LiXiaoqi/minmea
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

README.md: reflect the API changes

Browse Source
This commit is contained in:
Kosma Moczek 2014-04-27 16:44:56 +02:00
parent e510d9912e
commit a5f67aa500
1 changed files with 23 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
README.md
View File

@ -26,22 +26,22 @@ Adding support for more sentences is trivial; see ``minmea.c`` source.
## Fractional number format ## Fractional number format
Internally, minmea stores fractional numbers as pairs of two integers: ``(value, scale)``. Internally, minmea stores fractional numbers as pairs of two integers: ``{value, scale}``.
For example, a value of ``"-123.456"`` would be parsed as ``(-123456, 1000)``. As this For example, a value of ``"-123.456"`` would be parsed as ``{-123456, 1000}``. As this
format is quite unwieldy, minmea provides the following convenience macros for converting format is quite unwieldy, minmea provides the following convenience functions for converting
to either fixed-point or floating-point format: to either fixed-point or floating-point format:
* ``minmea_rescale(-123456, 1000, 10) => -1235`` * ``minmea_rescale({-123456, 1000}, 10) => -1235``
* ``minmea_float(-123456, 1000) => -123.456`` * ``minmea_float({-123456, 1000}) => -123.456``
## Coordinate format ## Coordinate format
NMEA uses the clunky ``DDMM.MMMM`` format which, honestly, is not good in the internet era. NMEA uses the clunky ``DDMM.MMMM`` format which, honestly, is not good in the internet era.
Internally, minmea stores it as a fractional number (see above); for practical uses, Internally, minmea stores it as a fractional number (see above); for practical uses,
the value should be probably converted to the DD.DDDDD floating point format using the the value should be probably converted to the DD.DDDDD floating point format using the
following macro: following function:
* ``minmea_coord(-375165, 100) => -37.860832`` * ``minmea_tocoord({-375165, 100}) => -37.860832``
The library doesn't perform this conversion automatically for the following reasons: The library doesn't perform this conversion automatically for the following reasons:
@ -59,35 +59,35 @@ The library doesn't perform this conversion automatically for the following reas
case MINMEA_SENTENCE_RMC: { case MINMEA_SENTENCE_RMC: {
struct minmea_sentence_rmc frame; struct minmea_sentence_rmc frame;
if (minmea_parse_rmc(&frame, line)) { if (minmea_parse_rmc(&frame, line)) {
printf("+++ raw coordinates and speed: (%d/%d,%d/%d) %d/%d\n", printf("$xxRMC: raw coordinates and speed: (%d/%d,%d/%d) %d/%d\n",
frame.latitude, frame.latitude_scale, frame.latitude.value, frame.latitude.scale,
frame.longitude, frame.longitude_scale, frame.longitude.value, frame.longitude.scale,
frame.speed, frame.speed_scale); frame.speed.value, frame.speed.scale);
printf("+++ fixed-point coordinates and speed scaled to three decimal places: (%d,%d) %d\n", printf("$xxRMC fixed-point coordinates and speed scaled to three decimal places: (%d,%d) %d\n",
minmea_rescale(frame.latitude, frame.latitude_scale, 1000), minmea_rescale(&frame.latitude, 1000),
minmea_rescale(frame.longitude, frame.longitude_scale, 1000), minmea_rescale(&frame.longitude, 1000),
minmea_rescale(frame.speed, frame.speed_scale, 1000)); minmea_rescale(&frame.speed, 1000));
printf("+++ floating point degree coordinates and speed: (%f,%f) %f\n", printf("$xxRMC floating point degree coordinates and speed: (%f,%f) %f\n",
minmea_coord(frame.latitude, frame.latitude_scale), minmea_tocoord(&frame.latitude),
minmea_coord(frame.longitude, frame.longitude_scale), minmea_tocoord(&frame.longitude),
minmea_float(frame.speed, frame.speed_scale)); minmea_tofloat(&frame.speed));
} }
} break; } break;
case MINMEA_SENTENCE_GGA: { case MINMEA_SENTENCE_GGA: {
struct minmea_sentence_gga frame; struct minmea_sentence_gga frame;
if (minmea_parse_gga(&frame, line)) { if (minmea_parse_gga(&frame, line)) {
printf("$GPGGA: fix quality: %d\n", frame.fix_quality); printf("$xxGGA: fix quality: %d\n", frame.fix_quality);
} }
} break; } break;
case MINMEA_SENTENCE_GSV: { case MINMEA_SENTENCE_GSV: {
struct minmea_sentence_gsv frame; struct minmea_sentence_gsv frame;
if (minmea_parse_gsv(&frame, line)) { if (minmea_parse_gsv(&frame, line)) {
printf("$GPGSV: message %d of %d\n", frame.msg_nr, frame.total_msgs); printf("$xxGSV: message %d of %d\n", frame.msg_nr, frame.total_msgs);
printf("$GPGSV: sattelites in view: %d\n", frame.total_sats); printf("$xxGSV: sattelites in view: %d\n", frame.total_sats);
for (int i = 0; i < 4; i++) for (int i = 0; i < 4; i++)
printf("$GPGSV: sat nr %d, elevation: %d, azimuth: %d, snr: %d dbm\n", printf("$xxGSV: sat nr %d, elevation: %d, azimuth: %d, snr: %d dbm\n",
frame.sats[i].nr, frame.sats[i].nr,
frame.sats[i].elevation, frame.sats[i].elevation,
frame.sats[i].azimuth, frame.sats[i].azimuth,