external/io_grib1/MEL_grib1/gribgetgds.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include "dprints.h"            /* for dprints & func prototypes  */
   4 #include "gribfuncs.h"          /* prototypes */
   5 /*
   6   REVISION/MODIFICATION HISTORY:
   7        03/07/94 written by Mugur Georgescu CSC, Monterey CA
   8        02/01/96 modified by Steve Lowe SAIC, Monterey CA
   9        06/19/96 modified by Alice Nakajima SAIC, Monterey CA
  10        10/15/97/ATN init usData_type in Projection struct too
  11        02/18/98/atn replace projection ids with constants
  12 *
  13 *******************************************************************
  14 * A.  FUNCTION  gribgetgds
  15 *       Decode the Grid Description Section (GDS) from the provided
  16 *       pointer location and store its the in the internal GDS structure;
  17 *
  18 *    INTERFACE:
  19 *       int gribgetgds (curr_ptr, gds, errmsg)
  20 *
  21 *    ARGUMENTS (I=input, O=output, I&O=input and output):
  22 *      (I)  char *curr_ptr;        points to 1st octet of GDS
  23 *      (O)  grid_desc_sec *gds;    internal GDS structure to be filled
  24 *      (O)  char *errmsg;          returned filled if error occurred
  25 *
  26 *    RETURN CODE:
  27 *       0>  success, struct grid_desc_sec filled;
  28 *       1>  unsupported projection number, errmsg filled;
  29 *       2>  section length too short, errmsg filled;
  30 *******************************************************************
  31 */
  32
  33 #if PROTOTYPE_NEEDED
  34 int gribgetgds ( char *curr_ptr, grid_desc_sec *gds, char *errmsg)
  35 #else
  36 int gribgetgds ( curr_ptr, gds, errmsg)
  37                 char *curr_ptr;
  38                 grid_desc_sec *gds;
  39                 char *errmsg;
  40 #endif
  41 {
  42 char *func= "gribgetgds";
  43 char *in = curr_ptr;      /* pointer to the message */
  44 unsigned long skip;             /* bits to be skipped */
  45 unsigned long something;  /* value extracted from message */
  46 int sign;                 /* sign + or - */
  47 int status;
  48 FILE *fp;
  49 int i;
  50
  51  DPRINT1 ("Entering %s\n", func);
  52 /*
  53 *
  54 * A.0      INIT status to good, skip to 0
  55 */
  56  status=0;  skip=0;
  57 /*
  58 *
  59 * A.1      FUNCTION gbyte  !GDS length
  60 *          IF (length < 32 bytes) THEN
  61 *             SET error status of 2   !length too short
  62 *             CONTINUE to load as much info as possible into
  63 *             structure 'grid_desc_sec' but will return with error
  64 *          ENDIF
  65 */
  66  gbyte(in,&something,&skip,24); DPRINT0 ("gds->head.uslength\n");
  67  gds->head.uslength = (unsigned short) something;
  68  if (gds->head.uslength < 32) {
  69     sprintf(errmsg,
  70     "GDS length too short (%ld).  Will attempt to load struct grid_desc_sec\n",
  71     gds->head.uslength);
  72     status = 2;         /* corrupt length */
  73    }
  74
  75 /*
  76 *
  77 * A.2      FUNCTION gbyte  !parm_nv
  78 */
  79  gbyte(in,&something,&skip,8); DPRINT0 ("gds->head.usNum_v\n");
  80  gds->head.usNum_v =(short) something;
  81 /*
  82 *
  83 * A.3      FUNCTION gbyte  !parm_pv_pl
  84 */
  85  gbyte(in,&something,&skip,8); DPRINT0 ("gds->head.usPl_Pv\n");
  86  gds->head.usPl_Pv = (short) something;
  87
  88 /*
  89 *
  90 * A.4      FUNCTION gbyte  !data representation type
  91 */
  92  gbyte(in,&something,&skip,8); DPRINT0 ("gds->head.usData_type\n");
  93  gds->head.usData_type = (short) something;
  94
  95 /* Remainder of GDS is projection dependent */
  96 /*
  97 *
  98 * A.5      SWITCH (data type)
  99 */
 100
 101  switch(gds->head.usData_type)
 102   {
 103    case LATLON_PRJ:     /* Lat/Lon Grid */
 104    case GAUSS_PRJ:      /* Gaussian Latitude/Longitude grid */
 105    case ROT_LATLON_PRJ:         /* Rotated Lat/Lon */
 106    case ROT_GAUSS_PRJ:          /* Rotated Gaussian */
 107    case STR_LATLON_PRJ:         /* Stretched Lat/Lon */
 108    case STR_GAUSS_PRJ :         /* Stretched Gaussian */
 109    case STR_ROT_LATLON_PRJ :  /* Stretched and Rotated Lat/Lon */
 110    case STR_ROT_GAUSS_PRJ :   /* Stretched and Rotated Gaussian */
 111 /*
 112 *           case latlon:
 113 *           case gaussian_latlon:
 114 *           case rotated gaussian:
 115 *           case stretched latlon:
 116 *           case stretched gaussian:
 117 *           case stretched & rotated latlon:
 118 *           case stretched & rotated gaussian:
 119 *                 Mark the Projection type
 120 *                 FUNCTION gbyte !get Number of Columns
 121 */
 122        gds->llg.usData_type = gds->head.usData_type;
 123
 124        gbyte(in, &something, &skip, 16);
 125        DPRINT0 ("gds->llg.usNi\n");
 126        gds->llg.usNi = (int) something;                   /* get Ni */
 127
 128 /*
 129 *                 FUNCTION gbyte !get Number of Rows
 130 */
 131        gbyte(in, &something, &skip, 16);
 132        DPRINT0 ("gds->llg.usNj\n");
 133        gds->llg.usNj = (int) something;                   /* get Nj */
 134
 135 /*
 136 *                 FUNCTION gbyte !get Latitude of First point
 137 */
 138        gbyte(in,&something,&skip,24);
 139        DPRINT0 ("Sign & gds->llg.lLat1 \n");
 140        sign = (int)(something >> 23) & 1;                 /* get sign */
 141        gds->llg.lLat1 = (long) (something) & 8388607;     /* get La1 */
 142        if(sign)                                           /* negative value */
 143           gds->llg.lLat1 = - gds->llg.lLat1;              /* multiply by -1 */
 144
 145 /*
 146 *                 FUNCTION gbyte !get Longitude of First point
 147 */
 148        gbyte(in,&something,&skip,24);
 149        DPRINT0 ("Sign & gds->llg.lLon1 \n");
 150        sign = (int)(something >> 23) & 1;                 /* get sign */
 151        gds->llg.lLon1 = (long) (something) & 8388607;     /* get Lo1 */
 152        if(sign)                                           /* negative value */
 153            gds->llg.lLon1 = - gds->llg.lLon1;             /* multiply by -1 */
 154
 155 /*
 156 *                 FUNCTION gbyte !get resolution & comp flags
 157 */
 158        gbyte(in,&something,&skip,8);
 159        DPRINT0 ("gds->llg.usRes_flag\n");
 160        gds->llg.usRes_flag = (short) something;           /* get resolution & comp flags */
 161
 162        gbyte(in,&something,&skip,24);
 163        DPRINT0 ("Sign & gds->llg.lLat2 \n");
 164 /*
 165 *                 FUNCTION gbyte !get Latitude of Last point
 166 */
 167        sign = (int)(something >> 23) & 1;                 /* get sign */
 168        gds->llg.lLat2 = (long) (something) & 8388607;     /* get La2 */
 169        if(sign)                                           /* negative value */
 170           gds->llg.lLat2 = - gds->llg.lLat2;              /* multiply by -1 */
 171
 172 /*
 173 *                 FUNCTION gbyte !get Longitude of Last point
 174 */
 175        gbyte(in,&something,&skip,24);
 176        DPRINT0 ("Sign & gds->llg.lLon2 \n");
 177        sign = (int)(something >> 23) & 1;                 /* get sign */
 178        gds->llg.lLon2 = (long) (something) & 8388607;     /* get Lo2 */
 179        if(sign)                                           /* negative value */
 180           gds->llg.lLon2 = - gds->llg.lLon2;              /* multiply by -1 */
 181
 182 /*
 183 *                 FUNCTION gbyte !get Longitudinal Increment
 184 */
 185        gbyte(in,&something,&skip,16);
 186        DPRINT0 ("gds->llg.iDi\n");
 187        gds->llg.iDi = (int) something;                    /* get Di */
 188
 189 /*
 190 *                 FUNCTION gbyte !get Latitudinal Increment
 191 */
 192        gbyte(in,&something,&skip,16);
 193        DPRINT0 ("gds->llg.iDj\n");
 194        gds->llg.iDj = (int) something;                    /* get Dj */
 195
 196 /*
 197 *                 FUNCTION gbyte !get scanning mode
 198 */
 199        gbyte(in,&something,&skip,8);
 200        DPRINT0 ("gds->llg.usScan_mode\n");
 201        gds->llg.usScan_mode = (short) something;    /* get scaning mode flag */
 202
 203 /*
 204 *                 FUNCTION gbyte !get reserved octets 29-32
 205 */
 206        gbyte(in,&something,&skip,32);
 207        DPRINT0 ("gds->llg.usZero\n");
 208        gds->llg.usZero = (long) something; /* get reserved octets 29 - 32 */
 209
 210        if (gds->head.usNum_v > 0) {
 211 /*
 212 *                 FUNCTION gbyte !get south pole lat
 213 */
 214          gbyte(in,&something,&skip,24);
 215          DPRINT0 ("Sign & gds->llg.lLat_southpole \n");
 216          sign = (int)(something >> 23) & 1;                      /* get sign */
 217          gds->llg.lLat_southpole = (long)(something) & 8388607; /* southpole lat*/
 218          if(sign)                                            /* negative value */
 219            gds->llg.lLat_southpole = - gds->llg.lLat_southpole; /* multiply -1 */
 220
 221 /*
 222 *                 FUNCTION gbyte !get south pole lon
 223 */
 224          gbyte(in,&something,&skip,24);
 225          DPRINT0 ("Sign & gds->llg.lLon_southpole \n");
 226          sign = (int)(something >> 23) & 1;                      /* get sign */
 227          gds->llg.lLon_southpole =(long)(something) & 8388607; /* southpole lon*/
 228          if(sign)                 /* negative value , multiply by -1 */
 229            gds->llg.lLon_southpole = - gds->llg.lLon_southpole;
 230
 231 /*
 232 *                 FUNCTION gbyte !angle of rotation
 233 */
 234          gbyte(in,&something,&skip,24);
 235          DPRINT0 ("gds->llg.lRotate\n");
 236          gds->llg.lRotate = (long) something;          /* get angle of rotation */
 237
 238 /*
 239 *                 FUNCTION gbyte !get lat pole stretching
 240 */
 241          gbyte(in,&something,&skip,24);
 242          DPRINT0 ("Sign & gds->llg.lPole_lat \n");
 243          sign = (int)(something >> 23) & 1;                 /* get sign */
 244          gds->llg.lPole_lat = (long)something & 8388607; /* lat pole stretching */
 245          if(sign)                                           /* negative value */
 246            gds->llg.lPole_lat = - gds->llg.lPole_lat;      /* multiply by -1 */
 247
 248 /*
 249 *                 FUNCTION gbyte !get lon pole stretching
 250 */
 251          gbyte(in,&something,&skip,24);
 252          DPRINT0 ("Sign & gds->llg.lPole_lon \n");
 253          sign = (int)(something >> 23) & 1;                 /* get sign */
 254          gds->llg.lPole_lon= (long)(something) & 8388607; /* lon pole stretching*/
 255          if(sign)                                           /* negative value */
 256            gds->llg.lPole_lon = - gds->llg.lPole_lon;      /* multiply by -1 */
 257
 258          gbyte(in,&something,&skip,24);
 259          DPRINT0 ("gds->llg.lStretch\n");
 260          gds->llg.lStretch = (long) something;
 261        }
 262
 263 /*
 264  *                FUNCTION gbyte !get number of columns in each row
 265  */
 266        if (gds->llg.usNi == 65535) {
 267          if (gds->head.thin == NULL) {
 268            gds->head.thin = (int *)malloc(gds->llg.usNj*sizeof(int));
 269          } else {
 270            gds->head.thin = (int *)realloc(gds->head.thin,
 271                                            gds->llg.usNj*sizeof(int));
 272          }
 273          if (gds->head.thin == NULL) {
 274            sprintf(errmsg,
 275                    "%s: failed to create array[%d] for thinned grid information",
 276                    func, gds->head.thin);
 277            goto BYE;
 278          }
 279          for (i = 0; i<gds->llg.usNj; i++) {
 280            gbyte(in,&something,&skip,16);
 281            gds->head.thin[i] = (short)something;
 282          }
 283        } else {
 284          gds->head.thin = NULL;
 285        }
 286        break;
 287
 288     case MERC_PRJ:    /* Mercator Projection Grid               */
 289 /*
 290 *           case Mercator Projection Grid:
 291 *                 Mark the Projection type
 292 *                 FUNCTION gbyte !get Number of Columns
 293 */
 294        gds->merc.usData_type = gds->head.usData_type;
 295
 296        gbyte(in,&something,&skip,16);
 297        DPRINT0 ("gds->merc.cols\n");
 298        gds->merc.cols = (int) something;                  /* get Ni */
 299 /*
 300 *                 FUNCTION gbyte !get Number of Rows
 301 */
 302        gbyte(in,&something,&skip,16);
 303        DPRINT0 ("gds->merc.rows\n");
 304        gds->merc.rows = (int) something;                  /* get Nj */
 305
 306 /*
 307 *                 FUNCTION gbyte !get Latitude of First Point
 308 */
 309        gbyte(in,&something,&skip,24);
 310        DPRINT0 ("Sign & gds->merc.first_lat\n");
 311        sign = (int)(something >> 23) & 1;                   /* get sign */
 312        gds->merc.first_lat = (long) (something) & 8388607;  /* get La1 */
 313        if(sign)                                             /* negative value */
 314           gds->merc.first_lat = - gds->merc.first_lat;      /* multiply by -1 */
 315
 316 /*
 317 *                 FUNCTION gbyte !get Longitude of First Point
 318 */
 319        gbyte(in,&something,&skip,24);
 320        DPRINT0 ("Sign & gds->merc.first_lon\n");
 321        sign = (int)(something >> 23) & 1;                   /* get sign */
 322        gds->merc.first_lon = (long) (something) & 8388607;  /* get Lo1 */
 323        if(sign)                                             /* negative value */
 324           gds->merc.first_lon = - gds->merc.first_lon;      /* multiply by -1 */
 325
 326 /*
 327 *                 FUNCTION gbyte !get resolution & comp flag
 328 */
 329        gbyte(in,&something,&skip,8);
 330        DPRINT0 ("gds->merc.usRes_flag\n");
 331        gds->merc.usRes_flag = (short) something;  /* resolution & comp flags */
 332
 333 /*
 334 *                 FUNCTION gbyte !get Latitude of Last point
 335 */
 336        gbyte(in,&something,&skip,24);
 337        DPRINT0 ("Sign & gds->merc.La2\n");
 338        sign = (int)(something >> 23) & 1;                   /* get sign */
 339        gds->merc.La2 = (long) (something) & 8388607;        /* get La2 */
 340        if(sign)                                             /* negative value */
 341           gds->merc.La2 = - gds->merc.La2;                  /* multiply by -1 */
 342
 343 /*
 344 *                 FUNCTION gbyte !get Longitude of Last point
 345 */
 346        gbyte(in,&something,&skip,24);
 347        DPRINT0 ("Sign & gds->merc.Lo2\n");
 348        sign = (int)(something >> 23) & 1;                   /* get sign */
 349        gds->merc.Lo2 = (long) (something) & 8388607;        /* get Lo2 */
 350        if(sign)                                             /* negative value */
 351           gds->merc.Lo2 = - gds->merc.Lo2;                  /* multiply by -1 */
 352
 353 /*
 354 *                 FUNCTION gbyte !get Latitude where projection intersects Earth
 355 */
 356        gbyte(in,&something,&skip,24);
 357        DPRINT0 ("Sign & gds->merc.latin\n");
 358        sign = (int)(something >> 23) & 1;                   /* get sign */
 359        gds->merc.latin = (long) (something) & 8388607;      /* get latin */
 360        if(sign)                                             /* negative value */
 361           gds->merc.latin = - gds->merc.latin;              /* multiply by -1 */
 362
 363        skip += 8;      /* skip over the reserved octet */
 364
 365 /*
 366 *                 FUNCTION gbyte !get scanning mode flag
 367 */
 368        gbyte(in,&something,&skip,8);
 369        DPRINT0 ("gds->merc.usScan_mode\n");
 370        gds->merc.usScan_mode = (short) something;            /* get scaning mode flag */
 371
 372 /*
 373 *                 FUNCTION gbyte !get Longitudinal Increment
 374 */
 375        gbyte(in,&something,&skip,24);
 376        DPRINT0 ("gds->merc.lon_inc\n");
 377        gds->merc.lon_inc = (float) something;               /* get Di */
 378
 379 /*
 380 *                 FUNCTION gbyte !get Latitudinal Increment
 381 */
 382        gbyte(in,&something,&skip,24);
 383        DPRINT0 ("gds->merc.lat_inc\n");
 384        gds->merc.lat_inc = (float) something;               /* get Dj */
 385
 386        gbyte(in,&something,&skip,32);
 387        DPRINT0 ("gds->merc.usZero\n");
 388        gds->merc.usZero = (long) something;
 389
 390        if (gds->merc.cols == 65535) {
 391          gds->head.thin = (int *)calloc(gds->merc.rows,sizeof(int));
 392          if (gds->head.thin == NULL) {
 393            sprintf(errmsg,
 394                    "%s: failed to create array[%d] for thinned grid information",
 395                    func, gds->head.thin);
 396            goto BYE;
 397          }
 398          for (i = 0; i<gds->merc.rows; i++) {
 399            gbyte(in,&something,&skip,16);
 400            gds->head.thin[i] = (short)something;
 401          }
 402        } else {
 403          gds->head.thin = NULL;
 404        }
 405
 406        break;
 407
 408     case POLAR_PRJ:    /* Polar Stereographic Projection Grid    */
 409 /*
 410 *           case Polar Stereographic Projection Grid:
 411 *                 Mark the Projection type
 412 *                 FUNCTION gbyte !get Number of Columns
 413 */
 414        gds->pol.usData_type = gds->head.usData_type;
 415
 416        gbyte(in,&something,&skip,16);
 417        DPRINT0 ("gds->pol.usNx\n");
 418        gds->pol.usNx = (short) something;                   /* get Nx */
 419
 420 /*
 421 *                 FUNCTION gbyte !get Number of Rows
 422 */
 423        gbyte(in,&something,&skip,16);
 424        DPRINT0 ("gds->pol.usNy\n");
 425        gds->pol.usNy = (short) something;                   /* get Ny */
 426
 427 /*
 428 *                 FUNCTION gbyte !get Latitude of First point
 429 */
 430        gbyte(in,&something,&skip,24);
 431        DPRINT0 ("Sign & gds->pol.lLat1\n");
 432        sign = (int)(something >> 23) & 1;                   /* get sign */
 433        gds->pol.lLat1 = (long)  (something) & 8388607;      /* get La1 */
 434        if(sign)                                             /* negative value */
 435           gds->pol.lLat1 = - gds->pol.lLat1;                /* multiply by -1 */
 436
 437 /*
 438 *                 FUNCTION gbyte !get Longitude of First point
 439 */
 440        gbyte(in,&something,&skip,24);
 441        DPRINT0 ("Sign & gds->pol.lLon1\n");
 442        sign = (int)(something >> 23) & 1;                   /* get sign */
 443        gds->pol.lLon1 = (long) (something) & 8388607;       /* get Lo1 */
 444        if(sign)                                             /* negative value */
 445           gds->pol.lLon1 = - gds->pol.lLon1;                /* multiply by -1 */
 446
 447 /*
 448 *                 FUNCTION gbyte !get resolution & comp flag
 449 */
 450        gbyte(in,&something,&skip,8);
 451        DPRINT0 ("gds->pol.usRes_flag\n");
 452        gds->pol.usRes_flag = (short) something;             /* get resolution & comp flags */
 453
 454 /*
 455 *                 FUNCTION gbyte !get Orientation Longitude
 456 */
 457        gbyte(in,&something,&skip,24);
 458        DPRINT0 ("Sign & gds->pol.lLon_orient\n");
 459        sign = (int)(something >> 23) & 1;                    /* get sign */
 460        gds->pol.lLon_orient = (long) (something) & 8388607;  /* Orientation */
 461        if(sign)      /* negative value , multiply by -1 */
 462           gds->pol.lLon_orient = - gds->pol.lLon_orient;
 463
 464 /*
 465 *                 FUNCTION gbyte !get Increment along a Row
 466 */
 467        gbyte(in,&something,&skip,24);
 468        DPRINT0 ("gds->pol.ulDx\n");
 469        gds->pol.ulDx = (float) something;                   /* get Dx */
 470
 471 /*
 472 *                 FUNCTION gbyte !get Increment along a Column
 473 */
 474        gbyte(in,&something,&skip,24);
 475        DPRINT0 ("gds->pol.ulDy\n");
 476        gds->pol.ulDy = (float) something;                   /* get Dy */
 477
 478 /*
 479 *                 FUNCTION gbyte !get projection center flag
 480 */
 481        gbyte(in,&something,&skip,8);
 482        DPRINT0 ("gds->pol.usProj_flag\n");
 483        gds->pol.usProj_flag = (short) something;  /* Projection center flag */
 484
 485 /*
 486 *                 FUNCTION gbyte !get scanning mode
 487 */
 488        gbyte(in,&something,&skip,8);
 489        DPRINT0 ("gds->pol.usScan_mode\n");
 490        gds->pol.usScan_mode = (short) something;     /* get scaning mode flag */
 491
 492 /*
 493 *                 FUNCTION gbyte !reserved zero
 494 */
 495        gbyte(in,&something,&skip,32);
 496        DPRINT0 ("gds->pol.usZero\n");
 497        gds->pol.usZero = (int) something;            /* get Reserved zero */
 498
 499        if (gds->pol.usNx == 65535) {
 500          gds->head.thin = (int *)calloc(gds->pol.usNy,sizeof(int));
 501          if (gds->head.thin == NULL) {
 502            sprintf(errmsg,
 503                    "%s: failed to create array[%d] for thinned grid information",
 504                    func, gds->head.thin);
 505            goto BYE;
 506          }
 507          for (i = 0; i<gds->pol.usNy; i++) {
 508            gbyte(in,&something,&skip,16);
 509            gds->head.thin[i] = (short)something;
 510          }
 511        } else {
 512          gds->head.thin = NULL;
 513        }
 514
 515        break;
 516
 517    case LAMB_PRJ:               /* Lambert Conformal */
 518    case ALBERS_PRJ:             /* Albers equal-area */
 519    case OBLIQ_LAMB_PRJ:         /* Oblique Lambert Conformal */
 520 /*
 521 *           case Lambert conformal, secant or tangent, conical or bipolar:
 522 *           case Albers equal-area, secant or tangent, conical or bipolar:
 523 *           case Oblique Lambert conformal:
 524 *                 Mark the Projection type
 525 *                 FUNCTION gbyte !get Number of Columns
 526 */
 527        gds->lam.usData_type = gds->head.usData_type;
 528
 529        gbyte(in,&something,&skip,16);
 530        DPRINT0 ("gds->lam.iNx\n");
 531        gds->lam.iNx = (int) something;                      /* get Nx */
 532
 533 /*
 534 *                 FUNCTION gbyte !get Number of Rows
 535 */
 536        gbyte(in,&something,&skip,16);
 537        DPRINT0 ("gds->lam.iNy\n");
 538        gds->lam.iNy = (int) something;                      /* get Ny */
 539
 540 /*
 541 *                 FUNCTION gbyte !get Latitude of First Point
 542 */
 543        gbyte(in,&something,&skip,24);
 544        DPRINT0 ("Sign & gds->lam.lLat1\n");
 545        sign = (int)(something >> 23) & 1;                   /* get sign */
 546        gds->lam.lLat1 = (long)  (something) & 8388607;      /* get La1 */
 547        if(sign)                                             /* negative value */
 548           gds->lam.lLat1 = - gds->lam.lLat1;                /* multiply by -1 */
 549
 550 /*
 551 *                 FUNCTION gbyte !get Longitude of First Point
 552 */
 553        gbyte(in,&something,&skip,24);
 554        DPRINT0 ("Sign & gds->lam.lLon1)\n");
 555        sign = (int)(something >> 23) & 1;                   /* get sign */
 556        gds->lam.lLon1 = (long) (something) & 8388607;       /* get Lo1 */
 557        if(sign)                                             /* negative value */
 558           gds->lam.lLon1 = - gds->lam.lLon1;                /* multiply by -1 */
 559
 560 /*
 561 *                 FUNCTION gbyte !get resolution & comp flag
 562 */
 563        gbyte(in,&something,&skip,8);
 564        DPRINT0 ("gds->lam.usRes_flag\n");
 565        gds->lam.usRes_flag = (short) something;  /* resolution & comp flags */
 566
 567 /*
 568 *                 FUNCTION gbyte !get Orientation Longitude
 569 */
 570        gbyte(in,&something,&skip,24);
 571        DPRINT0 ("Sign & gds->lam.lLon_orient)\n");
 572        sign = (int)(something >> 23) & 1;                    /* get sign */
 573        gds->lam.lLon_orient = (long) (something) & 8388607;  /* Orientation */
 574        if(sign)              /* negative value , multiply by -1 */
 575           gds->lam.lLon_orient = - gds->lam.lLon_orient;
 576
 577 /*
 578 *                 FUNCTION gbyte !get Increment along a Row
 579 */
 580        gbyte(in,&something,&skip,24);
 581        DPRINT0 ("gds->lam.ulDx\n");
 582        gds->lam.ulDx = (float) something;                    /* get Dx */
 583
 584 /*
 585 *                 FUNCTION gbyte !get Increment along a Column
 586 */
 587        gbyte(in,&something,&skip,24);
 588        DPRINT0 ("gds->lam.ulDy\n");
 589        gds->lam.ulDy = (float) something;                    /* get Dy */
 590
 591 /*
 592 *                 FUNCTION gbyte !get Projection Center
 593 */
 594        gbyte(in,&something,&skip,8);
 595        DPRINT0 ("gds->lam.usProj_flag\n");
 596        gds->lam.usProj_flag= (short) something;  /* Projection center flag */
 597
 598 /*
 599 *                 FUNCTION gbyte !get scanning mode flag
 600 */
 601        gbyte(in,&something,&skip,8);
 602        DPRINT0 ("gds->usScan_mode\n");
 603        gds->lam.usScan_mode = (short) something;    /* get scaning mode flag */
 604
 605 /*
 606 *                 FUNCTION gbyte !get First lat from pole that intersects Earth
 607 */
 608        gbyte(in,&something,&skip,24);
 609        DPRINT0 ("gds->lLat_cut1\n");
 610        gds->lam.lLat_cut1 = (long) something;                /* get latin_1 */
 611
 612 /*
 613 *                 FUNCTION gbyte !get Second lat from pole that intersects Earth
 614 */
 615        gbyte(in,&something,&skip,24);
 616        DPRINT0 ("gds->lLat_cut2\n");
 617        gds->lam.lLat_cut2 = (long) something;                /* get latin_2 */
 618
 619 /*
 620 *                 FUNCTION gbyte !get lat of south pole
 621 */
 622        gbyte(in,&something,&skip,24);
 623        DPRINT0 ("Sign & gds->lLat_southpole\n");
 624        sign = (int)(something >> 23) & 1;                        /* get sign */
 625        gds->lam.lLat_southpole = (long) (something) & 8388607;   /* lat S.pole*/
 626        if(sign)      /* negative value , multiply by -1 */
 627            gds->lam.lLat_southpole = - gds->lam.lLat_southpole;
 628
 629 /*
 630 *                 FUNCTION gbyte !get lon of South pole
 631 */
 632        gbyte(in,&something,&skip,24);
 633        DPRINT0 ("Sign & gds->lLon_southpole\n");
 634        sign = (int)(something >> 23) & 1;                        /* get sign */
 635        gds->lam.lLon_southpole = (long) (something) & 8388607;/* lon S.pole */
 636        if(sign)     /* negative value, multiply by -1 */
 637            gds->lam.lLon_southpole = - gds->lam.lLon_southpole;
 638
 639 /*
 640 *                 FUNCTION gbyte !get Reserved zero
 641 */
 642        gbyte(in,&something,&skip,16);
 643        DPRINT0 ("gds->lam.usZero\n");
 644        gds->lam.usZero = (int) something;                    /* Reserved zero */
 645
 646        gds->head.thin = NULL;
 647
 648        if (gds->lam.iNx == 65535) {
 649          gds->head.thin = (int *)calloc(gds->lam.iNy,sizeof(int));
 650          if (gds->head.thin == NULL) {
 651            sprintf(errmsg,
 652                    "%s: failed to create array[%d] for thinned grid information",
 653                    func, gds->head.thin);
 654            goto BYE;
 655          }
 656          for (i = 0; i<gds->lam.iNy; i++) {
 657            gbyte(in,&something,&skip,16);
 658            gds->head.thin[i] = (short)something;
 659          }
 660        } else {
 661          gds->head.thin = NULL;
 662        }
 663
 664        break;
 665
 666     default :             /* other cases not implemented in this version */
 667 /*
 668 *             default:   ! unsupported data types
 669 *                 SET Status to bad
 670 */
 671        DPRINT2 ("%s:  unknown datatype=%d\n",func, gds->head.usData_type);
 672        sprintf(errmsg,"%s:  unknown datatype=%d\n",func, gds->head.usData_type);
 673        status=1;         /* set status to failure */
 674        break;
 675 /*
 676 *
 677 * A.5      ENDSWITCH
 678 */
 679   }  /* end switch on data type */
 680
 681 /*
 682 *
 683 * A.6      DEBUG Print
 684 *
 685 * A.7      RETURN (status)
 686 */
 687  BYE:
 688   DPRINT2 ("Exiting %s, stat=%d\n", func,status);
 689   return(status);
 690 /*
 691 *  END OF FUNCTION
 692 *
 693 */
 694 }