xarray.Dataset.traj.transform

Dataset.traj.transform(to_crs)

Transform this datasets to to_crs coordinate system. If the target projection is not a geographic coordinate system the variables will be named x and y, otherwise lon and lat.

Parameters:

to_crs (pyproj.crs.CRS)

Returns:

ds (array-like) – Dataset in to_crs coordinate system.

Example

Transform dataset to UTM coordinates:

>>> import xarray as xr
>>> import trajan as _
>>> import lzma
>>> import pyproj
>>> b = lzma.open('examples/barents.nc.xz')
>>> ds = xr.open_dataset(b)
>>> print(ds)
<xarray.Dataset> Size: 110kB
Dimensions:        (trajectory: 2, obs: 2287)
Dimensions without coordinates: trajectory, obs
Data variables:
    lon            (trajectory, obs) float64 37kB ...
    lat            (trajectory, obs) float64 37kB ...
    time           (trajectory, obs) datetime64[ns] 37kB ...
    drifter_names  (trajectory) <U16 128B ...
Attributes: (12/13)
    Conventions:          CF-1.10
    featureType:          trajectory
    geospatial_lat_min:   74.5454462
    geospatial_lat_max:   77.4774768
    geospatial_lon_min:   17.2058074
    geospatial_lon_max:   29.8523485
    ...                   ...
    time_coverage_end:    2022-11-23T13:30:28
    creator_email:        gauteh@met.no, knutfd@met.no
    creator_name:         Gaute Hope and Knut Frode Dagestad
    creator_url:          https://github.com/OpenDrift/opendrift
    summary:              Two drifters in the Barents Sea. One stranded at Ho...
    title:                Barents Sea drifters

>>> crs = pyproj.CRS.from_epsg(3857) # mercator
>>>
>>> ds_merc = ds.traj.transform(crs)
>>> print(ds_merc)
<xarray.Dataset> Size: 110kB
Dimensions:        (trajectory: 2, obs: 2287)
Dimensions without coordinates: trajectory, obs
Data variables:
    time           (trajectory, obs) datetime64[ns] 37kB ...
    drifter_names  (trajectory) <U16 128B ...
    x              (trajectory, obs) float64 37kB 3.323e+06 ... 2.354e+06
    y              (trajectory, obs) float64 37kB 1.401e+07 ... 1.276e+07
    proj1          float64 8B nan
Attributes: (12/13)
    Conventions:          CF-1.10
    featureType:          trajectory
    geospatial_lat_min:   74.5454462
    geospatial_lat_max:   77.4774768
    geospatial_lon_min:   17.2058074
    geospatial_lon_max:   29.8523485
    ...                   ...
    time_coverage_end:    2022-11-23T13:30:28
    creator_email:        gauteh@met.no, knutfd@met.no
    creator_name:         Gaute Hope and Knut Frode Dagestad
    creator_url:          https://github.com/OpenDrift/opendrift
    summary:              Two drifters in the Barents Sea. One stranded at Ho...
    title:                Barents Sea drifters

See also

transformer, crs