Esempio n. 1
0
/*--------------------------------------------------------------------------*/
int fits_get_col_minmax(fitsfile *fptr, int colnum, float *datamin, 
                     float *datamax, int *status)
/* 
   Simple utility routine to compute the min and max value in a column
*/
{
    int anynul;
    long nrows, ntodo, firstrow, ii;
    float array[1000], nulval;

    ffgky(fptr, TLONG, "NAXIS2", &nrows, NULL, status); /* no. of rows */

    firstrow = 1;
    nulval = FLOATNULLVALUE;
    *datamin =  9.0E36F;
    *datamax = -9.0E36F;

    while(nrows)
    {
        ntodo = minvalue(nrows, 100);
        ffgcv(fptr, TFLOAT, colnum, firstrow, 1, ntodo, &nulval, array,
              &anynul, status);

        for (ii = 0; ii < ntodo; ii++)
        {
            if (array[ii] != nulval)
            {
                *datamin = minvalue(*datamin, array[ii]);
                *datamax = maxvalue(*datamax, array[ii]);
            }
        }

        nrows -= ntodo;
        firstrow += ntodo;
    }
    return(*status);
}
Esempio n. 2
0
/* process this command */
static int ProcessCmd(char *cmd, char **args, int narg, int node, int tty)
{
  char tbuf[SZ_LINE];
  Finfo finfo, tfinfo;
#if HAVE_CFITSIO
  int xlims[2], ylims[2], bin, got, hdutype, hdunum, ncard;
  int status=0, tstatus=0;
  int dims[2];
  double cens[2];
  char extname[FLEN_CARD];
  char *cols[2] = {"X", "Y"};
  char *ofile="stdout";
  char *section=NULL;
  char *filter=NULL;
  char *slice=NULL;
  char *cardstr=NULL;
  void *tcens=NULL;
  fitsfile *ifptr, *ofptr, *tfptr;
#endif
  switch(*cmd){
  case 'f':
    if( !strcmp(cmd, "fitsFile") ){
      if( narg ){
	if( !(tfinfo=FinfoLookup(args[0])) ){
	  fprintf(stderr, NOIMAGE, args[0]);
	  return 1;
	}
      } else if( !(tfinfo=FinfoGetCurrent()) ){
	fprintf(stderr, NOFINFO, cmd);
	return 1;
      }
      if( tfinfo->fitsfile ){
	if( node ) fprintf(stdout, "fitsFile\r");
	fprintf(stdout, "%s %s\n", tfinfo->fname, tfinfo->fitsfile);
	fflush(stdout);
      }
      return 0;
    }
    break;
    break;
  case 'i':
    if( !strcmp(cmd, "image") ){
      if( !narg ){
	fprintf(stderr, WRONGARGS, cmd, 1, 0);
	return 1;
      }
      /* new image */
      if( !(finfo = FinfoNew(args[0])) ){
	return 1;
      }
      /* make it current */
      FinfoSetCurrent(finfo);
      if( node ) fprintf(stdout, "image\r");
      /* return the FITS file name, if possible */
      fprintf(stdout, "%s %s\n",
	      finfo->fname, finfo->fitsfile ? finfo->fitsfile : "?");
      fflush(stdout);
      return 0;
    } else if( !strcmp(cmd, "image_") ){
      if( !narg ){
	fprintf(stderr, WRONGARGS, cmd, 1, 0);
	return 1;
      }
      /* new image */
      if( !(finfo = FinfoNew(args[0])) ){
	return 1;
      }
      /* make it current */
      FinfoSetCurrent(finfo);
      /* no output! */
      return 0;
    } else if( !strcmp(cmd, "imsection") ){
#if HAVE_CFITSIO
      if( !(finfo=FinfoGetCurrent()) ){
	fprintf(stderr, NOFINFO, cmd);
	return 1;
      }
      if( narg < 2 ){
	fprintf(stderr, WRONGARGS2, cmd, 2);
	return 1;
      }
      ifptr = openFITSFile(finfo->fitsfile, READONLY, EXTLIST, &hdutype,
			   &status);
      if( status ){
	fprintf(stderr, "ERROR: can't open FITS file '%s'\n", finfo->fitsfile);
	return 1;
      }
      /* process args */
      ofile = args[0];
      section = args[1];
      if( narg >= 3 && args[2] ){
	filter = args[2];
      }
      if( narg >= 4 && args[3] ){
	slice = args[3];
      }
      if( !section || !(got = parseSection(ifptr, hdutype, section,
					   xlims, ylims, dims, cens, &bin)) ){
	fprintf(stderr,
		"ERROR: can't parse section for '%s' [%s]\n",
		finfo->fitsfile, (args && args[0]) ? args[0] : "NONE");
	return 1;
      }
      /* output image */
      fits_create_file(&ofptr, ofile, &status);
      if( status ){
	fits_get_errstatus(status, tbuf);
	fprintf(stderr,
		"ERROR: can't open output FITS file to section '%s' [%s]\n",
		finfo->fitsfile, tbuf);
	return 1;
      }
      switch(hdutype){
      case IMAGE_HDU:
	/* image: let cfitsio make a section */
	if( copyImageSection(ifptr, ofptr, dims, cens, bin, slice, &status) ){
	  fits_get_errstatus(status, tbuf);
	  fprintf(stderr,
		  "ERROR: can't copy image section for '%s' [%s]\n",
		  finfo->fitsfile, tbuf);
	  return 1;
	}
	break;
      default:
	/* table: let jsfitsio create an image section by binning the table */
	tfptr = filterTableToImage(ifptr, filter, cols, dims, cens, 1, &status);
	if( status ){
	  fits_get_errstatus(status, tbuf);
	  fprintf(stderr,
		  "ERROR: can't create image from table for '%s' [%s]\n",
		  finfo->fitsfile, tbuf);
	  return 1;
	}
	fits_read_key(tfptr, TSTRING, "CTYPE1", tbuf, NULL, &status);
	if( status == 0 ){
	  if( strstr(tbuf, "--HPX") || strstr(tbuf, "--hpx") ){
	    tcens = cens;
	  }
	}
	status = 0;

	/* copy section to new image */
	if( copyImageSection(tfptr, ofptr, dims, tcens, bin, NULL, &status) ){
	  fits_get_errstatus(status, tbuf);
	  fprintf(stderr,
		  "ERROR: can't copy image section for '%s' [%s]\n",
		  finfo->fitsfile, tbuf);
	  return 1;
	}
	tstatus = 0;
	closeFITSFile(tfptr, &tstatus);
	break;
      }
      if( status ){
	fits_get_errstatus(status, tbuf);
	fprintf(stderr,
		"ERROR: can't create section FITS file for '%s' [%s]\n",
		finfo->fitsfile, tbuf);
	closeFITSFile(ofptr, &status);
	return 1;
      }
      // return a json object with info about original data
      fprintf(stdout, "{\"file\":\"%s\"", finfo->fitsfile);
      fprintf(stdout, ",\"type\":%d", hdutype);
      ffghdn(ifptr, &hdunum);
      fprintf(stdout, ",\"extnum\":%d", hdunum-1);
      tstatus=0;
      ffgky(ifptr, TSTRING, "EXTNAME", extname, NULL, &tstatus);
      if( !tstatus ){
	fprintf(stdout, ",\"extname\":\"%s\"", extname);
      }
      fprintf(stdout, ",\"hdus\":");
      _listhdu(finfo->fitsfile, NULL);
      tstatus=0;
      getHeaderToString(ifptr, &cardstr, &ncard, &tstatus);
      if( cardstr ){
	fprintf(stdout, ",\"ncard\":%d",ncard);
	fprintf(stdout, ",\"cardstr\":\"%s\"",cardstr);
	free(cardstr);
      }
      fprintf(stdout, "}\n");
      fflush(stdout);
      tstatus=0;
      closeFITSFile(ifptr, &tstatus);
      tstatus=0;
      closeFITSFile(ofptr, &tstatus);
      return 0;
#else
      fprintf(stderr,
	      "ERROR: for section support, build js9helper with cfitsio\n");
      return 1;
#endif
    } else if( !strcmp(cmd, "info") ){
      if( tty ){
	if( !(finfo=FinfoGetCurrent()) ){
	  fprintf(stderr, NOFINFO, cmd);
	  return 1;
	}
	/* make sure we have a wcs */
	fprintf(stdout, "fname:\t%s\n", finfo->fname);
	fprintf(stdout, "fits:\t%s\n", finfo->fitsfile?finfo->fitsfile:"N/A");
	fflush(stdout);
      }
      return 0;
    }
    break;
  case 'l':
    /* list all images */
    if( !strcmp(cmd, "list") ){
      FinfoList(stdout);
      return 0;
#if HAVE_CFITSIO
    } else if( !strcmp(cmd, "listhdus") ){
      if( !(finfo=FinfoGetCurrent()) ){
	fprintf(stderr, NOFINFO, cmd);
	return 1;
      }
      _listhdu(finfo->fitsfile, NULL);
      fflush(stdout);
      return 0;
#endif
    }
    break;
  case 's':
    if( !strcmp(cmd, "setDataPath") ){
      if( narg ){
	setenv("JS9_DATAPATH", args[0], 1);
	if( node ) fprintf(stdout, "setDataPath\r");
	fprintf(stdout, "%s\n", getenv("JS9_DATAPATH"));
	fflush(stdout);
      } else {
	fprintf(stderr, WRONGARGS, cmd, 1, 0);
	return 1;
      }
      return 0;
    }
    break;
  case 'u':
    if( !strcmp(cmd, "unimage") ){
      if( !narg ){
	fprintf(stderr, WRONGARGS, cmd, 1, 0);
	return 1;
      }
      /* close this image */
      FinfoFree(args[0]);
      return 0;
    }
    break;
  case '#':
  case '\0':
    return 0;
  default:
    break;
  }
  /* if we reached here, we did not recognize the command */
  fprintf(stderr, "ERROR: unknown command '%s'\n", cmd);
  /* return the news */
  return 2;
}
Esempio n. 3
0
/*--------------------------------------------------------------------------*/
int ffhist(fitsfile **fptr,  /* IO - pointer to table with X and Y cols;    */
                             /*     on output, points to histogram image    */
           char *outfile,    /* I - name for the output histogram file      */
           int imagetype,    /* I - datatype for image: TINT, TSHORT, etc   */
           int naxis,        /* I - number of axes in the histogram image   */
           char colname[4][FLEN_VALUE],   /* I - column names               */
           double *minin,     /* I - minimum histogram value, for each axis */
           double *maxin,     /* I - maximum histogram value, for each axis */
           double *binsizein, /* I - bin size along each axis               */
           char minname[4][FLEN_VALUE], /* I - optional keywords for min    */
           char maxname[4][FLEN_VALUE], /* I - optional keywords for max    */
           char binname[4][FLEN_VALUE], /* I - optional keywords for binsize */
           double weightin,        /* I - binning weighting factor          */
           char wtcol[FLEN_VALUE], /* I - optional keyword or col for weight*/
           int recip,              /* I - use reciprocal of the weight?     */
           char *selectrow,        /* I - optional array (length = no. of   */
                             /* rows in the table).  If the element is true */
                             /* then the corresponding row of the table will*/
                             /* be included in the histogram, otherwise the */
                             /* row will be skipped.  Ingnored if *selectrow*/
                             /* is equal to NULL.                           */
           int *status)
{
    int ii, datatype, repeat, imin, imax, ibin, bitpix, tstatus, use_datamax = 0;
    long haxes[4];
    fitsfile *histptr;
    char errmsg[FLEN_ERRMSG], keyname[FLEN_KEYWORD], card[FLEN_CARD];
    tcolumn *colptr;
    iteratorCol imagepars[1];
    int n_cols = 1, nkeys;
    long  offset = 0;
    long n_per_loop = -1;  /* force whole array to be passed at one time */
    histType histData;    /* Structure holding histogram info for iterator */
    
    float amin[4], amax[4], binsize[4], maxbin[4];
    float datamin = FLOATNULLVALUE, datamax = FLOATNULLVALUE;
    char svalue[FLEN_VALUE];
    double dvalue;
    char cpref[4][FLEN_VALUE];
    char *cptr;

    if (*status > 0)
        return(*status);

    if (naxis > 4)
    {
        ffpmsg("histogram has more than 4 dimensions");
        return(*status = BAD_DIMEN);
    }

    /* reset position to the correct HDU if necessary */
    if ((*fptr)->HDUposition != ((*fptr)->Fptr)->curhdu)
        ffmahd(*fptr, ((*fptr)->HDUposition) + 1, NULL, status);

    histData.tblptr     = *fptr;
    histData.himagetype = imagetype;
    histData.haxis      = naxis;
    histData.rowselector = selectrow;

    if (imagetype == TBYTE)
        bitpix = BYTE_IMG;
    else if (imagetype == TSHORT)
        bitpix = SHORT_IMG;
    else if (imagetype == TINT)
        bitpix = LONG_IMG;
    else if (imagetype == TFLOAT)
        bitpix = FLOAT_IMG;
    else if (imagetype == TDOUBLE)
        bitpix = DOUBLE_IMG;
    else
        return(*status = BAD_DATATYPE);

    /* The CPREF keyword, if it exists, gives the preferred columns. */
    /* Otherwise, assume "X", "Y", "Z", and "T"  */

    tstatus = 0;
    ffgky(*fptr, TSTRING, "CPREF", cpref[0], NULL, &tstatus);

    if (!tstatus)
    {
        /* Preferred column names are given;  separate them */
        cptr = cpref[0];

        /* the first preferred axis... */
        while (*cptr != ',' && *cptr != '\0')
           cptr++;

        if (*cptr != '\0')
        {
           *cptr = '\0';
           cptr++;
           while (*cptr == ' ')
               cptr++;

           strcpy(cpref[1], cptr);
           cptr = cpref[1];

          /* the second preferred axis... */
          while (*cptr != ',' && *cptr != '\0')
             cptr++;

          if (*cptr != '\0')
          {
             *cptr = '\0';
             cptr++;
             while (*cptr == ' ')
                 cptr++;

             strcpy(cpref[2], cptr);
             cptr = cpref[2];

            /* the third preferred axis... */
            while (*cptr != ',' && *cptr != '\0')
               cptr++;

            if (*cptr != '\0')
            {
               *cptr = '\0';
               cptr++;
               while (*cptr == ' ')
                   cptr++;

               strcpy(cpref[3], cptr);

            }
          }
        }
    }

    for (ii = 0; ii < naxis; ii++)
    {

      /* get the min, max, and binsize values from keywords, if specified */

      if (*minname[ii])
      {
         if (ffgky(*fptr, TDOUBLE, minname[ii], &minin[ii], NULL, status) )
         {
             ffpmsg("error reading histogramming minimum keyword");
             ffpmsg(minname[ii]);
             return(*status);
         }
      }

      if (*maxname[ii])
      {
         if (ffgky(*fptr, TDOUBLE, maxname[ii], &maxin[ii], NULL, status) )
         {
             ffpmsg("error reading histogramming maximum keyword");
             ffpmsg(maxname[ii]);
             return(*status);
         }
      }

      if (*binname[ii])
      {
         if (ffgky(*fptr, TDOUBLE, binname[ii], &binsizein[ii], NULL, status) )
         {
             ffpmsg("error reading histogramming binsize keyword");
             ffpmsg(binname[ii]);
             return(*status);
         }
      }

      if (binsizein[ii] == 0.)
      {
        ffpmsg("error: histogram binsize = 0");
        return(*status = ZERO_SCALE);
      }

      if (*colname[ii] == '\0')
      {
         strcpy(colname[ii], cpref[ii]); /* try using the preferred column */
         if (*colname[ii] == '\0')
         {
           if (ii == 0)
              strcpy(colname[ii], "X");
           else if (ii == 1)
              strcpy(colname[ii], "Y");
           else if (ii == 2)
              strcpy(colname[ii], "Z");
           else if (ii == 3)
              strcpy(colname[ii], "T");
         }
      }

      /* get the column number in the table */
      if (ffgcno(*fptr, CASEINSEN, colname[ii], histData.hcolnum+ii, status)
              > 0)
      {
        strcpy(errmsg, "column for histogram axis doesn't exist: ");
        strcat(errmsg, colname[ii]);
        ffpmsg(errmsg);
        return(*status);
      }

      colptr = ((*fptr)->Fptr)->tableptr;
      colptr += (histData.hcolnum[ii] - 1);

      repeat = (int) colptr->trepeat;  /* vector repeat factor of the column */
      if (repeat > 1)
      {
        strcpy(errmsg, "Can't bin a vector column: ");
        strcat(errmsg, colname[ii]);
        ffpmsg(errmsg);
        return(*status = BAD_DATATYPE);
      }

      /* get the datatype of the column */
      fits_get_coltype(*fptr, histData.hcolnum[ii], &datatype,
         NULL, NULL, status);

      if (datatype < 0 || datatype == TSTRING)
      {
        strcpy(errmsg, "Inappropriate datatype; can't bin this column: ");
        strcat(errmsg, colname[ii]);
        ffpmsg(errmsg);
        return(*status = BAD_DATATYPE);
      }

      /* use TLMINn and TLMAXn keyword values if min and max were not given */
      /* else use actual data min and max if TLMINn and TLMAXn don't exist */
 
      if (minin[ii] == DOUBLENULLVALUE)
      {
        ffkeyn("TLMIN", histData.hcolnum[ii], keyname, status);
        if (ffgky(*fptr, TFLOAT, keyname, amin+ii, NULL, status) > 0)
        {
            /* use actual data minimum value for the histogram minimum */
            *status = 0;
            if (fits_get_col_minmax(*fptr, histData.hcolnum[ii], amin+ii, &datamax, status) > 0)
            {
                strcpy(errmsg, "Error calculating datamin and datamax for column: ");
                strcat(errmsg, colname[ii]);
                ffpmsg(errmsg);
                return(*status);
            }
         }
      }
      else
      {
        amin[ii] = (float) minin[ii];
      }

      if (maxin[ii] == DOUBLENULLVALUE)
      {
        ffkeyn("TLMAX", histData.hcolnum[ii], keyname, status);
        if (ffgky(*fptr, TFLOAT, keyname, &amax[ii], NULL, status) > 0)
        {
          *status = 0;
          if(datamax != FLOATNULLVALUE)  /* already computed max value */
          {
             amax[ii] = datamax;
          }
          else
          {
             /* use actual data maximum value for the histogram maximum */
             if (fits_get_col_minmax(*fptr, histData.hcolnum[ii], &datamin, &amax[ii], status) > 0)
             {
                 strcpy(errmsg, "Error calculating datamin and datamax for column: ");
                 strcat(errmsg, colname[ii]);
                 ffpmsg(errmsg);
                 return(*status);
             }
          }
        }
        use_datamax = 1;  /* flag that the max was determined by the data values */
                          /* and not specifically set by the calling program */
      }
      else
      {
        amax[ii] = (float) maxin[ii];
      }

      /* use TDBINn keyword or else 1 if bin size is not given */
      if (binsizein[ii] == DOUBLENULLVALUE)
      {
         tstatus = 0;
         ffkeyn("TDBIN", histData.hcolnum[ii], keyname, &tstatus);

         if (ffgky(*fptr, TDOUBLE, keyname, binsizein + ii, NULL, &tstatus) > 0)
         {
	    /* make at least 10 bins */
            binsizein[ii] = (amax[ii] - amin[ii]) / 10. ;
            if (binsizein[ii] > 1.)
                binsizein[ii] = 1.;  /* use default bin size */
         }
      }

      if ( (amin[ii] > amax[ii] && binsizein[ii] > 0. ) ||
           (amin[ii] < amax[ii] && binsizein[ii] < 0. ) )
          binsize[ii] = (float) -binsizein[ii];  /* reverse the sign of binsize */
      else
          binsize[ii] =  (float) binsizein[ii];  /* binsize has the correct sign */

      ibin = (int) binsize[ii];
      imin = (int) amin[ii];
      imax = (int) amax[ii];

      /* Determine the range and number of bins in the histogram. This  */
      /* depends on whether the input columns are integer or floats, so */
      /* treat each case separately.                                    */

      if (datatype <= TLONG && (float) imin == amin[ii] &&
                               (float) imax == amax[ii] &&
                               (float) ibin == binsize[ii] )
      {
        /* This is an integer column and integer limits were entered. */
        /* Shift the lower and upper histogramming limits by 0.5, so that */
        /* the values fall in the center of the bin, not on the edge. */

        haxes[ii] = (imax - imin) / ibin + 1;  /* last bin may only */
                                               /* be partially full */
        maxbin[ii] = (float) (haxes[ii] + 1.);  /* add 1. instead of .5 to avoid roundoff */

        if (amin[ii] < amax[ii])
        {
          amin[ii] = (float) (amin[ii] - 0.5);
          amax[ii] = (float) (amax[ii] + 0.5);
        }
        else
        {
          amin[ii] = (float) (amin[ii] + 0.5);
          amax[ii] = (float) (amax[ii] - 0.5);
        }
      }
      else if (use_datamax)  
      {
        /* Either the column datatype and/or the limits are floating point, */
        /* and the histogram limits are being defined by the min and max */
        /* values of the array.  Add 1 to the number of histogram bins to */
        /* make sure that pixels that are equal to the maximum or are */
        /* in the last partial bin are included.  */

        maxbin[ii] = (amax[ii] - amin[ii]) / binsize[ii]; 
        haxes[ii] = (long) (maxbin[ii] + 1);
      }
      else  
      {
        /*  float datatype column and/or limits, and the maximum value to */
        /*  include in the histogram is specified by the calling program. */
        /*  The lower limit is inclusive, but upper limit is exclusive    */
        maxbin[ii] = (amax[ii] - amin[ii]) / binsize[ii];
        haxes[ii] = (long) maxbin[ii];

        if (amin[ii] < amax[ii])
        {
          if (amin[ii] + (haxes[ii] * binsize[ii]) < amax[ii])
            haxes[ii]++;   /* need to include another partial bin */
        }
        else
        {
          if (amin[ii] + (haxes[ii] * binsize[ii]) > amax[ii])
            haxes[ii]++;   /* need to include another partial bin */
        }
      }
    }

       /* get the histogramming weighting factor */
    if (*wtcol)
    {
        /* first, look for a keyword with the weight value */
        if (ffgky(*fptr, TFLOAT, wtcol, &histData.weight, NULL, status) )
        {
            /* not a keyword, so look for column with this name */
            *status = 0;

            /* get the column number in the table */
            if (ffgcno(*fptr, CASEINSEN, wtcol, &histData.wtcolnum, status) > 0)
            {
               ffpmsg(
               "keyword or column for histogram weights doesn't exist: ");
               ffpmsg(wtcol);
               return(*status);
            }

            histData.weight = FLOATNULLVALUE;
        }
    }
    else
        histData.weight = (float) weightin;

    if (histData.weight <= 0. && histData.weight != FLOATNULLVALUE)
    {
        ffpmsg("Illegal histogramming weighting factor <= 0.");
        return(*status = URL_PARSE_ERROR);
    }

    if (recip && histData.weight != FLOATNULLVALUE)
       /* take reciprocal of weight */
       histData.weight = (float) (1.0 / histData.weight);

    histData.wtrecip = recip;
        
    /* size of histogram is now known, so create temp output file */
    if (ffinit(&histptr, outfile, status) > 0)
    {
        ffpmsg("failed to create temp output file for histogram");
        return(*status);
    }

    if (ffcrim(histptr, bitpix, histData.haxis, haxes, status) > 0)
    {
        ffpmsg("failed to create primary array histogram in temp file");
        ffclos(histptr, status);
        return(*status);
    }

    /* copy all non-structural keywords from the table to the image */
    fits_get_hdrspace(*fptr, &nkeys, NULL, status);
    for (ii = 1; ii <= nkeys; ii++)
    {
       fits_read_record(*fptr, ii, card, status);
       if (fits_get_keyclass(card) >= 120)
           fits_write_record(histptr, card, status);
    }           

    /* Set global variables with histogram parameter values.    */
    /* Use separate scalar variables rather than arrays because */
    /* it is more efficient when computing the histogram.       */

    histData.amin1 = amin[0];
    histData.maxbin1 = maxbin[0];
    histData.binsize1 = binsize[0];
    histData.haxis1 = haxes[0];

    if (histData.haxis > 1)
    {
      histData.amin2 = amin[1];
      histData.maxbin2 = maxbin[1];
      histData.binsize2 = binsize[1];
      histData.haxis2 = haxes[1];

      if (histData.haxis > 2)
      {
        histData.amin3 = amin[2];
        histData.maxbin3 = maxbin[2];
        histData.binsize3 = binsize[2];
        histData.haxis3 = haxes[2];

        if (histData.haxis > 3)
        {
          histData.amin4 = amin[3];
          histData.maxbin4 = maxbin[3];
          histData.binsize4 = binsize[3];
          histData.haxis4 = haxes[3];
        }
      }
    }

    /* define parameters of image for the iterator function */
    fits_iter_set_file(imagepars, histptr);        /* pointer to image */
    fits_iter_set_datatype(imagepars, imagetype);  /* image datatype   */
    fits_iter_set_iotype(imagepars, OutputCol);    /* image is output  */

    /* call the iterator function to write out the histogram image */
    if (fits_iterate_data(n_cols, imagepars, offset, n_per_loop,
                          ffwritehisto, (void*)&histData, status) )
         return(*status);

    /* write the World Coordinate System (WCS) keywords */
    /* create default values if WCS keywords are not present in the table */
    for (ii = 0; ii < histData.haxis; ii++)
    {
     /*  CTYPEn  */
       tstatus = 0;
       ffkeyn("TCTYP", histData.hcolnum[ii], keyname, &tstatus);
       ffgky(*fptr, TSTRING, keyname, svalue, NULL, &tstatus);
       if (tstatus)
       {               /* just use column name as the type */
          tstatus = 0;
          ffkeyn("TTYPE", histData.hcolnum[ii], keyname, &tstatus);
          ffgky(*fptr, TSTRING, keyname, svalue, NULL, &tstatus);
       }

       if (!tstatus)
       {
        ffkeyn("CTYPE", ii + 1, keyname, &tstatus);
        ffpky(histptr, TSTRING, keyname, svalue, "Coordinate Type", &tstatus);
       }
       else
          tstatus = 0;

     /*  CUNITn  */
       ffkeyn("TCUNI", histData.hcolnum[ii], keyname, &tstatus);
       ffgky(*fptr, TSTRING, keyname, svalue, NULL, &tstatus);
       if (tstatus)
       {         /* use the column units */
          tstatus = 0;
          ffkeyn("TUNIT", histData.hcolnum[ii], keyname, &tstatus);
          ffgky(*fptr, TSTRING, keyname, svalue, NULL, &tstatus);
       }

       if (!tstatus)
       {
        ffkeyn("CUNIT", ii + 1, keyname, &tstatus);
        ffpky(histptr, TSTRING, keyname, svalue, "Coordinate Units", &tstatus);
       }
       else
         tstatus = 0;

     /*  CRPIXn  - Reference Pixel  */
       ffkeyn("TCRPX", histData.hcolnum[ii], keyname, &tstatus);
       ffgky(*fptr, TDOUBLE, keyname, &dvalue, NULL, &tstatus);
       if (tstatus)
       {
         dvalue = 1.0; /* choose first pixel in new image as ref. pix. */
         tstatus = 0;
       }
       else
       {
           /* calculate locate of the ref. pix. in the new image */
           dvalue = (dvalue - amin[ii]) / binsize[ii] + .5;
       }

       ffkeyn("CRPIX", ii + 1, keyname, &tstatus);
       ffpky(histptr, TDOUBLE, keyname, &dvalue, "Reference Pixel", &tstatus);

     /*  CRVALn - Value at the location of the reference pixel */
       ffkeyn("TCRVL", histData.hcolnum[ii], keyname, &tstatus);
       ffgky(*fptr, TDOUBLE, keyname, &dvalue, NULL, &tstatus);
       if (tstatus)
       {
         /* calculate value at ref. pix. location (at center of 1st pixel) */
         dvalue = amin[ii] + binsize[ii]/2.;
         tstatus = 0;
       }

       ffkeyn("CRVAL", ii + 1, keyname, &tstatus);
       ffpky(histptr, TDOUBLE, keyname, &dvalue, "Reference Value", &tstatus);

     /*  CDELTn - unit size of pixels  */
       ffkeyn("TCDLT", histData.hcolnum[ii], keyname, &tstatus);
       ffgky(*fptr, TDOUBLE, keyname, &dvalue, NULL, &tstatus);
       if (tstatus)
       {
         dvalue = 1.0;  /* use default pixel size */
         tstatus = 0;
       }

       dvalue = dvalue * binsize[ii];
       ffkeyn("CDELT", ii + 1, keyname, &tstatus);
       ffpky(histptr, TDOUBLE, keyname, &dvalue, "Pixel size", &tstatus);

     /*  CROTAn - Rotation angle (degrees CCW)  */
     /*  There should only be a CROTA2 keyword, and only for 2+ D images */
       if (ii == 1)
       {
         ffkeyn("TCROT", histData.hcolnum[ii], keyname, &tstatus);
         ffgky(*fptr, TDOUBLE, keyname, &dvalue, NULL, &tstatus);
         if (!tstatus && dvalue != 0.)  /* only write keyword if angle != 0 */
         {
           ffkeyn("CROTA", ii + 1, keyname, &tstatus);
           ffpky(histptr, TDOUBLE, keyname, &dvalue,
                 "Rotation angle", &tstatus);
         }
         else
         {
            /* didn't find CROTA for the 2nd axis, so look for one */
            /* on the first axis */
           tstatus = 0;
           ffkeyn("TCROT", histData.hcolnum[0], keyname, &tstatus);
           ffgky(*fptr, TDOUBLE, keyname, &dvalue, NULL, &tstatus);
           if (!tstatus && dvalue != 0.)  /* only write keyword if angle != 0 */
           {
             dvalue *= -1.;   /* negate the value, because mirror image */
             ffkeyn("CROTA", ii + 1, keyname, &tstatus);
             ffpky(histptr, TDOUBLE, keyname, &dvalue,
                   "Rotation angle", &tstatus);
           }
         }
       }
    }

    /* convert any TPn_k keywords to PCi_j; the value remains unchanged */
    /* also convert any TCn_k to CDi_j; the value is modified by n binning size */
    /* This is a bit of a kludge, and only works for 2D WCS */

    if (histData.haxis == 2) {

      /* PC1_1 */
      tstatus = 0;
      ffkeyn("TP", histData.hcolnum[0], card, &tstatus);
      strcat(card,"_");
      ffkeyn(card, histData.hcolnum[0], keyname, &tstatus);
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) 
         ffpky(histptr, TDOUBLE, "PC1_1", &dvalue, card, &tstatus);

      tstatus = 0;
      keyname[1] = 'C';
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) {
         dvalue *=  binsize[0];
         ffpky(histptr, TDOUBLE, "CD1_1", &dvalue, card, &tstatus);
      }

      /* PC1_2 */
      tstatus = 0;
      ffkeyn("TP", histData.hcolnum[0], card, &tstatus);
      strcat(card,"_");
      ffkeyn(card, histData.hcolnum[1], keyname, &tstatus);
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) 
         ffpky(histptr, TDOUBLE, "PC1_2", &dvalue, card, &tstatus);
 
      tstatus = 0;
      keyname[1] = 'C';
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) {
        dvalue *=  binsize[0];
        ffpky(histptr, TDOUBLE, "CD1_2", &dvalue, card, &tstatus);
      }
       
      /* PC2_1 */
      tstatus = 0;
      ffkeyn("TP", histData.hcolnum[1], card, &tstatus);
      strcat(card,"_");
      ffkeyn(card, histData.hcolnum[0], keyname, &tstatus);
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) 
         ffpky(histptr, TDOUBLE, "PC2_1", &dvalue, card, &tstatus);
 
      tstatus = 0;
      keyname[1] = 'C';
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) {
         dvalue *=  binsize[1];
         ffpky(histptr, TDOUBLE, "CD2_1", &dvalue, card, &tstatus);
      }
       
       /* PC2_2 */
      tstatus = 0;
      ffkeyn("TP", histData.hcolnum[1], card, &tstatus);
      strcat(card,"_");
      ffkeyn(card, histData.hcolnum[1], keyname, &tstatus);
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) 
         ffpky(histptr, TDOUBLE, "PC2_2", &dvalue, card, &tstatus);
        
      tstatus = 0;
      keyname[1] = 'C';
      ffgky(*fptr, TDOUBLE, keyname, &dvalue, card, &tstatus);
      if (!tstatus) {
         dvalue *=  binsize[1];
         ffpky(histptr, TDOUBLE, "CD2_2", &dvalue, card, &tstatus);
      }
    }   
       
    /* finally, close the original file and return ptr to the new image */
    ffclos(*fptr, status);
    *fptr = histptr;

    return(*status);
}