Datasets

ClimateTools uses YAXArrays for reading and manipulating gridded data.

Open a Dataset

using YAXArrays

cube = Cube(open_dataset("data.nc"))

Subset by Dimension

Use DimensionalData selectors directly:

using DimensionalData

sub = cube[Dim{:time}(DateTime(1980,1,1)..DateTime(2009,12,31))]

Spatial Selection

Spatial operations in ClimateTools assume coordinate dimensions are available on the cube. For irregular grids, use the regridding functions documented in interpolation.

Polygon Subsetting with spatialsubset

Use spatialsubset to crop and mask a cube with a polygon in lon/lat coordinates. The polygon can be provided as 2xN or Nx2.

using ClimateTools
using YAXArrays

cube = Cube(open_dataset("data.nc"))

# Coordinates are [lon; lat], NaN starts a polygon segment.
poly = [NaN -80.0 -72.0 -72.0 -80.0 -80.0;
        NaN  45.0  45.0  50.0  50.0  45.0]

sub = spatialsubset(cube, poly)

With shapefiles:

using ClimateTools

poly = ClimateTools.extractpoly("region.shp", n=1)
sub = spatialsubset(cube, poly)

Notes:

• spatialsubset returns a lazily-evaluated YAXArray with a bounding-box crop and polygon mask applied.
• The input cube is not fully loaded in memory for subsetting.
• The function supports longitude coordinates in either -180..180 or 0..360 conventions.
• If the polygon does not overlap the grid, an error is raised.