decode_NEXRAD.c

Go to the documentation of this file.

#include "prototypes.h"
#define TRUE 1
#define FALSE 0
 
char *convertJulianDate();
void msg_exit();
 
main(int argc,char **argv)
   
{
 
 extern int errno;
 FILE *afosfile,*biasfile;
 char ch, prevchar;
 int i,j,n,ihr,iminute,len,len2,k,kk;
 short imin,inc,nrows;
 char clat[9],clon[9],height[7],year[3],month[3],day[3];
 char hour[3],minute[3],radar[4],chour[3],ncharrows;
 char param[7],junk[4],t1[7],t2[7],t3[7];
 char maxval[7],bias[7],error[7],jdate[7],jmin[7];
 char outname[81],biasname[81],sjunk[50],lradar[4];
 char cdate[7];
 div_t time;
 signed char data[300];
 short  nruns,nbytes;
 short xrun,level;
 unsigned char xchar;
 double lat,lon;
 char zchar,ichar;
 struct HRAP hrap;
 struct HRAP irap;
 float cx,cy             ;
 double pw;
 char value[131][131];
 char temp[40];
 char st1dir[80];
 unsigned char cbytes1,cbytes2; 
 FILE *fpout;
 short int maxvalue;
 
 /* open product and find product identifier */
 /* product 81 = hourly precip array         */
 
 afosfile = fopen(argv[1],"rb");
 if(afosfile==NULL) {
 
                    printf("could not open %s\n",argv[1]);
 
                    exit(1);
 
            }
 
 
 fread(data,sizeof(char),300,afosfile);
 
 for(i=0;i<250;i++) {
     
       n=memcmp(&data[i],"HDP",3);
       if(n==0)
              break;
 
     }
 
if(n != 0) {
 
           printf("could not find HDP\n");
 
           exit(1);
 
     }
 
 rewind(afosfile);
     
 data[i+6]=0;         
 strcpy(radar,&data[i+3]);
 
 for (;;)
   {
    n = fscanf(afosfile,"%c",&ch);
    if (n==EOF) msg_exit(argv[1]);
    if (ch == '1' && prevchar == '8') break;
    prevchar=ch;
   }
 
   /* read header block */
 
 n = fscanf(afosfile,"%8s%8s%6s%2s%2s%2s%2s%2s",clat,clon,height,year,month,
     day,hour,minute); 
 
 printf("%s %s %s %s ",radar,clat,clon,height);
 
 if (n==EOF) msg_exit(argv[1]);
 
 n = fscanf(afosfile,"%6s%6s%6s%6s",param,t1,t2,t3);
 if (n==EOF) msg_exit(argv[1]);
 
 for (i=0;i<13;i++)
    fscanf(afosfile,"%6s",param);
 
 n = fscanf(afosfile,"%6s%6s%6s%6s%6s%6s%6s",maxval,bias,error,
       jdate,jmin,param,param);
 if (n==EOF) msg_exit(argv[1]);
 
 strcpy(cdate,convertJulianDate((short)atoi(jdate)));
 
  /* determine product valid time, if not H+00 product quit */
 
 time = div(atoi(jmin),60);
 ihr = time.quot;
 iminute = time.rem;
 
 printf("%s %02d:%02d max=%6s bias=%6s err=%6s\n",
        cdate, ihr, iminute, maxval,bias,error);
 
 if (iminute > 10) {
 
                 printf("%s too old - aborting\n",argv[1]);
 
                 exit(0);
 
           }
 
 sprintf(chour,"%02d",ihr);
 
 fread(sjunk,sizeof(char),11,afosfile);
 
 maxvalue=0;
 
 n = fread(&ncharrows, sizeof(char),1,afosfile);
 
 for (i=0; i<ncharrows; i++)
 
     {
      n = fread(&cbytes1, sizeof(char),1,afosfile);
      n = fread(&cbytes2, sizeof(char),1,afosfile);
      nbytes=cbytes2;
      
      n = fread(data, sizeof(signed char), nbytes-2,afosfile);
 
      if(n != nbytes-2)
 
      {
        printf(" unexpected EOF encoutered -- ");
        printf(" number of bytes expected = %d",nbytes-2);
        printf(" number of bytes found =%d \n",n);
        exit(0);
      }
 
      nruns = (short)((float)(nbytes-2)/2.);
      kk=0;
 
      for (j=0;j<nruns; j++)
     {
      xchar = (unsigned char)data[j*2];
      xrun = (short) xchar;
      level = (short) data[1+j*2];       
 
          for(k=0;k<xrun;k++) {
      
                        if(level > 0) {
                   
                          value[130-i][kk]=(char)level;
                          if(value[130-i][kk] > maxvalue)
                                            maxvalue=value[130-i][kk] ;
                          
                               }
 
                        else
                             value[130-i][kk]=0;
                   
          kk++;
 
         }
 
    }
 
    }
 
  len = strlen("st2_st1");
 
/*  get_apps_defaults("st2_st1",&len,st1dir,&len2); */
 
  strcpy(outname,"/home/sw1/ccp/");
  for(i=0;i<3;i++)
             lradar[i]=tolower(radar[i]);
 
  strcat(outname,lradar);
  errno=access(outname,R_OK);
 
  if(errno != 0)
         mkdir(outname,S_IRWXU | S_IRWXG | S_IRWXO); 
 
  strcat(outname,"/");
  strcat(outname,year);
  errno=access(outname,R_OK);
  if(errno != 0)
         mkdir(outname,S_IRWXU | S_IRWXG | S_IRWXO);
 
  strcat(outname,"/");
  strcat(outname,month);
  errno=access(outname,R_OK);
  if(errno != 0)
         mkdir(outname,S_IRWXU | S_IRWXG | S_IRWXO);
 
  strcat(outname,"/");              
  strcat(outname,day);
  errno=access(outname,R_OK);
  if(errno != 0)
         mkdir(outname,S_IRWXU | S_IRWXG | S_IRWXO);
 
  strcat(outname,"/");
  strcpy(biasname,outname);
  strcat(outname, chour);
  strcat(outname, "Z");
 
 
  fpout=fopen(outname,"wb");
  if(fpout==NULL) {
 
                  printf("could not open %s\n",outname);
 
                  exit(1);
 
        }
 
  fwrite(value,sizeof(char),131*131,fpout);
 
  fclose(fpout);
                                                     
  /* write bias value */
 
  strcat(biasname, "SP");
  strcat(biasname, chour);
  strcat(biasname,"Z");
 
  biasfile = fopen(biasname, "wb");
 
  if(biasfile==NULL) {
 
                     printf("could not open %s\n",biasname);
 
                     exit(1);
 
           }
  fprintf(biasfile,"%.2f\n",atof(bias));
  fclose(biasfile);
 
  printf("decoding of %s finished files %s and %s written\n",argv[1],outname,biasname);
 
  printf("max value is %d\n",maxvalue);
  exit(1);
 
}
 
char *convertJulianDate(jdate)
      short jdate;
{
 char cdate[7];
 int days[]={31,28,31,30,31,30,31,31,30,31,30,31} ;
 int year,month,ndays,date,total,nyear,leap_year;
 total=0;
 for (year=1970;year<2010;year++)
    {
      leap_year=FALSE;
      if (year==1972 || year==1976 || year==1980 ||
           year==1984 || year==1988 || year==1992 || year==1996 ||
           year==2000 || year==2004 || year==2008)
          leap_year=TRUE;
     for (month=0;month<12;month++)
     {
      total = total+days[month];
      if (month==1 && leap_year==TRUE)
          total++;
      if (total >= jdate)
        {
         ndays=days[month];
         if (month==1 && leap_year==TRUE) ndays++;
         date=ndays - (total-jdate);
         month=month+1;
         nyear=year-1900;
         if (year > 2000) nyear=year-2000;
         sprintf(cdate,"%02d%02d%02d",month,date,nyear);
         return cdate;
        }
     }
    }
}
 
void msg_exit(char *name)
{
 printf("Error: end of file reached on %s\n",name);
 exit(1);
}