UXarray Dataset & DataArray¶

In this section, you’ll learn:¶

• What are UxDataset and UxDataArray?
• How do they relate to their Xarray counterparts?

Related Documentation¶

• UXarray Data Structures Documentation

Prerequisites¶

Time to learn: 15 minutes

Overview¶

As stated before in this chapter, UxDataset and UxDataArray are the UXarray classes that are inherited from Xarray counterparts and enable to perform analysis and visualization on unstructured mesh datasets.

An instance of UxDataset can be thought of as a collection of data variables, i.e. UxDataArray objects, that reside on a particular unstructured grid as defined in the class property (UxDataset.uxgrid or UxDataArray.uxgrid).

In other words, each of these data structures is linked to its own Grid object through uxgrid to enable grid-awareness, and for UxDataArrays that belong to a specific UxDataset, uxgrid of all of them points to the same Grid object.

Unstructured Mesh Datasets¶

Since most of the unstructured grid datasets contain a single grid definition file along with one or more data files, UXarray’s core API allows to open such datasets using those files.

Let the following dataset have a single data file along with the grid definition:

Loading a UxDataset¶

To open a grid file with a single data file, the uxarray.open_dataset() method can be used. UXarray also provides uxarray.open_mfdataset() for opening multiple data files at once (refer to the UXarray Opening Multipled Data Files Documentation for that), but this notebook will cover only the former.

Grid Accessor¶

Let us first see the Gridobject this dataset object is linked to:

Accessing Data Variables (UxDataArray)¶

Similar to the Xarray conterparts, an UxDataset can have multiple UxDataArrays in it, which are for different data variables. A variable of interest can be accessed in the same way Xarray provides:

Grid Accessor¶

The Gridobject of this data array is the same Grid object as uxds’s above:

Relationship to Xarray¶

For users coming from an Xarray background, much of UXarray’s design is familiar thanks to the UXarray’s inheritance of the core data structures from Xarray’s counterparts and employment of design choices such as accessors. Inheritance has been chosen for the UXarray design both to provide the users with a Xarray-like user experience and to use the built-in Xarray functionality whenever possible while overwrite the others for unstructured grid arithmetic.

As a simple Xarray example that would replicate the above UXarray dataset opening and variable access with UXarray, please see the following code:

What is next?¶

The next section is the final section in this chapter that will provide information about how to operate spatial selection methods on UxDataArray.