ais2geojson.c

/* -----------------------------------------------------------------------
   Process AIS messages read from stdin and output JSON structure
   Copyright 2006 by Brian C. Lane
   All Rights Reserved
   ----------------------------------------------------------------------- */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <errno.h>

#include "aismsg_pos.h"

// a buf typically looks like this:
// 2015-09-20T17:00:00;!BSVDM,1,1,,B,13mBwe0P00Pa6:hTHmD>4?vT2<08,0*12
int main(int argc, char *argv[]) {
  char          buf[256];
  aismsg_pos _pos, *pos; pos = &_pos;
  int err = 0;

  char
    config_smi = 1,
    config_nav_status = 1,
    config_pos_acc = 1,
    config_cog = 1,
    config_trueheading = 1,
    config_sog = 1;

  while( !feof(stdin) ) {
    if (fgets( buf, 255, stdin ) == NULL ) break;

    memset(pos, 0, sizeof(aismsg_pos));

    static char* ais;
    static char* prefix;
    // try to split line and find a timestamp prefix
    if((ais = strchr(buf, ';')) != NULL) {
      ais[0] = '\0'; // turn ; into '\0', same buffer nicely becomes two strings
      ais++; // point ais just past the first ;
      pos->ts = buf; // timestamp now points to the buffer beginning (NULL-term were ; was)
    } else { // no ; found on line
      ais = buf;
      prefix = "";
    }

    if((err = buf2pos(ais, pos)) == 0) {
      printf("{\"type\":\"Feature\",");
      printf(
             "" "\"geometry\":{"
             ""   "\"type\":\"Point\","
             ""   "\"coordinates\":[%0.7f,%0.7f]"
             "" "},",
             pos->long_ddd, pos->lat_dd);
      printf(
             "" "\"properties\":{"
             ""   "\"mmsi\":\"%ld\",", pos->userid);
      printf(""   "\"aistype\":%d,", pos->msgid);
      if(config_cog && pos->cog >= 0)   printf("\"cog\":%0.1f,", pos->cog);
      if(config_sog && pos->sog >= 0)   printf("\"sog\":%0.1f,", pos->sog);
      if(config_trueheading && pos->trueheading >= 0 && pos->trueheading < 360) {
          printf("\"trueHeading\":%d,", pos->trueheading);
      }
      if(config_nav_status && pos->nav_status >= 0) {
        printf("\"navStatus\":%d,", pos->nav_status);
      }
      if(config_pos_acc && pos->pos_acc >= 0) {
        printf("\"posAcc\":%d,", pos->pos_acc);
      }
      if(config_smi && pos->smi >= 0)   printf("\"smi\":%d,", pos->smi);
      // always print ts so we don't need to check if we need comma or not
      if(pos->ts == 0) printf("\"ts\":false");
      else {
        // let's try to output ts as an integer first.
        static char* endptr;
        errno = 0;
        long int ts = strtol(pos->ts, &endptr, 10);
        if(errno == 0 && // no errors
           (endptr + 1 == ais)) { // parsed the entire string (pos->ts+strlen(pos->ts) == ais)
          printf("\"ts\":%ld", ts);
        } else {
          printf("\"ts\":\"%s\"", pos->ts);
        }
      }
      printf("}}\n");
    } // else printf("error in buf2aismsg_pos %d\n", err);
  }
  return 0;
}