mirror of https://github.com/wb2osz/direwolf.git
282 lines
6.6 KiB
C
282 lines
6.6 KiB
C
//
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// This file is part of Dire Wolf, an amateur radio packet TNC.
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//
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// Copyright (C) 2013 John Langner, WB2OSZ
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//
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/*------------------------------------------------------------------
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*
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* Module: latlong.c
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*
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* Purpose: Various functions for dealing with latitude and longitude.
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*
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* Description: Originally, these were scattered around in many places.
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* Over time they might all be gathered into one place
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* for consistency, reuse, and easier maintenance.
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*
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*---------------------------------------------------------------*/
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <ctype.h>
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#include <time.h>
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#include <math.h>
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#include <assert.h>
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#include "direwolf.h"
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#include "latlong.h"
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#include "textcolor.h"
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/*------------------------------------------------------------------
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*
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* Name: latitude_to_str
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*
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* Purpose: Convert numeric latitude to string for transmission.
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*
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* Inputs: dlat - Floating point degrees.
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* ambiguity - If 1, 2, 3, or 4, blank out that many trailing digits.
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*
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* Outputs: slat - String in format ddmm.mm[NS]
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*
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* Returns: None
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*
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*----------------------------------------------------------------*/
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void latitude_to_str (double dlat, int ambiguity, char *slat)
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{
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char hemi; /* Hemisphere: N or S */
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int ideg; /* whole number of degrees. */
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double dmin; /* Minutes after removing degrees. */
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char smin[8]; /* Minutes in format mm.mm */
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if (dlat < -90.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Latitude is less than -90. Changing to -90.n");
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dlat = -90.;
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}
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if (dlat > 90.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Latitude is greater than 90. Changing to 90.n");
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dlat = 90.;
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}
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if (dlat < 0) {
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dlat = (- dlat);
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hemi = 'S';
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}
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else {
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hemi = 'N';
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}
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ideg = (int)dlat;
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dmin = (dlat - ideg) * 60.;
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sprintf (smin, "%05.2f", dmin);
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/* Due to roundoff, 59.9999 could come out as "60.00" */
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if (smin[0] == '6') {
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smin[0] = '0';
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ideg++;
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}
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sprintf (slat, "%02d%s%c", ideg, smin, hemi);
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if (ambiguity >= 1) {
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slat[6] = ' ';
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if (ambiguity >= 2) {
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slat[5] = ' ';
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if (ambiguity >= 3) {
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slat[3] = ' ';
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if (ambiguity >= 4) {
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slat[2] = ' ';
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}
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}
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}
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}
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} /* end latitude_to_str */
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/*------------------------------------------------------------------
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*
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* Name: longitude_to_str
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*
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* Purpose: Convert numeric longitude to string for transmission.
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*
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* Inputs: dlong - Floating point degrees.
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* ambiguity - If 1, 2, 3, or 4, blank out that many trailing digits.
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*
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* Outputs: slat - String in format dddmm.mm[NS]
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*
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* Returns: None
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*
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*----------------------------------------------------------------*/
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void longitude_to_str (double dlong, int ambiguity, char *slong)
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{
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char hemi; /* Hemisphere: N or S */
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int ideg; /* whole number of degrees. */
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double dmin; /* Minutes after removing degrees. */
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char smin[8]; /* Minutes in format mm.mm */
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if (dlong < -180.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Longitude is less than -180. Changing to -180.n");
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dlong = -180.;
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}
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if (dlong > 180.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Longitude is greater than 180. Changing to 180.n");
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dlong = 180.;
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}
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if (dlong < 0) {
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dlong = (- dlong);
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hemi = 'W';
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}
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else {
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hemi = 'E';
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}
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ideg = (int)dlong;
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dmin = (dlong - ideg) * 60.;
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sprintf (smin, "%05.2f", dmin);
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/* Due to roundoff, 59.9999 could come out as "60.00" */
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if (smin[0] == '6') {
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smin[0] = '0';
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ideg++;
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}
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sprintf (slong, "%03d%s%c", ideg, smin, hemi);
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/*
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* The spec says position ambiguity in latitude also
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* applies to longitude automatically.
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* Blanking longitude digits is not necessary but I do it
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* because it makes things clearer.
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*/
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if (ambiguity >= 1) {
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slong[7] = ' ';
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if (ambiguity >= 2) {
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slong[6] = ' ';
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if (ambiguity >= 3) {
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slong[4] = ' ';
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if (ambiguity >= 4) {
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slong[3] = ' ';
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}
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}
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}
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}
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} /* end longitude_to_str */
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/*------------------------------------------------------------------
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*
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* Name: latitude_to_comp_str
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*
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* Purpose: Convert numeric latitude to compressed string for transmission.
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*
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* Inputs: dlat - Floating point degrees.
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*
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* Outputs: slat - String in format yyyy.
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*
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*----------------------------------------------------------------*/
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void latitude_to_comp_str (double dlat, char *clat)
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{
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int y, y0, y1, y2, y3;
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if (dlat < -90.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Latitude is less than -90. Changing to -90.n");
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dlat = -90.;
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}
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if (dlat > 90.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Latitude is greater than 90. Changing to 90.n");
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dlat = 90.;
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}
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y = (int)round(380926. * (90. - dlat));
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y0 = y / (91*91*91);
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y -= y0 * (91*91*91);
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y1 = y / (91*91);
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y -= y1 * (91*91);
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y2 = y / (91);
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y -= y2 * (91);
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y3 = y;
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clat[0] = y0 + 33;
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clat[1] = y1 + 33;
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clat[2] = y2 + 33;
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clat[3] = y3 + 33;
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}
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/*------------------------------------------------------------------
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*
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* Name: longitude_to_comp_str
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*
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* Purpose: Convert numeric longitude to compressed string for transmission.
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*
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* Inputs: dlong - Floating point degrees.
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*
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* Outputs: slat - String in format xxxx.
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*
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*----------------------------------------------------------------*/
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void longitude_to_comp_str (double dlong, char *clon)
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{
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int x, x0, x1, x2, x3;
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if (dlong < -180.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Longitude is less than -180. Changing to -180.n");
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dlong = -180.;
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}
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if (dlong > 180.) {
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text_color_set(DW_COLOR_ERROR);
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dw_printf ("Longitude is greater than 180. Changing to 180.n");
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dlong = 180.;
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}
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x = (int)round(190463. * (180. + dlong));
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x0 = x / (91*91*91);
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x -= x0 * (91*91*91);
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x1 = x / (91*91);
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x -= x1 * (91*91);
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x2 = x / (91);
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x -= x2 * (91);
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x3 = x;
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clon[0] = x0 + 33;
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clon[1] = x1 + 33;
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clon[2] = x2 + 33;
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clon[3] = x3 + 33;
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}
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