int cyclic(unsigned char **sec) {
int grid_template, nx, ny, res, scan, flag_3_3, no_dx, basic_ang, sub_ang;
unsigned int npnts;
unsigned char *gds;
double dlon, units, lon1, lon2;
get_nxny(sec, &nx, &ny, &npnts, &res, &scan);
if (GDS_Scan_staggered(scan)) return 0;
if (nx <= 1 || ny <= 0) return 0;
grid_template = code_table_3_1(sec);
gds = sec[3];
flag_3_3 = flag_table_3_3(sec);
no_dx = 0;
if (flag_3_3 != -1) {
if ((flag_3_3 & 0x20) == 0) no_dx = 1;
}
if (no_dx) return 0;
if (grid_template == 0) {
basic_ang = GDS_LatLon_basic_ang(gds);
sub_ang = GDS_LatLon_sub_ang(gds);
units = basic_ang == 0 ? 0.000001 : (double) basic_ang / (double) sub_ang;
/* dlon has to be defined */
dlon = units * GDS_LatLon_dlon(gds);
return (fabs(nx*dlon-360.0) < ERROR);
}
if (grid_template == 10) {
if (output_order != wesn) return 0; // only works with we:sn order
lon1 = GDS_Mercator_lon1(gds);
lon2 = GDS_Mercator_lon2(gds);
if (lon2 < lon1) lon2 += 360.0;
dlon = (lon2-lon1)*nx/(nx-1.0);
return (fabs(dlon-360.0) < ERROR);
}
if (grid_template == 40) {
basic_ang = GDS_Gaussian_basic_ang(gds);
sub_ang = GDS_Gaussian_sub_ang(gds);
units = basic_ang == 0 ? 0.000001 : (double) basic_ang / (double) sub_ang;
/* dlon has to be defined */
dlon = units * GDS_Gaussian_dlon(gds);
return (fabs(nx*dlon-360.0) < ERROR);
}
return 0;
}
int cyclic(unsigned char **sec) {
int grid_template, nx, ny, res, scan, flag_3_3, no_dx, basic_ang, sub_ang;
unsigned int npnts;
unsigned char *gds;
double dlon, units;
get_nxny(sec, &nx, &ny, &npnts, &res, &scan);
if ((unsigned) (nx * ny) != npnts) return 0;
if (nx <= 0 || ny <= 0) return 0;
grid_template = code_table_3_1(sec);
gds = sec[3];
flag_3_3 = flag_table_3_3(sec);
no_dx = 0;
if (flag_3_3 != -1) {
if ((flag_3_3 & 0x20) == 0) no_dx = 1;
}
if (grid_template == 0) {
basic_ang = GDS_LatLon_basic_ang(gds);
sub_ang = GDS_LatLon_sub_ang(gds);
units = basic_ang == 0 ? 0.000001 : (double) basic_ang / (double) sub_ang;
dlon = units * GDS_LatLon_dlon(gds);
if (no_dx) dlon = 0.0;
dlon = nx * dlon;
return (fabs(dlon-360.0) < ERROR);
}
if (grid_template == 10) {
dlon = GDS_Mercator_dx(gds);
if (no_dx) dlon = 0.0;
dlon = nx * dlon;
return (fabs(dlon-360.0) < ERROR);
}
// need to add gaussian grid - a bit more complicated
return 0;
}
int regular2ll(unsigned char **sec, double **lat, double **lon) {
int basic_ang, sub_ang;
double units, dlat, dlon, lat1, lat2, lon1, lon2;
double e, w, n, s, dx, dy;
int i, j;
double *llat, *llon;
unsigned char *gds;
int nnx, nny, nres, nscan;
unsigned int nnpnts;
get_nxny(sec, &nnx, &nny, &nnpnts, &nres, &nscan);
gds = sec[3];
if (nny == -1) {
fprintf(stderr,"Sorry code does not handle variable ny yet\n");
return 0;
}
if ((*lat = (double *) malloc(nnpnts * sizeof(double))) == NULL) {
fatal_error("regular2ll memory allocation failed","");
}
if ((*lon = (double *) malloc(nnpnts * sizeof(double))) == NULL) {
fatal_error("regular2ll memory allocation failed","");
}
/* now figure out the grid coordinates mucho silly grib specification */
basic_ang = GDS_LatLon_basic_ang(gds);
sub_ang = GDS_LatLon_sub_ang(gds);
if (basic_ang != 0) {
units = (double) basic_ang / (double) sub_ang;
}
else {
units = 0.000001;
}
dlat = GDS_LatLon_dlat(gds) * units;
dlon = GDS_LatLon_dlon(gds) * units;
lat1 = GDS_LatLon_lat1(gds) * units;
lat2 = GDS_LatLon_lat2(gds) * units;
lon1 = GDS_LatLon_lon1(gds) * units;
lon2 = GDS_LatLon_lon2(gds) * units;
if (lon1 < 0.0 || lon2 < 0.0) fatal_error("BAD grid definition lon < zero","");
if (lon1 > 360.0 || lon2 > 360.0) fatal_error("BAD grid definition lon >= 360","");
if (lat1 < -90.0 || lat2 < -90.0 || lat1 > 90.0 || lat2 > 90.0) fatal_error("BAD grid definition lat","");
/* find S latitude and dy */
if (GDS_Scan_y(nscan)) {
s = lat1;
n = lat2;
}
else {
s = lat2;
n = lat1;
}
if (s > n) fatal_error("lat-lon grid: lat1 and lat2 inconsistent with scan order","");
if (nny != 1) {
dy = (n - s) / (nny - 1);
if (nres & 16) { /* lat increment is valid */
if (fabs(dy - dlat) > 0.001) fatal_error("lat-lon grid: dlat is inconsistent","");
}
}
else {
dy = 0.0;
}
// fprintf(stderr,">>> geo: dy %lf dlat %lf nres %d has dy %d has dx %d\n", dy, dlat, nres, nres & 16, nres & 32);
/* find W latitude and dx */
if ( GDS_Scan_row_rev(nscan) && (nny % 2 == 0) && ((nres & 32) == 0) ) {
fatal_error("grib GDS ambiguity","");
}
if (GDS_Scan_x(nscan)) {
w = lon1;
e = lon2;
if (GDS_Scan_row_rev(nscan) && ((nres & 32) == 0)) {
e = lon1 + (nnx-1) * dlon;
}
} else {
w = lon2;
e = lon1;
if (GDS_Scan_row_rev(nscan) && ((nres & 32) == 0)) {
w = lon1 - (nnx-1) * dlon;
}
}
if (e <= w) e += 360.0;
if (e-w > 360.0) e -= 360.0;
if (w < 0) {
w += 360.0;
e += 360.0;
}
/* lat-lon should be in a WE:SN order */
if (nnx > 0 && nny > 0) { /* non-thinned, potentially staggered grid */
/* put x[] and y[] values in lon[] and lat[] */
llat = *lat;
llon = *lon;
if (stagger(sec, nnpnts,llon,llat)) fatal_error("geo: stagger problem","");
if (nnx != 1) {
dx = (e-w) / (nnx - 1);
dx = fabs(dx);
if (nres & 32) { /* lon increment is valid */
if (fabs(dx - fabs(dlon)) > 0.001) fatal_error("lat-lon grid: dlon is inconsistent","");
}
}
else {
dx = 0.0;
}
dy = fabs(dy);
#pragma omp parallel for private(j)
for (j = 0; j < nnpnts; j++) {
llon[j] = lon1 + llon[j]*dx;
llon[j] = llon[j] >= 360.0 ? llon[j] - 360.0 : llon[j];
llon[j] = llon[j] < 0.0 ? llon[j] + 360.0 : llon[j];
llat[j] = lat1 + llat[j]*dy;
}
return 0;
}
/* must be thinned grid */
llat = *lat;
/* quasi-regular grid */
for (j = 0; j < nny; j++) {
for (i = 0; i < variable_dim[j]; i++) {
*llat++ = s + j*dy;
}
}
llon = *lon;
/* quasi-regular grid */
for (j = 0; j < nny; j++) {
dx = (e-w) / (variable_dim[j]-1);
for (i = 0; i < variable_dim[j]; i++) {
*llon++ = w + i*dx >= 360.0 ? w + i*dx - 360.0: w + i*dx;
}
}
return 0;
} /* end regular2ll() */
