cfdm.DomainTopology.sort

DomainTopology.sort()[source]

Sort the domain topology node ids.

Only edge and point domain topologies can be sorted.

Sorting is across both array dimensions. In general, dimension 1 is sorted first, and then dimension 0 is sorted by the values in the first column.

For an edge domain topology, the second column is also sorted within each unique first column value.

For a point dimension topology, the first column is omitted from the dimension 1 sort (because it contains the node id definition for each row).

See the examples for more details.

Note

The purpose of this method is to facilitate the comparison of normalised domain topologies, to see if they belong to the same UGRID mesh. The sorted domain topology will, in general, be inconsistent with other metadata, such as the node geo-locations stored as domain cell coordinates or cell bounds. For this reason, sort is not allowed to occur in-place.

Added in version (cfdm): 1.13.1.0

See also

normalise, to_edge

Returns:
DomainTopology

The sorted domain topology construct.

Examples

>>> f = cfdm.example_field(9)
>>> print(f)
Field: northward_wind (ncvar%v)
-------------------------------
Data            : northward_wind(time(2), ncdim%nMesh2_edge(9)) ms-1
Cell methods    : time(2): point (interval: 3600 s)
Dimension coords: time(2) = [2016-01-02 01:00:00, 2016-01-02 11:00:00] gregorian
Auxiliary coords: longitude(ncdim%nMesh2_edge(9)) = [-41.5, ..., -43.0] degrees_east
                : latitude(ncdim%nMesh2_edge(9)) = [34.5, ..., 32.0] degrees_north
Topologies      : cell:edge(ncdim%nMesh2_edge(9), 2) = [[1, ..., 5]]
Connectivities  : connectivity:node(ncdim%nMesh2_edge(9), 6) = [[0, ..., --]]
>>> dt = f.domain_topology()
>>> print(dt.array)
[[1 6]
 [3 6]
 [3 1]
 [0 1]
 [2 0]
 [2 3]
 [2 4]
 [5 4]
 [3 5]]
>>> print(dt.sort().array)
[[0 1]
 [0 2]
 [1 3]
 [1 6]
 [2 3]
 [2 4]
 [3 5]
 [3 6]
 [4 5]]

>>> f = cfdm.example_field(10)
>>> print(f)
Field: air_pressure (ncvar%pa)
------------------------------
Data            : air_pressure(time(2), ncdim%nMesh2_node(7)) hPa
Cell methods    : time(2): point (interval: 3600 s)
Dimension coords: time(2) = [2016-01-02 01:00:00, 2016-01-02 11:00:00] gregorian
Auxiliary coords: longitude(ncdim%nMesh2_node(7)) = [-45.0, ..., -40.0] degrees_east
                : latitude(ncdim%nMesh2_node(7)) = [35.0, ..., 34.0] degrees_north
Topologies      : cell:point(ncdim%nMesh2_node(7), 5) = [[0, ..., --]]
>>> dt = f.domain_topology()
>>> dt = dt[::-1]
>>> print(dt.array)
[[6 3 1 -- --]
 [5 4 3 -- --]
 [4 2 5 -- --]
 [3 2 1 5 6]
 [2 0 3 4 --]
 [1 6 0 3 --]
 [0 1 2 -- --]]
>>> print(dt.sort().array)
[[0 1 2 -- --]
 [1 0 3 6 --]
 [2 0 3 4 --]
 [3 1 2 5 6]
 [4 2 5 -- --]
 [5 3 4 -- --]
 [6 1 3 -- --]]