collocate's Introduction

collocate

collocate un-structured xarray DataArray's (or Iris Cube's) in arbitrary physical dimensions.

For example, taking a dataset with mutli-dimensional latitude and longitude coordinates

>>> da
 <xarray.DataArray (x: 5, y: 3)>
array([[ 0,  1,  2],
       [ 3,  4,  5],
       [ 6,  7,  8],
       [ 9, 10, 11],
       [12, 13, 14]])
Coordinates:
    longitude  (x, y) float64 -10.0 -10.0 -10.0 -5.0 -5.0 -5.0 0.0 0.0 0.0 ...
    latitude   (x, y) float64 -5.0 0.0 5.0 -5.0 0.0 5.0 -5.0 0.0 5.0 -5.0 ...
Dimensions without coordinates: x, y

And a set of arbitrary points

>> points
<xarray.DataArray (obs: 3)>
array([ 0.,  0.,  0.])
Coordinates:
    latitude   (obs) float64 0.5 5.4 12.0
    longitude  (obs) float64 -0.7 0.2 3.0
Dimensions without coordinates: obs

We can perform a collocation to find the mean value of the data with 500km of each sample point like so

>>> collocate(points, da, h_sep=500)
 
<xarray.Dataset>
Dimensions:    (obs: 3)
Coordinates:
  * obs        (obs) int64 0 1 2
Data variables:
    latitude   (obs) float64 0.5 5.4 12.0
    longitude  (obs) float64 -0.7 0.2 3.0
    var        (obs) float64 5.5 8.0 nan

Note this is still a prototype and the API is likely to change!