, smin, hemi);
/*
* The spec says position ambiguity in latitude also
* applies to longitude automatically.
* Blanking longitude digits is not necessary but I do it
* because it makes things clearer.
*/
if (ambiguity >= 1) {
slong[7] = ' ';
if (ambiguity >= 2) {
slong[6] = ' ';
if (ambiguity >= 3) {
slong[4] = ' ';
if (ambiguity >= 4) {
slong[3] = ' ';
}
}
}
}
} /* end longitude_to_str */
/*------------------------------------------------------------------
*
* Name: latitude_to_comp_str
*
* Purpose: Convert numeric latitude to compressed string for transmission.
*
* Inputs: dlat - Floating point degrees.
*
* Outputs: slat - String in format yyyy.
*
*----------------------------------------------------------------*/
void latitude_to_comp_str (double dlat, char *clat)
{
int y, y0, y1, y2, y3;
if (dlat < -90.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Latitude is less than -90. Changing to -90.n");
dlat = -90.;
}
if (dlat > 90.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Latitude is greater than 90. Changing to 90.n");
dlat = 90.;
}
y = (int)round(380926. * (90. - dlat));
y0 = y / (91*91*91);
y -= y0 * (91*91*91);
y1 = y / (91*91);
y -= y1 * (91*91);
y2 = y / (91);
y -= y2 * (91);
y3 = y;
clat[0] = y0 + 33;
clat[1] = y1 + 33;
clat[2] = y2 + 33;
clat[3] = y3 + 33;
}
/*------------------------------------------------------------------
*
* Name: longitude_to_comp_str
*
* Purpose: Convert numeric longitude to compressed string for transmission.
*
* Inputs: dlong - Floating point degrees.
*
* Outputs: slat - String in format xxxx.
*
*----------------------------------------------------------------*/
void longitude_to_comp_str (double dlong, char *clon)
{
int x, x0, x1, x2, x3;
if (dlong < -180.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Longitude is less than -180. Changing to -180.n");
dlong = -180.;
}
if (dlong > 180.) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Longitude is greater than 180. Changing to 180.n");
dlong = 180.;
}
x = (int)round(190463. * (180. + dlong));
x0 = x / (91*91*91);
x -= x0 * (91*91*91);
x1 = x / (91*91);
x -= x1 * (91*91);
x2 = x / (91);
x -= x2 * (91);
x3 = x;
clon[0] = x0 + 33;
clon[1] = x1 + 33;
clon[2] = x2 + 33;
clon[3] = x3 + 33;
}