improver.cli.neighbour_finding module
Script to create neighbour cubes for extracting spot data.
- process(orography, land_sea_mask, site_list, *, all_methods=False, land_constraint=False, similar_altitude=False, search_radius=None, node_limit=None, site_coordinate_system=None, site_coordinate_options=None, site_x_coordinate=None, site_y_coordinate=None, unique_site_id_key=None)[source]
Create neighbour cubes for extracting spot data.
Determine grid point coordinates within the provided cubes that neighbour spot data sites defined within the provided JSON/Dictionary. If no options are set the returned cube will contain the nearest neighbour found for each site. Other constrained neighbour finding methods can be set with options below. 1. Nearest neighbour. 2. Nearest land point neighbour. 3. Nearest neighbour with minimum height difference. 4. Nearest land point neighbour with minimum height difference.
- Parameters:
orography (iris.cube.Cube) – Cube of model orography for the model grid on which neighbours are being found.
land_sea_mask (iris.cube.Cube) – Cube of model land mask for the model grid on which neighbours are being found, with land points set to one and sea points set to zero.
site_list (dict) – Dictionary that contains the spot sites for which neighbouring grid points are to be found.
all_methods (bool) – If True, this will return a cube containing the nearest grid point neighbours to spot sites as defined by each possible combination of constraints.
land_constraint (bool) – If True, this will return a cube containing the nearest grid point neighbours to spot sites that are also land points. May be used with the similar_altitude option.
similar_altitude (bool) – If True, this will return a cube containing the nearest grid point neighbour to each spot site that is found, within a given search radius, to minimise the height difference between the two. May be used with the land_constraint option.
search_radius (float) – The radius in metres about a spot site within which to search for a grid point neighbour that is land or which has a smaller height difference than the nearest.
node_limit (int) – When searching within the defined search_radius for suitable neighbours, a KDTree is constructed. This node_limit prevents the tree from becoming too large for large search radii. A default of 36 will be set, which is to say the nearest 36 grid points will be considered. If the search radius is likely to contain more than 36 points, this value should be increased to ensure all point are considered.
site_coordinate_system (cartopy coordinate system) – The coordinate system in which the site coordinates are provided within the site list. This must be provided as the name of a cartopy coordinate system. The Default will become PlateCarree.
site_coordinate_options (str) – JSON formatted string of options passed to the cartopy coordinate system given in site_coordinate_system. “globe” is handled as a special case to construct a cartopy Globe object.
site_x_coordinate (str) – The key that identifies site x coordinates in the provided site dictionary. Defaults to longitude.
site_y_coordinate (str) – The key that identifies site y coordinates in the provided site dictionary. Defaults to latitude.
unique_site_id_key (str) – Key in the provided site list that corresponds to a unique numerical ID for every site (up to 8 digits). If this optional key is provided such an identifier must exist for every site. This key will be used as the name for an additional coordinate on the returned neighbour cube. Values in this coordinate will be recorded as strings, with all numbers padded to 8-digits, e.g. “00012345”.
- Returns:
The processed Cube.
- Return type:
- Raises:
ValueError – If all_methods is used with land_constraint or similar_altitude.