int codes_grib_iterator_reset(grib_iterator *i)
{
return grib_iterator_reset(i);
}
static int find(grib_nearest* nearest, grib_handle* h,
double inlat, double inlon,unsigned long flags,
double* outlats,double* outlons,
double *values,double *distances,int* indexes, size_t *len)
{
grib_nearest_lambert_conformal* self = (grib_nearest_lambert_conformal*) nearest;
int ret=0, i=0;
size_t nvalues=0;
long iradius;
double radius;
grib_iterator* iter=NULL;
double lat=0,lon=0;
/* array of candidates for nearest neighbours */
PointStore* neighbours = NULL;
while (inlon<0) inlon+=360;
while (inlon>360) inlon-=360;
if( (ret = grib_get_size(h,self->values_key,&nvalues))!= GRIB_SUCCESS)
return ret;
nearest->values_count = nvalues;
if (grib_is_missing(h,self->radius,&ret)) {
grib_context_log(h->context, GRIB_LOG_DEBUG,"Key '%s' is missing", self->radius);
return ret ? ret : GRIB_GEOCALCULUS_PROBLEM;
}
if( (ret = grib_get_long(h,self->radius,&iradius))!= GRIB_SUCCESS)
return ret;
radius=((double)iradius)/1000.0;
neighbours = (PointStore*)grib_context_malloc( nearest->context, nvalues*sizeof(PointStore) );
for(i=0; i<nvalues; ++i) {
neighbours[i].m_dist = 1e10; /* set all distances to large number to begin with */
neighbours[i].m_lat=0;
neighbours[i].m_lon=0;
neighbours[i].m_value=0;
neighbours[i].m_index=0;
}
/* GRIB_NEAREST_SAME_GRID not yet implemented */
{
double the_value = 0;
double min_dist = 1e10;
size_t the_index = 0;
int ilat=0, ilon=0;
int idx_upper=0, idx_lower=0;
double lat1=0, lat2=0; /* inlat will be between these */
double dist=0;
const double LAT_DELTA = 10.0; /* in degrees */
if (grib_is_missing(h,self->Ni,&ret)) {
grib_context_log(h->context, GRIB_LOG_DEBUG,"Key '%s' is missing", self->Ni);
return ret ? ret : GRIB_GEOCALCULUS_PROBLEM;
}
if (grib_is_missing(h,self->Nj,&ret)) {
grib_context_log(h->context, GRIB_LOG_DEBUG,"Key '%s' is missing", self->Nj);
return ret ? ret : GRIB_GEOCALCULUS_PROBLEM;
}
self->lons_count=nvalues; /* Maybe overestimate but safe */
self->lats_count=nvalues;
if (self->lats) grib_context_free(nearest->context,self->lats);
self->lats=(double*)grib_context_malloc( nearest->context, nvalues* sizeof(double));
if (!self->lats) return GRIB_OUT_OF_MEMORY;
if (self->lons) grib_context_free(nearest->context,self->lons);
self->lons=(double*)grib_context_malloc( nearest->context, nvalues*sizeof(double));
if (!self->lons) return GRIB_OUT_OF_MEMORY;
iter=grib_iterator_new(h,0,&ret);
if (ret) return ret;
/* First pass: collect all latitudes and longitudes */
while(grib_iterator_next(iter,&lat,&lon,&the_value))
{
++the_index;
Assert(ilat < self->lats_count);
Assert(ilon < self->lons_count);
self->lats[ilat++]=lat;
self->lons[ilon++]=lon;
}
/* See between which 2 latitudes our point lies */
qsort(self->lats, nvalues, sizeof(double), &compare_doubles_ascending);
grib_binary_search(self->lats, self->lats_count-1, inlat, &idx_upper, &idx_lower);
lat2 = self->lats[idx_upper];
lat1 = self->lats[idx_lower];
Assert(lat1<=lat2);
/* Second pass: Iterate again and collect candidate neighbours */
grib_iterator_reset(iter);
the_index=0;
i = 0;
while(grib_iterator_next(iter,&lat,&lon,&the_value))
{
if (lat > lat2+LAT_DELTA || lat < lat1-LAT_DELTA) {
/* Ignore latitudes too far from our point */
}
else {
dist = grib_nearest_distance(radius, inlon, inlat, lon, lat);
if (dist < min_dist) min_dist = dist;
/*printf("Candidate: lat=%.5f lon=%.5f dist=%f Idx=%ld Val=%f\n",lat,lon,dist,the_index,the_value);*/
/* store this candidate point */
neighbours[i].m_dist = dist;
neighbours[i].m_index = the_index;
neighbours[i].m_lat = lat;
neighbours[i].m_lon = lon;
neighbours[i].m_value = the_value;
i++;
}
++the_index;
}
/* Sort the candidate neighbours in ascending order of distance */
/* The first 4 entries will now be the closest 4 neighbours */
qsort(neighbours, nvalues, sizeof(PointStore), &compare_points);
grib_iterator_delete(iter);
}
nearest->h=h;
/* Sanity check for sorting */
#ifdef DEBUG
for(i=0; i<nvalues-1; ++i) {
Assert( neighbours[i].m_dist <= neighbours[i+1].m_dist);
}
#endif
/* GRIB_NEAREST_SAME_XXX not yet implemented */
if (!self->distances) {
self->distances=(double*)grib_context_malloc( nearest->context,4*sizeof(double));
}
self->distances[0] = neighbours[0].m_dist;
self->distances[1] = neighbours[1].m_dist;
self->distances[2] = neighbours[2].m_dist;
self->distances[3] = neighbours[3].m_dist;
for(i=0; i <4; ++i)
{
distances[i] = neighbours[i].m_dist;
outlats[i] = neighbours[i].m_lat;
outlons[i] = neighbours[i].m_lon;
indexes[i] = neighbours[i].m_index;
values[i] = neighbours[i].m_value;
/*printf("(%f,%f) i=%d d=%f v=%f\n",outlats[i],outlons[i],indexes[i],distances[i],values[i]);*/
}
free(neighbours);
return GRIB_SUCCESS;
}
