Exemplo n.º 1
0
/* Albers forward equations--mapping lat,long to x,y to line,sample
  ------------------------------------------------------------------*/
int LSalbersfor(
    double *s,    /* O: sample */
    double *l,    /* O: line */
    double lon,   /* I: longitude (degrees) */
    double lat    /* I: latitude (degrees) */
)
{
    int ret = 0;    /* return value */
    double x, y;    /* x,y projection coords */
    double dy, dx;  /* delta x, y */

    /* Convert lat/long from degrees to radians */
    lat *= D2R;
    lon *= D2R;

    /* Do the forward mapping */
    ret = alberfor (lon, lat, &x, &y);
    if (ret != 0)
    {
        printf ("Error in the forward Albers mapping");
        return (ret);
    }

    /* Convert the x,y back to line,sample */
    x -= ul_corner[0];
    y -= ul_corner[1];
    
    dx = (x * cos_orien) + (y * sin_orien);
    dy = (x * sin_orien) - (y * cos_orien);
    
    *s = dx / pixel_size - 0.5;
    *l = dy / pixel_size - 0.5;

    return(0);
}
Exemplo n.º 2
0
int gctpc_get_latlon(unsigned char **sec, double **lon, double **lat) {

    int gdt;
    unsigned char *gds;

    double r_maj;                           /* major axis                   */
    double r_min;                           /* minor axis                   */
    double lat1;                            /* first standard parallel      */
    double lat2;                            /* second standard parallel     */
    double c_lon;                           /* center longitude             */
    double c_lat;                           /* center latitude              */
    double false_east;                      /* x offset in meters           */
    double false_north;
    double dx, dy;
    double x0, y0;
    long int (*inv_fn)();
    double *llat, *llon, rlon, rlat;

    int i, nnx, nny, nres, nscan;
    unsigned int nnpnts;
    long long_i;

    gdt = code_table_3_1(sec);
    gds = sec[3];

    /* only process certain grids */

    if (gdt != 10 && gdt != 20 && gdt != 30 && gdt != 31) return 1;
    get_nxny(sec, &nnx, &nny, &nnpnts, &nres, &nscan);

    /* potentially staggered */
    if (nnx < 1 || nny < 1) return 1;

    llat = *lat;
    llon = *lon;

    if (llat != NULL) {
	free(llat);
	free(llon);
        *lat = *lon = llat = llon = NULL;
    }

    inv_fn = NULL;
    dx = dy = 0.0;

    if (gdt == 10) {            // mercator

       /* get earth axis */
       axes_earth(sec, &r_maj, &r_min);
       dy      = GDS_Mercator_dy(gds);
       dx      = GDS_Mercator_dx(gds);

       /* central point */
       c_lon = GDS_Mercator_ori_angle(gds) * (M_PI/180.0);
       c_lat = GDS_Mercator_latD(gds) * (M_PI/180.0);

       /* find the eastling and northing of of the 1st grid point */

       false_east = false_north = 0.0;
       long_i = merforint(r_maj,r_min,c_lon,c_lat,false_east,false_north);

       rlon   = GDS_Mercator_lon1(gds) * (M_PI/180.0);
       rlat   = GDS_Mercator_lat1(gds) * (M_PI/180.0);

       long_i = merfor(rlon, rlat, &x0, &y0);

       /* initialize for 1st grid point */
       x0 = -x0;
       y0 = -y0;
       long_i = merinvint(r_maj,r_min,c_lon,c_lat,x0,y0);
       inv_fn = &merinv;
    }

    else if (gdt == 20) {            // polar stereographic

       /* get earth axis */
       axes_earth(sec, &r_maj, &r_min);
       dy      = GDS_Polar_dy(gds);
       dx      = GDS_Polar_dx(gds);

       /* central point */
       c_lon = GDS_Polar_lov(gds) * (M_PI/180.0);
       c_lat = GDS_Polar_lad(gds) * (M_PI/180.0);

       /* find the eastling and northing of of the 1st grid point */

       false_east = false_north = 0.0;
       long_i = psforint(r_maj,r_min,c_lon,c_lat,false_east,false_north);

       rlon   = GDS_Polar_lon1(gds) * (M_PI/180.0);
       rlat   = GDS_Polar_lat1(gds) * (M_PI/180.0);

       long_i = psfor(rlon, rlat, &x0, &y0);

       /* initialize for 1st grid point */
       x0 = -x0;
       y0 = -y0;
       long_i = psinvint(r_maj,r_min,c_lon,c_lat,x0,y0);
       inv_fn = &psinv;
    }

    else if (gdt == 30) {            // lambert conformal conic

       /* get earth axis */
       axes_earth(sec, &r_maj, &r_min);
       dy      = GDS_Lambert_dy(gds);
       dx      = GDS_Lambert_dx(gds);
//printf(">>> gctpc dx %lf, dy %lf\n", dx, dy);
       /* latitudes of tangent/intersection */
       lat1 = GDS_Lambert_Latin1(gds) * (M_PI/180.0);
       lat2 = GDS_Lambert_Latin2(gds) * (M_PI/180.0);

       /* central point */
       c_lon = GDS_Lambert_Lov(gds) * (M_PI/180.0);
       c_lat = GDS_Lambert_LatD(gds) * (M_PI/180.0);

       /* find the eastling and northing of of the 1st grid point */

       false_east = false_north = 0.0;
       long_i = lamccforint(r_maj,r_min,lat1,lat2,c_lon,c_lat,false_east,false_north);

       rlon   = GDS_Lambert_Lo1(gds) * (M_PI/180.0);
       rlat   = GDS_Lambert_La1(gds) * (M_PI/180.0);

       long_i = lamccfor(rlon, rlat, &x0, &y0);

       /* initialize for 1st grid point */
       x0 = -x0;
       y0 = -y0;
       long_i = lamccinvint(r_maj,r_min,lat1,lat2,c_lon,c_lat,x0,y0);
       inv_fn = &lamccinv;
    }
    else if (gdt == 31) {			// albers equal area
       /* get earth axis */
       axes_earth(sec, &r_maj, &r_min);
       dy      = GDS_Albers_dy(gds);
       dx      = GDS_Albers_dx(gds);

       /* latitudes of tangent/intersection */
       lat1 = GDS_Albers_Latin1(gds) * (M_PI/180.0);
       lat2 = GDS_Albers_Latin2(gds) * (M_PI/180.0);

       /* central point */
       c_lon = GDS_Albers_Lov(gds) * (M_PI/180.0);
       c_lat = GDS_Albers_LatD(gds) * (M_PI/180.0);

       /* find the eastling and northing of of the 1st grid point */

       false_east = false_north = 0.0;
       long_i = alberforint(r_maj,r_min,lat1,lat2,c_lon,c_lat,false_east,false_north);

       rlon   = GDS_Albers_Lo1(gds) * (M_PI/180.0);
       rlat   = GDS_Albers_La1(gds) * (M_PI/180.0);

       long_i = alberfor(rlon, rlat, &x0, &y0);

       /* initialize for 1st grid point */
       x0 = -x0;
       y0 = -y0;
       long_i = alberinvint(r_maj,r_min,lat1,lat2,c_lon,c_lat,x0,y0);
       inv_fn = &alberinv;
    }
    

    if (inv_fn == NULL)  return 1;

    if ((*lat = llat = (double *) malloc(nnpnts * sizeof(double))) == NULL) {
        fatal_error("gctpc_get_latlon memory allocation failed","");
    }
    if ((*lon = llon = (double *) malloc(nnpnts * sizeof(double))) == NULL) {
        fatal_error("gctpc_get_latlon memory allocation failed","");
    }

    /* put x[] and y[] values in lon and lat */
    if (stagger(sec, nnpnts, llon, llat)) fatal_error("gctpc: stagger problem","");

    printf(">> stagger gctpc x00 %lf y00 %lf\n",llon[0], llat[0]);
#pragma omp parallel for schedule(static) private(i)
    for (i = 0; i < nnpnts; i++) {
        inv_fn(llon[i]*dx, llat[i]*dy, llon+i, llat+i);
	llat[i] *= (180.0 / M_PI);
	llon[i] *= (180.0 / M_PI);
	if (llon[i] < 0.0) llon[i] += 360.0;
    }
    return 0;
}