Exemple #1
0
void smf_mapbounds( int fast, Grp *igrp,  int size, const char *system,
                    AstFrameSet *spacerefwcs, int alignsys, int *lbnd_out,
                    int *ubnd_out, AstFrameSet **outframeset, int *moving,
                    smfBox ** boxes, fts2Port fts_port, int *status ) {

  /* Local Variables */
  AstSkyFrame *abskyframe = NULL; /* Output Absolute SkyFrame */
  int actval;           /* Number of parameter values supplied */
  AstMapping *bolo2map = NULL; /* Combined mapping bolo->map
                                  coordinates, WCS->GRID Mapping from
                                  input WCS FrameSet */
  smfBox *box = NULL;          /* smfBox for current file */
  smfData *data = NULL;        /* pointer to  SCUBA2 data struct */
  double dlbnd[ 2 ];    /* Floating point lower bounds for output map */
  drcntrl_bits drcntrl_mask = 0;/* Mask to use for DRCONTROL on this instrument */
  double dubnd[ 2 ];    /* Floating point upper bounds for output map */
  AstMapping *fast_map = NULL; /* Mapping from tracking to absolute map coords */
  smfFile *file = NULL;        /* SCUBA2 data file information */
  int first;                   /* Is this the first good subscan ? */
  AstFitsChan *fitschan = NULL;/* Fits channels to construct WCS header */
  AstFrameSet *fs = NULL;      /* A general purpose FrameSet pointer */
  smfHead *hdr = NULL;         /* Pointer to data header this time slice */
  int i;                       /* Loop counter */
  dim_t j;                     /* Loop counter */
  AstSkyFrame *junksky = NULL; /* Unused SkyFrame argument */
  dim_t k;                     /* Loop counter */
  int lbnd0[ 2 ];              /* Defaults for LBND parameter */
  double map_pa=0;             /* Map PA in output coord system (rads) */
  dim_t maxloop;               /* Number of times to go round the time slice loop */
  dim_t nbadt  = 0;            /* Number of bad time slices */
  dim_t ngoodt = 0;            /* Number of good time slices */
  double par[7];               /* Projection parameters */
  double shift[ 2 ];           /* Shifts from PIXEL to GRID coords */
  AstMapping *oskymap = NULL;  /* Mapping celestial->map coordinates,
                                  Sky <> PIXEL mapping in output
                                  FrameSet */
  AstSkyFrame *oskyframe = NULL;/* Output SkyFrame */
  char *refsys = NULL;         /* Sky system from supplied reference FrameSet */
  dim_t textreme[4];           /* Time index corresponding to minmax TCS posn */
  AstFrame *skyin = NULL;      /* Sky Frame in input FrameSet */
  double skyref[ 2 ];          /* Values for output SkyFrame SkyRef attribute */
  struct timeval tv1;          /* Timer */
  struct timeval tv2;          /* Timer */
  AstMapping *tmap;            /* Temporary Mapping */
  int trim;                    /* Trim borders of bad pixels from o/p image? */
  int ubnd0[ 2 ];              /* Defaults for UBND parameter */
  double x_array_corners[4];   /* X-Indices for corner bolos in array */
  double x_map[4];             /* Projected X-coordinates of corner bolos */
  double y_array_corners[4];   /* Y-Indices for corner pixels in array */
  double y_map[4];             /* Projected X-coordinates of corner bolos */

  /* Main routine */
  if (*status != SAI__OK) return;

  /* Start a timer to see how long this takes */
  smf_timerinit( &tv1, &tv2, status );

  /* Initialize pointer to output FrameSet and moving-source flag */
  *outframeset = NULL;
  *moving = 0;

  /* initialize double precision output bounds and the proj pars */
  for( i = 0; i < 7; i++ ) par[ i ] = AST__BAD;
  dlbnd[ 0 ] = VAL__MAXD;
  dlbnd[ 1 ] = VAL__MAXD;
  dubnd[ 0 ] = VAL__MIND;
  dubnd[ 1 ] = VAL__MIND;

  /* If we have a supplied reference WCS we can use that directly
     without having to calculate it from the data. Replace the requested
     system with the system from the reference FrameSet (take a copy of the
     string since astGetC may re-use its buffer). */
  if (spacerefwcs) {
     oskyframe = astGetFrame( spacerefwcs, AST__CURRENT );
     int nc = 0;
     refsys = astAppendString( NULL, &nc, astGetC( oskyframe, "System" ) );
     system = refsys;
  }

  /* Create array of returned smfBox structures and store a pointer
     to the next one to be initialised. */
  *boxes = astMalloc( sizeof( smfBox ) * size );
  box = *boxes;

  astBegin;

  /* Loop over all files in the Grp */
  first = 1;
  for( i=1; i<=size; i++, box++ ) {

    /* Initialise the spatial bounds of section of the the output cube that is
       contributed to by the current ionput file. */
    box->lbnd[ 0 ] = VAL__MAXD;
    box->lbnd[ 1 ] = VAL__MAXD;
    box->ubnd[ 0 ] = VAL__MIND;
    box->ubnd[ 1 ] = VAL__MIND;

    /* Read data from the ith input file in the group */
    smf_open_file( NULL, igrp, i, "READ", SMF__NOCREATE_DATA, &data, status );

    if (*status != SAI__OK) {
      msgSeti( "I", i );
      errRep( "smf_mapbounds", "Could not open data file no ^I.", status );
      break;
    } else {
      if( *status == SAI__OK ) {
        if( data->file == NULL ) {
          *status = SAI__ERROR;
          errRep( FUNC_NAME, "No smfFile associated with smfData.",
                  status );
          break;

        } else if( data->hdr == NULL ) {
          *status = SAI__ERROR;
          errRep( FUNC_NAME, "No smfHead associated with smfData.",
                  status );
          break;

        } else if( data->hdr->fitshdr == NULL ) {
          *status = SAI__ERROR;
          errRep( FUNC_NAME, "No FITS header associated with smfHead.",
                  status );
          break;

        }
      }
    }

    /* convenience pointers */
    file = data->file;
    hdr = data->hdr;

    /* report name of the input file */
    smf_smfFile_msg( file, "FILE", 1, "<unknown>" );
    msgSeti("I", i);
    msgSeti("N", size);
    msgOutif(MSG__VERB, " ",
             "SMF_MAPBOUNDS: Processing ^I/^N ^FILE",
             status);

/* Check that there are 3 pixel axes. */
    if( data->ndims != 3 ) {
      smf_smfFile_msg( file, "FILE", 1, "<unknown>" );
      msgSeti( "NDIMS", data->ndims );
      *status = SAI__ERROR;
      errRep( FUNC_NAME, "^FILE has ^NDIMS pixel axes, should be 3.",
              status );
      break;
    }

    /* Check that the data dimensions are 3 (for time ordered data) */
    if( *status == SAI__OK ) {

      /* If OK Decide which detectors (GRID coord) to use for
         checking bounds, depending on the instrument in use. */

      switch( hdr->instrument ) {

      case INST__SCUBA2:
        drcntrl_mask = DRCNTRL__POSITION;
        /* 4 corner bolometers of the subarray */
        x_array_corners[0] = 1;
        x_array_corners[1] = 1;
        x_array_corners[2] = (data->dims)[0];
        x_array_corners[3] = (data->dims)[0];

        y_array_corners[0] = 1;
        y_array_corners[1] = (data->dims)[1];
        y_array_corners[2] = 1;
        y_array_corners[3] = (data->dims)[1];
        break;

      case INST__AZTEC:
        /* Rough guess for extreme bolometers around the edge */
        x_array_corners[0] = 22;
        x_array_corners[1] = 65;
        x_array_corners[2] = 73;
        x_array_corners[3] = 98;

        y_array_corners[0] = 1; /* Always 1 for AzTEC */
        y_array_corners[1] = 1;
        y_array_corners[2] = 1;
        y_array_corners[3] = 1;
        break;

      case INST__ACSIS:
        smf_find_acsis_corners( data, x_array_corners, y_array_corners,
                                status);
        break;

      default:
        *status = SAI__ERROR;
        errRep(FUNC_NAME, "Don't know how to calculate mapbounds for data created with this instrument", status);
      }
    }

    if( *status == SAI__OK) {
      size_t goodidx = SMF__BADSZT;

      /* Need to build up a frameset based on good telescope position.
         We can not assume that we the first step will be a good TCS position
         so we look for one. If we can not find anything we skip to the
         next file. */
      maxloop = (data->dims)[2];
      for (j=0; j<maxloop; j++) {
        JCMTState state = (hdr->allState)[j];
        if (state.jos_drcontrol >= 0 && state.jos_drcontrol & drcntrl_mask ) {
          /* bad TCS - so try again */
        } else {
          /* Good tcs */
          goodidx = j;
          break;
        }
      }

      if (goodidx == SMF__BADSZT) {
        smf_smfFile_msg( data->file, "FILE", 1, "<unknown>");
        msgOutif( MSG__QUIET, "", "No good telescope positions found in file ^FILE. Ignoring",
                  status );
        smf_close_file( NULL, &data, status );
        continue;
      }

      /* If we are dealing with the first good file, create the output
         SkyFrame. */
      if( first ) {
        first = 0;

        /* Create output SkyFrame if it has not come from a reference */
        if ( oskyframe == NULL ) {

          /* smf_tslice_ast only needs to get called once to set up framesets */
          if( hdr->wcs == NULL ) {
            smf_tslice_ast( data, goodidx, 1, fts_port, status);
          }

          /* Retrieve input SkyFrame */
          skyin = astGetFrame( hdr->wcs, AST__CURRENT );

          smf_calc_skyframe( skyin, system, hdr, alignsys, &oskyframe, skyref,
                             moving, status );

          /* Get the orientation of the map vertical within the output celestial
             coordinate system. This is derived form the MAP_PA FITS header, which
             gives the orientation of the map vertical within the tracking system. */
          map_pa = smf_calc_mappa( hdr, system, skyin, status );

          /* Provide a sensible default for the pixel size based on wavelength */
          par[4] = smf_calc_telres( hdr->fitshdr, status );
          par[4] *= AST__DD2R/3600.0;
          par[5] = par[4];

          /* Calculate the projection parameters. We do not enable autogrid determination
             for SCUBA-2 so we do not need to obtain all the data before calculating
             projection parameters. */
          smf_get_projpar( oskyframe, skyref, *moving, 0, 0, NULL, 0,
                           map_pa, par, NULL, NULL, status );

          if (skyin) skyin = astAnnul( skyin );

        /* If the output skyframe has been supplied, we still need to
           determine whether the source is moving or not, and set the
           reference position. */
        } else {

          /* smf_tslice_ast only needs to get called once to set up framesets */
          if( hdr->wcs == NULL ) {
            smf_tslice_ast( data, goodidx, 1, fts_port, status);
          }

          /* Retrieve input SkyFrame */
          skyin = astGetFrame( hdr->wcs, AST__CURRENT );
          smf_calc_skyframe( skyin, system, hdr, alignsys, &junksky, skyref,
                             moving, status );

          /* Store the sky reference position. If the target is moving,
             ensure the returned SkyFrame represents offsets from the
             reference position rather than absolute coords. */
          astSetD( oskyframe, "SkyRef(1)", skyref[ 0 ] );
          astSetD( oskyframe, "SkyRef(2)", skyref[ 1 ] );
          if( *moving ) astSet( oskyframe, "SkyRefIs=Origin" );

          /* Ensure the Epoch attribute in the map is set to the date of
             the first data in the map, rather than the date in supplied
             reference WCS. */
          astSetD( oskyframe, "Epoch", astGetD( junksky, "Epoch" ) );
        }

        if ( *outframeset == NULL && oskyframe != NULL && (*status == SAI__OK)){
          /* Now created a spatial Mapping. Use the supplied reference frameset
             if supplied */
          if (spacerefwcs) {
            oskymap = astGetMapping( spacerefwcs, AST__BASE, AST__CURRENT );
          } else {
            /* Now populate a FitsChan with FITS-WCS headers describing
               the required tan plane projection. The longitude and
               latitude axis types are set to either (RA,Dec) or (AZ,EL)
               to get the correct handedness. */
            fitschan = astFitsChan ( NULL, NULL, " " );
            smf_makefitschan( astGetC( oskyframe, "System"), &(par[0]),
                              &(par[2]), &(par[4]), par[6], fitschan, status );
            astClear( fitschan, "Card" );
            fs = astRead( fitschan );

            /* Extract the output PIXEL->SKY Mapping. */
            oskymap = astGetMapping( fs, AST__BASE, AST__CURRENT );

            /* Tidy up */
            fs = astAnnul( fs );
          }

          /* Create the output FrameSet */
          *outframeset = astFrameSet( astFrame(2, "Domain=GRID"), " " );

          /* Now add the SkyFrame to it */
          astAddFrame( *outframeset, AST__BASE, oskymap, oskyframe );

          /* Now add a POLANAL Frame if required (i.e. if the input time
             series are POL-2 Q/U values). */
          smf_addpolanal( *outframeset, hdr, status );

          /* Invert the oskymap mapping */
          astInvert( oskymap );

        } /* End WCS FrameSet construction */
      }

      /* Get a copy of the output SkyFrame and ensure it represents
         absolute coords rather than offset coords. */
      abskyframe = astCopy( oskyframe );
      astClear( abskyframe, "SkyRefIs" );
      astClear( abskyframe, "AlignOffset" );

      maxloop = (data->dims)[2];
      if (fast) {
        /* For scan map we scan through looking for largest telescope moves.
           For dream/stare we just look at the start and end time slices to
           account for sky rotation. */

        if (hdr->obsmode != SMF__OBS_SCAN) {
          textreme[0] = 0;
          textreme[1] = (data->dims)[2] - 1;
          maxloop = 2;

        } else {
          const char *tracksys;
          double *ac1list, *ac2list, *bc1list, *bc2list, *p1, *p2, *p3, *p4;
          double flbnd[4], fubnd[4];
          JCMTState state;

          /* If the output and tracking systems are different, get a
             Mapping between them. */
          tracksys = sc2ast_convert_system( (hdr->allState)[goodidx].tcs_tr_sys,
                                            status );
          if( strcmp( system, tracksys ) ) {
             AstSkyFrame *tempsf = astCopy( abskyframe );
             astSetC( tempsf, "System", tracksys );
             AstFrameSet *tempfs = astConvert( tempsf, abskyframe, "" );
             tmap = astGetMapping( tempfs, AST__BASE, AST__CURRENT );
             fast_map = astSimplify( tmap );
             tmap = astAnnul( tmap );
             tempsf = astAnnul( tempsf );
             tempfs = astAnnul( tempfs );
          } else {
             fast_map = NULL;
          }

          /* Copy all ac1/2 positions into two array, and transform them
             from tracking to absolute output sky coords. */
          ac1list = astMalloc( maxloop*sizeof( *ac1list ) );
          ac2list = astMalloc( maxloop*sizeof( *ac2list ) );
          if( *status == SAI__OK ) {
             p1 = ac1list;
             p2 = ac2list;
             for( j = 0; j < maxloop; j++ ) {
                state = (hdr->allState)[ j ];
                *(p1++) = state.tcs_tr_ac1;
                *(p2++) = state.tcs_tr_ac2;
             }
             if( fast_map ) astTran2( fast_map, maxloop, ac1list, ac2list, 1,
                                      ac1list, ac2list );
          }

          /* If the target is moving, we need to adjust these ac1/2 values
             to represent offsets from the base position. */
          if( *moving ) {

          /* Copy all bc1/2 positions into two arrays. */
             bc1list = astMalloc( maxloop*sizeof( *bc1list ) );
             bc2list = astMalloc( maxloop*sizeof( *bc2list ) );
             if( *status == SAI__OK ) {
                p1 = bc1list;
                p2 = bc2list;

                for( j = 0; j < maxloop; j++ ) {
                   state = (hdr->allState)[ j ];
                   *(p1++) = state.tcs_tr_bc1;
                   *(p2++) = state.tcs_tr_bc2;
                }

                /* Transform them from tracking to absolute output sky coords. */
                if( fast_map ) astTran2( fast_map, maxloop, bc1list, bc2list,
                                         1, bc1list, bc2list );

                /* Replace each ac1/2 position with the offsets from the
                   corresponding base position. */
                p1 = bc1list;
                p2 = bc2list;
                p3 = ac1list;
                p4 = ac2list;
                for( j = 0; j < maxloop; j++ ) {
                  smf_offsets( *(p1++), *(p2++), p3++, p4++, status );
                }
             }

             /* We no longer need the base positions. */
             bc1list = astFree( bc1list );
             bc2list = astFree( bc2list );
          }

          /* Transform the ac1/2 position from output sky coords to
             output pixel coords. */
          astTran2( oskymap, maxloop, ac1list, ac2list, 1, ac1list, ac2list );

          /* Find the bounding box containing these pixel coords and the
             time slices at which the boresight touches each edge of this
             box. */
          flbnd[ 0 ] = VAL__MAXD;
          flbnd[ 1 ] = VAL__MAXD;
          fubnd[ 0 ] = VAL__MIND;
          fubnd[ 1 ] = VAL__MIND;
          for( j = 0; j < 4; j++ ) textreme[ j ] = (dim_t) VAL__BADI;

          if( *status == SAI__OK ) {
             p1 = ac1list;
             p2 = ac2list;
             for( j = 0; j < maxloop; j++,p1++,p2++ ) {
                if( *p1 != VAL__BADD && *p2 != VAL__BADD ){

                   if ( *p1 < flbnd[0] ) { flbnd[0] = *p1; textreme[0] = j; }
                   if ( *p2 < flbnd[1] ) { flbnd[1] = *p2; textreme[1] = j; }
                   if ( *p1 > fubnd[0] ) { fubnd[0] = *p1; textreme[2] = j; }
                   if ( *p2 > fubnd[1] ) { fubnd[1] = *p2; textreme[3] = j; }
                }
             }
          }

          maxloop = 4;
          msgSetd("X1", textreme[0]);
          msgSetd("X2", textreme[1]);
          msgSetd("X3", textreme[2]);
          msgSetd("X4", textreme[3]);
          msgOutif( MSG__DEBUG, " ",
                    "Extrema time slices are ^X1, ^X2, ^X3 and ^X4",
                    status);

          ac1list = astFree( ac1list );
          ac2list = astFree( ac2list );

        }
      }

      /* Get the astrometry for all the relevant time slices in this data file */
      for( j=0; j<maxloop; j++ ) {
        dim_t ts;  /* Actual time slice to use */

        /* if we are doing the fast loop, we need to read the time slice
           index from textreme. Else we just use the index */
        if (fast) {
          /* get the index but make sure it is good */
          ts = textreme[j];
          if (ts == (dim_t)VAL__BADI) continue;
        } else {
          ts = j;
        }
        /* Calculate the bolo to map-pixel transformation for this tslice */
        bolo2map = smf_rebin_totmap( data, ts, abskyframe, oskymap,
                                     *moving, fts_port, status );

        if ( *status == SAI__OK ) {
          /* skip if we did not get a mapping this time round */
          if (!bolo2map) continue;

          /* Check corner pixels in the array for their projected extent
             on the sky to set the pixel bounds */
          astTran2( bolo2map, 4, x_array_corners, y_array_corners, 1,
                    x_map, y_map );

          /* Update min/max for this time slice */
          for( k=0; k<4; k++ ) {

            if( x_map[k] != AST__BAD && y_map[k] != AST__BAD ) {
              if( x_map[k] < dlbnd[0] ) dlbnd[0] = x_map[k];
              if( y_map[k] < dlbnd[1] ) dlbnd[1] = y_map[k];
              if( x_map[k] > dubnd[0] ) dubnd[0] = x_map[k];
              if( y_map[k] > dubnd[1] ) dubnd[1] = y_map[k];

              if( x_map[k] < box->lbnd[0] ) box->lbnd[0] = x_map[k];
              if( y_map[k] < box->lbnd[1] ) box->lbnd[1] = y_map[k];
              if( x_map[k] > box->ubnd[0] ) box->ubnd[0] = x_map[k];
              if( y_map[k] > box->ubnd[1] ) box->ubnd[1] = y_map[k];

            } else if( *status == SAI__OK ) {
              *status = SAI__ERROR;
              errRep( FUNC_NAME, "Extreme positions are bad.", status );
              break;
            }
          }
        }
        /* Explicitly annul these mappings each time slice for reduced
           memory usage */
        if (bolo2map) bolo2map = astAnnul( bolo2map );
        if (fs) fs = astAnnul( fs );

        /* Break out of loop over time slices if bad status */
        if (*status != SAI__OK) goto CLEANUP;
      }

      /* Annul any remaining Ast objects before moving on to the next file */
      if (fs) fs = astAnnul( fs );
      if (bolo2map) bolo2map = astAnnul( bolo2map );
    }

    /* Close the data file */
    smf_close_file( NULL, &data, status);

    /* Break out of loop over data files if bad status */
    if (*status != SAI__OK) goto CLEANUP;
  }

  /* make sure we got values - should not be possible with good status */
  if (dlbnd[0] == VAL__MAXD || dlbnd[1] == VAL__MAXD) {
    if (*status == SAI__OK) {
      *status = SAI__ERROR;
      errRep( " ", "Unable to find any valid map bounds", status );
    }
  }

  if (nbadt > 0) {
    msgOutf( "", "   Processed %zu time slices to calculate bounds,"
             " of which %zu had bad telescope data and were skipped",
             status, (size_t)(ngoodt+nbadt), (size_t)nbadt );
  }

  /* If spatial reference wcs was supplied, store par values that result in
     no change to the pixel origin. */
  if( spacerefwcs ){
    par[ 0 ] = 0.5;
    par[ 1 ] = 0.5;
  }

  /* Need to re-align with the interim GRID coordinates */
  lbnd_out[0] = ceil( dlbnd[0] - par[0] + 0.5 );
  ubnd_out[0] = ceil( dubnd[0] - par[0] + 0.5 );
  lbnd_out[1] = ceil( dlbnd[1] - par[1] + 0.5 );
  ubnd_out[1] = ceil( dubnd[1] - par[1] + 0.5 );

  /* Do the same with the individual input file bounding boxes */
  box = *boxes;
  for (i = 1; i <= size; i++, box++) {
    box->lbnd[0] = ceil( box->lbnd[0] - par[0] + 0.5);
    box->ubnd[0] = ceil( box->ubnd[0] - par[0] + 0.5);
    box->lbnd[1] = ceil( box->lbnd[1] - par[1] + 0.5);
    box->ubnd[1] = ceil( box->ubnd[1] - par[1] + 0.5);
  }

  /* Apply a ShiftMap to the output FrameSet to re-align the GRID
     coordinates */
  shift[0] = 2.0 - par[0] - lbnd_out[0];
  shift[1] = 2.0 - par[1] - lbnd_out[1];
  astRemapFrame( *outframeset, AST__BASE, astShiftMap( 2, shift, " " ) );

  /* Set the dynamic defaults for lbnd/ubnd */
  lbnd0[ 0 ] = lbnd_out[ 0 ];
  lbnd0[ 1 ] = lbnd_out[ 1 ];
  parDef1i( "LBND", 2, lbnd0, status );

  ubnd0[ 0 ] = ubnd_out[ 0 ];
  ubnd0[ 1 ] = ubnd_out[ 1 ];
  parDef1i( "UBND", 2, ubnd0, status );

  parGet1i( "LBND", 2, lbnd_out, &actval, status );
  if( actval == 1 ) lbnd_out[ 1 ] = lbnd_out[ 0 ];

  parGet1i( "UBND", 2, ubnd_out, &actval, status );
  if( actval == 1 ) ubnd_out[ 1 ] = ubnd_out[ 0 ];

  /* Ensure the bounds are the right way round. */
  if( lbnd_out[ 0 ] > ubnd_out[ 0 ] ) {
    int itmp = lbnd_out[ 0 ];
    lbnd_out[ 0 ] = ubnd_out[ 0 ];
    ubnd_out[ 0 ] = itmp;
  }

  if( lbnd_out[ 1 ] > ubnd_out[ 1 ] ) {
    int itmp = lbnd_out[ 1 ];
    lbnd_out[ 1 ] = ubnd_out[ 1 ];
    ubnd_out[ 1 ] = itmp;
  }

  /* If borders of bad pixels are being trimmed from the output image,
     then do not allow the user-specified bounds to extend outside the
     default bounding box (since we know that the default bounding box
     encloses all available data). */
  parGet0l( "TRIM", &trim, status );
  if( trim ) {
     if( lbnd_out[ 0 ] < lbnd0[ 0 ] ) lbnd_out[ 0 ] = lbnd0[ 0 ];
     if( lbnd_out[ 1 ] < lbnd0[ 1 ] ) lbnd_out[ 1 ] = lbnd0[ 1 ];
     if( ubnd_out[ 0 ] > ubnd0[ 0 ] ) ubnd_out[ 0 ] = ubnd0[ 0 ];
     if( ubnd_out[ 1 ] > ubnd0[ 1 ] ) ubnd_out[ 1 ] = ubnd0[ 1 ];
  }

  /* Modify the returned FrameSet to take account of the new pixel origin. */
  shift[ 0 ] = lbnd0[ 0 ] - lbnd_out[ 0 ];
  shift[ 1 ] = lbnd0[ 1 ] - lbnd_out[ 1 ];
  if( shift[ 0 ] != 0.0 || shift[ 1 ] != 0.0 ) {
    astRemapFrame( *outframeset, AST__BASE, astShiftMap( 2, shift, " " ) );
  }

/* Report the pixel bounds of the cube. */
  if( *status == SAI__OK ) {
    msgOutif( MSG__NORM, " ", " ", status );
    msgSeti( "XL", lbnd_out[ 0 ] );
    msgSeti( "YL", lbnd_out[ 1 ] );
    msgSeti( "XU", ubnd_out[ 0 ] );
    msgSeti( "YU", ubnd_out[ 1 ] );
    msgOutif( MSG__NORM, " ", "   Output map pixel bounds: ( ^XL:^XU, ^YL:^YU )",
              status );

    if( ( ubnd_out[ 0 ] - lbnd_out[ 0 ] + 1 ) > MAX_DIM ||
        ( ubnd_out[ 1 ] - lbnd_out[ 1 ] + 1 ) > MAX_DIM ) {
      *status = SAI__ERROR;
      errRep( "", FUNC_NAME ": The map is too big. Check your list of input "
              "data files does not include widely separated observations.",
              status );
    }
  }

  /* If no error has occurred, export the returned FrameSet pointer from the
     current AST context so that it will not be annulled when the AST
     context is ended. Otherwise, ensure a null pointer is returned. */
  if( *status == SAI__OK ) {
    astExport( *outframeset );
  } else {
    *outframeset = astAnnul( *outframeset );
  }

  msgOutiff( SMF__TIMER_MSG, "",
             "Took %.3f s to calculate map bounds",
             status, smf_timerupdate( &tv1, &tv2, status ) );

  /* Clean Up */
 CLEANUP:
  if (*status != SAI__OK) {
    errRep(FUNC_NAME, "Unable to determine map bounds", status);
  }
  if (oskymap) oskymap  = astAnnul( oskymap );
  if (bolo2map) bolo2map = astAnnul( bolo2map );
  if (fitschan) fitschan = astAnnul( fitschan );

  if( data != NULL )
    smf_close_file( NULL, &data, status );

  refsys = astFree( refsys );

  astEnd;

}
void smf_mapbounds_approx( Grp *igrp,  size_t index, char *system,
			   int *lbnd_out, int *ubnd_out, AstFrameSet **outframeset,
			   int *moving, int *status ) {

  /* Local variables */
  smfData *data = NULL;        /* pointer to  SCUBA2 data struct */
  int dxpix;                   /* Map X offset in pixels */
  int dypix;                   /* Map Y offset in pixels */
  smfFile *file = NULL;        /* SCUBA2 data file information */
  AstFitsChan *fitschan = NULL;/* Fits channels to construct WCS header */
  AstFrameSet *fs = NULL;      /* A general purpose FrameSet pointer */
  smfHead *hdr = NULL;         /* Pointer to data header this time slice */
  double hghtbox;              /* Map height in arcsec */
  int hghtpix;                 /* RA-Dec map height in pixels */
  int i;                       /* loop counter */
  dim_t k;                     /* Loop counter */
  double maphght = 0.0;        /* Map height in radians */
  double mappa = 0.0;          /* Map position angle in radians */
  double mapwdth = 0.0;        /* Map width in radians */
  double mapx;                 /* Map X offset in radians */
  double mapy;                 /* Map Y offset in radians */
  double par[7];               /* Projection parameters */
  double pixsize = 0.0;        /* Requested pixel size */
  double shift[ 2 ];           /* Shifts from PIXEL to GRID coords */
  AstMapping *sky2map = NULL;  /* Mapping celestial->map coordinates */
  AstSkyFrame *skyframe = NULL;/* Output SkyFrame */
  AstFrame *skyin = NULL;      /* Sky Frame in input FrameSet */
  double skyref[ 2 ];          /* Values for output SkyFrame SkyRef attribute */
  AstFrameSet *swcsin = NULL;  /* FrameSet describing input WCS */
  int temp;                    /* Temporary variable  */
  double wdthbox;              /* Map width in arcsec */
  int wdthpix;                 /* RA-Dec map width in pixels */
  double x_array_corners[4];   /* X-Indices for corner bolos in array */
  double y_array_corners[4];   /* Y-Indices for corner pixels in array */

  /* Main routine */
  if (*status != SAI__OK) return;

  /* Begin an AST context to ensure that all AST objects are annuled
     before returning to caller */
  astBegin;

  /* Initialize output frameset pointer to NULL */
  *outframeset = NULL;
  for( i = 0; i < 7; i++ ) par[ i ] = AST__BAD;

  /* Read data from the given input file in the group - note index
     should be 1 as we use the first file in the Grp to define the map
     bounds */
  smf_open_file( igrp, index, "READ", SMF__NOCREATE_DATA, &data, status );

  /* Simply abort if it is not a scan */
  if (*status == SAI__OK && data->hdr->obsmode != SMF__OBS_SCAN) {
    *status = SAI__ERROR;
    errRep(" ", "Can not call smf_mapbounds_approx with non-scan observation"
           " (possible programming error)", status);
    goto CLEANUP;
  }

  /* Retrieve file name for use feedback */
  file = data->file;
  smf_smfFile_msg( file, "FILE", 1, "<unknown>" );
  if( *status == SAI__OK ) {
    msgOutif(MSG__VERB, " ",
	     "SMF_MAPBOUNDS_APPROX: Processing ^FILE",
	     status);
  } else {
    errRep( "smf_mapbounds_approx", "Couldn't open input file, ^FILE", status );
  }

  /* Check that the data dimensions are 3 (for time ordered data) */
  if( *status == SAI__OK ) {
    if( data->ndims != 3 ) {
      smf_smfFile_msg( file, "FILE", 1, "<unknown>" );
      msgSeti("THEDIMS", data->ndims);
      *status = SAI__ERROR;
      errRep("smf_mapbounds_approx",
	     "^FILE data has ^THEDIMS dimensions, should be 3.",
	     status);
    }
  }

  /* Construct the WCS for the first time slice in this file */
  smf_tslice_ast( data, 1, 1, NO_FTS, status);

  /* Retrieve header for later constructing output WCS */
  if( *status == SAI__OK) {
    hdr = data->hdr;
    swcsin = hdr->wcs;

    /* Calculate default pixel size */
    pixsize = smf_calc_telres( hdr->fitshdr, status );

    /* Get the user defined pixel size - we trust that smf_get_projpar will
       also read PIXSIZE and get the same answer. We pre-fill par[] to allow
       PIXSIZE=! to accept the dynamic default in both places.*/
    parGdr0d( "PIXSIZE", pixsize, 0, 60, 1, &pixsize, status );
    par[4] = pixsize*AST__DD2R/3600.0;
    par[5] = par[4];

    /* Retrieve input SkyFrame */
    skyin = astGetFrame( swcsin, AST__CURRENT );

    /* Retrieve map height and width from header - will be undef for
       non-scan so set up defaults first. */
    mapwdth = 0.0;
    maphght = 0.0;
    smf_getfitsd( hdr, "MAP_WDTH", &mapwdth, status );
    smf_getfitsd( hdr, "MAP_HGHT", &maphght, status );

    /* Make an approximation if map height and width are not set -
       note that this should ONLY apply for non-scan mode data */
    if ( !mapwdth || !maphght ) {
      if (*status == SAI__OK) {
        *status = SAI__ERROR;
        errRep(" ", "MAP_WDTH and MAP_HGHT must be > 0", status);
        goto CLEANUP;
      }
    }

    mapx = 0.0;   /* Used if the FITS keyword values are undefed */
    mapy = 0.0;
    smf_getfitsd( hdr, "MAP_X", &mapx, status );
    smf_getfitsd( hdr, "MAP_Y", &mapy, status );

    /* Convert map Position Angle to radians */
    mappa = 0.0;
    smf_fits_getD( hdr, "MAP_PA", &mappa, status );
    mappa *= AST__DD2R;

    /* Calculate size of output map in pixels */
    /* Note: this works for the simulator... */
    wdthbox = mapwdth*fabs(cos(mappa)) + maphght*fabs(sin(mappa));
    hghtbox = maphght*fabs(cos(mappa)) + mapwdth*fabs(sin(mappa));
    wdthpix = (int) ( wdthbox / pixsize);
    hghtpix = (int) ( wdthbox / pixsize);
    dxpix = (int) (mapx / pixsize);
    dypix = (int) (mapy / pixsize);

    /* Get the offsets for each corner of the array */
    temp = (wdthpix - 1) / 2;
    x_array_corners[0] = dxpix - temp;
    x_array_corners[1] = dxpix - temp;
    x_array_corners[2] = dxpix + temp;
    x_array_corners[3] = dxpix + temp;

    temp = (hghtpix - 1) / 2;
    y_array_corners[0] = dypix - temp;
    y_array_corners[1] = dypix + temp;
    y_array_corners[2] = dypix - temp;
    y_array_corners[3] = dypix + temp;

    lbnd_out[0] = x_array_corners[0];
    ubnd_out[0] = x_array_corners[0];
    lbnd_out[1] = y_array_corners[0];
    ubnd_out[1] = y_array_corners[0];

    /* Update min/max  */
    for( k=0; k<4; k++ ) {
      if( x_array_corners[k] < lbnd_out[0] ) lbnd_out[0] = x_array_corners[k];
      if( y_array_corners[k] < lbnd_out[1] ) lbnd_out[1] = y_array_corners[k];
      if( x_array_corners[k] > ubnd_out[0] ) ubnd_out[0] = x_array_corners[k];
      if( y_array_corners[k] > ubnd_out[1] ) ubnd_out[1] = y_array_corners[k];
    }

  } else {
    goto CLEANUP;
  }

  /* Now create the output FrameSet. */
  smf_calc_skyframe( skyin, system, hdr, 0, &skyframe, skyref, moving,
                     status );

  /* Get the orientation of the map vertical within the output celestial
     coordinate system. This is derived form the MAP_PA FITS header, which
     gives the orientation of the map vertical within the tracking system. */
  mappa = smf_calc_mappa( hdr, system, skyin, status );

  /* Calculate the projection parameters. We do not enable autogrid determination
     for SCUBA-2 so we do not need to obtain all the data before calculating
     projection parameters. */
  smf_get_projpar( skyframe, skyref, *moving, 0, 0, NULL, 0,
                   mappa, par, NULL, NULL, status );



  /* Now populate a FitsChan with FITS-WCS headers describing the
     required tan plane projection. The longitude and latitude axis
     types are set to either (RA,Dec) or (AZ,EL) to get the correct
     handedness. */
  fitschan = astFitsChan ( NULL, NULL, " " );
  smf_makefitschan( astGetC( skyframe, "System"), &(par[0]),
                    &(par[2]), &(par[4]), par[6], fitschan, status );
  astClear( fitschan, "Card" );
  fs = astRead( fitschan );

  /* Extract the output PIXEL->SKY Mapping - note this is will be
     inverted later to create the sk2map mapping */
  sky2map = astGetMapping( fs, AST__BASE, AST__CURRENT );

  /* Create the output FrameSet */
  *outframeset = astFrameSet( astFrame(2, "Domain=GRID"), " " );

  /* Now add the SkyFrame to it */
  astAddFrame( *outframeset, AST__BASE, sky2map, skyframe );

  /* Apply a ShiftMap to the output FrameSet to re-align the GRID
     coordinates */
  shift[0] = -lbnd_out[0];
  shift[1] = -lbnd_out[1];
  astRemapFrame( *outframeset, AST__BASE, astShiftMap( 2, shift, " " ) );

  astExport( *outframeset );

/* Report the pixel bounds of the cube. */
   if( *status == SAI__OK ) {
      msgOutif( MSG__NORM, " ", " ", status );
      msgSeti( "XL", lbnd_out[ 0 ] );
      msgSeti( "YL", lbnd_out[ 1 ] );
      msgSeti( "XU", ubnd_out[ 0 ] );
      msgSeti( "YU", ubnd_out[ 1 ] );
      msgOutif( MSG__NORM, " ", "   Output map pixel bounds: ( ^XL:^XU, ^YL:^YU )",
                status );
   }


  /* Change the pixel bounds to be consistent with the new CRPIX */
  ubnd_out[0] -= lbnd_out[0]-1;
  lbnd_out[0] = 1;

  ubnd_out[1] -= lbnd_out[1]-1;
  lbnd_out[1] = 1;

  /* Clean Up */
 CLEANUP:
  if (*status != SAI__OK) {
    errRep(FUNC_NAME, "Unable to determine map bounds", status);
  }

  if( data != NULL )
    smf_close_file( &data, status);

  astEnd;

}