def update_nearest_points(
points_with_mismatches: ndarray,
in_latlons: ndarray,
out_latlons: ndarray,
indexes: ndarray,
distances: ndarray,
surface_type_mask: ndarray,
in_classified: ndarray,
out_classified: ndarray,
) -> Tuple[ndarray, ndarray, ndarray]:
"""
Update nearest source points and distances/surface_type to take into account
surface type of nearby points.
Args:
points_with_mismatches:
Selected target points which will use Inverse Distance Weighting
(idw) approach. These points will be processed by this function.
in_latlons:
Source points's latitude-longitudes.
out_latlons:
Target points's latitude-longitudes.
indexes:
Source grid point indexes for each target grid point.
distances:
Distance from each target grid point to its source grid points.
surface_type_mask:
Boolean true if source point type matches target point type.
in_classified:
Land/sea type for source grid points (land -> True).
out_classified:
Land/sea type for target grid points (land -> True).
Returns:
- Updated indexes - source grid point number for all target grid points.
- Updated distances - array from each target grid point to its source grid points.
- Updated surface_type_mask - matching info between source/target point types.
"""
# Gather output points with mismatched surface type and find four nearest input
# points via KDtree
out_latlons_with_mismatches = out_latlons[points_with_mismatches]
k_nearest = 4
distances_updates, indexes_updates = nearest_input_pts(
in_latlons, out_latlons_with_mismatches, k_nearest)
# Calculate update to surface classification at mismatched points
out_classified_with_mismatches = out_classified[points_with_mismatches]
surface_type_mask_updates = similar_surface_classify(
in_classified, out_classified_with_mismatches, indexes_updates)
# Apply updates to indexes, distances and surface type mask
indexes[points_with_mismatches] = indexes_updates
distances[points_with_mismatches] = distances_updates
surface_type_mask[points_with_mismatches] = surface_type_mask_updates
return indexes, distances, surface_type_mask
def lakes_islands(
lake_island_indexes: ndarray,
indexes: ndarray,
surface_type_mask: ndarray,
in_latlons: ndarray,
out_latlons: ndarray,
in_classified: ndarray,
out_classified: ndarray,
vicinity: float,
) -> Tuple[ndarray, ndarray]:
"""
Updating source points and weighting for 4-unmatching-source-point
cases - water surrounded by land or land surrounded by water.
This function searches nearest 8 points to check if any matching point exists.
Note that a similar function can be found in bilinear.py for bilinear
regridding rather than nearest neighbour regridding.
Args:
lake_island_indexes:
Indexes of points which are lakes/islands surrounded by mismatched surface type.
These points will be processed by this function.
in_latlons:
Source points's latitude-longitudes.
out_latlons:
Target points's latitude-longitudes.
surface_type_mask:
Boolean true if source point type matches target point type.
indexes:
Source grid point indexes for each target grid point.
in_classified:
Land/sea type for source grid points (land -> True).
out_classified:
Land/sea type for target grid points (land -> True).
vicinity:
Radius of vicinity to search for a matching surface type, in metres.
Returns:
- Updated indexes - source grid point number for all target grid points.
- Updated surface_type_mask - matching info between source/target point types.
"""
out_latlons_updates = out_latlons[lake_island_indexes]
# Consider a larger area of 8 nearest points to look for more distant same
# surface type input points.
# more than 8 points are within searching limits not considered here
k_nearest = 8
distances_updates, indexes_updates = nearest_input_pts(
in_latlons, out_latlons_updates, k_nearest)
# Update output surface classification and surface type mask
out_classified_updates = out_classified[lake_island_indexes]
surface_type_mask_updates = similar_surface_classify(
in_classified, out_classified_updates, indexes_updates)
# Where distance is outside specified vicinity, set surface type to be mismatched
# so that it will not be used, update surface type mask again
distance_not_in_vicinity = distances_updates > vicinity
surface_type_mask_updates = np.where(distance_not_in_vicinity, False,
surface_type_mask_updates)
count_matching_surface = np.count_nonzero(surface_type_mask_updates,
axis=1)
points_with_no_match = (np.where(count_matching_surface == 0))[0]
if points_with_no_match.shape[0] > 0:
# No improved input point has been found with the increase to 8 nearest points
# Take the original nearest point, disregard the surface type
no_match_indexes = lake_island_indexes[points_with_no_match]
surface_type_mask[no_match_indexes, :] = True
# From the expansion to 8 nearby input points, a same surface type input has been found
# Update the index and surface type mask to use the newly found same surface type input point
points_with_match = (np.where(count_matching_surface > 0))[0]
count_of_points_with_match = points_with_match.shape[0]
for point_idx in range(count_of_points_with_match):
# Reset all input surface types to mismatched
match_indexes = lake_island_indexes[points_with_match[point_idx]]
surface_type_mask[match_indexes, :] = False
# Loop through 8 nearest points found
for i in range(k_nearest):
# Look for an input point with same surface type as output
if surface_type_mask_updates[points_with_match[point_idx], i]:
# When found, update the indexes and surface mask to use that improved input point
indexes[match_indexes,
0] = indexes_updates[points_with_match[point_idx], i]
surface_type_mask[match_indexes, 0] = True
break
return indexes, surface_type_mask
def lakes_islands(
lake_island_indexes: ndarray,
weights: ndarray,
indexes: ndarray,
surface_type_mask: ndarray,
in_latlons: ndarray,
out_latlons: ndarray,
in_classified: ndarray,
out_classified: ndarray,
in_lons_size: int,
vicinity: float,
lat_spacing: float,
lon_spacing: float,
) -> Tuple[ndarray, ndarray, ndarray]:
"""
Updating source points and weighting for 4-false-source-point cases.
These are lakes (water surrounded by land) and islands (land surrounded by water).
Note that a similar function can be found in nearest.py for nearest
neighbour regridding rather than bilinear regridding.
Args:
lake_island_indexes:
Selected target points which have 4 false source points.
in_latlons:
Source points's latitude-longitudes.
out_latlons:
Target points's latitude-longitudes.
surface_type_mask:
Numpy ndarray of bool, true if source point type matches target point type.
indexes:
Array of source grid point number for all target grid points.
weights:
Array of source grid point weighting for all target grid points.
in_classified:
Land_sea type for source grid points (land ->True).
out_classified:
Land_sea type for terget grid points (land ->True).
in_lons_size:
Source grid's longitude dimension.
vicinity:
Radius of specified searching domain, in meter.
lat_spacing:
Input grid latitude spacing, in degree.
lon_spacing:
Input grid longitude spacing, in degree.
Returns:
- Updated weights - source point weighting for all target grid points.
- Updated indexes - source grid point number for all target grid points.
- Updated surface_type_mask - matching info between source/target point types.
"""
# increase 4 points to 8 points
out_latlons_updates = out_latlons[lake_island_indexes]
# Consider a larger area of 8 nearest points to look for more distant same
# surface type input points
# more than 8 points are within searching limits not considered here
k_nearest = 8
distances_updates, indexes_updates = nearest_input_pts(
in_latlons, out_latlons_updates, k_nearest)
# Update output surface classification and surface type mask
out_classified_updates = out_classified[lake_island_indexes]
surface_type_mask_updates = similar_surface_classify(
in_classified, out_classified_updates, indexes_updates)
# Where distance is outside specified vicinity, set surface type to be mismatched
# so that it will not be used, update surface type mask again
distance_not_in_vicinity = distances_updates > vicinity
surface_type_mask_updates = np.where(distance_not_in_vicinity, False,
surface_type_mask_updates)
count_matching_surface = np.count_nonzero(surface_type_mask_updates,
axis=1)
points_with_no_match = np.where(count_matching_surface == 0)[0]
# If the expanded search area hasn't found any same surface type matches anywhere
# just ignore surface type, use normal bilinear approach
if points_with_no_match.shape[0] > 0:
# revert back to the basic bilinear weights, indexes unchanged
no_match_indexes = lake_island_indexes[points_with_no_match]
weights[no_match_indexes] = basic_weights(
no_match_indexes,
indexes,
out_latlons,
in_latlons,
lat_spacing,
lon_spacing,
)
points_with_match = np.where(count_matching_surface > 0)[0]
count_of_points_with_match = points_with_match.shape[0]
# if no further processing can be done, return early
if count_of_points_with_match == 0:
return weights, indexes, surface_type_mask
# Where a same surface type match has been found among the 8 nearest inputs, apply
# inverse distance weighting with those matched points
new_distances = np.zeros([count_of_points_with_match, NUM_NEIGHBOURS])
for point_idx in range(points_with_match.shape[0]):
match_indexes = lake_island_indexes[points_with_match[point_idx]]
# Reset all input weight and surface type to mismatched
weights[match_indexes, :] = 0.0
surface_type_mask[match_indexes, :] = False
# Loop through 8 nearest points found
good_count = 0
for i in range(k_nearest):
# Look for an input point with same surface type as output
if surface_type_mask_updates[points_with_match[point_idx], i]:
# When found, update the indexes and surface mask to use that improved input point
indexes[match_indexes, good_count] = indexes_updates[
points_with_match[point_idx], i]
surface_type_mask[match_indexes,
good_count] = True # other mask =false
new_distances[point_idx, good_count] = distances_updates[
points_with_match[point_idx], i]
good_count += 1
# Use a maximum of four same surface type input points
# This is kind of like how bilinear uses four nearby input points
if good_count == 4:
break
lake_island_with_match = lake_island_indexes[points_with_match]
# Similar to inverse_distance_weighting in idw.py
not_mask = np.logical_not(surface_type_mask[lake_island_with_match])
masked_distances = np.where(not_mask, np.float32(np.inf), new_distances)
masked_distances += np.finfo(np.float32).eps
inv_distances = 1.0 / masked_distances
# add power 1.80 for inverse diatance weight
inv_distances_power = np.power(inv_distances, OPTIMUM_IDW_POWER)
inv_distances_sum = np.sum(inv_distances_power, axis=1)
inv_distances_sum = 1.0 / inv_distances_sum
weights_idw = inv_distances_power * inv_distances_sum.reshape(-1, 1)
weights[lake_island_with_match] = weights_idw
return weights, indexes, surface_type_mask
