Grid specifications

Implement grid specifications for structured and unstructured grids.

Abstract classes and their attributes:

• Grid: general grid class
  • dim: int: Dimension of the grid
  • crs: The coordinate reference system
  • point_count: Number of grid points
  • cell_count: Number of grid cells
  • points: Grid points
  • cells: Cell nodes in ESMF/VTK order
  • cell_types: int encoding cell types defined in CellType(Enum)
  • cell_centers: Grid cell centers
  • cell_node_counts: node count for each cell
  • mesh_dim: maximal cell dimension
  • data_location: Location of the associated data (either Location.CELLS or Location.POINTS)
  • data_points: Points of the associated data (either cell_centers or points)
  • data_shape: Shape of the associated data
• StructuredGrid(Grid): subclass of Grid for structured data
  • dims: Axes lengths (xyz order) (PyVista naming scheme)
  • axes: list of np.ndarray: Axes of the structured grid in standard xyz order
  • axes_reversed: bool: Indicate reversed axes order for the associated data (zyx order)
    • esri grids and most netcdf files are given in inverse axes order (lat, lon)
  • axes_increase: list of bool: False to indicate a bottom up axis (xyz order)
    • esri grids and some netcdf are given bottom up (northing/lat inverted)
  • axes_attributes: list of dict: Axes attributes following the CF convention (xyz order)
    • should be used for xarray later on
  • axes_names: list of str: Axes names (xyz order)
    • should be used for xarray later on
  • order: str: Point, cell and data order (C- ("C") or Fortran-like ("F"))
    • vtk files use Fortran-like data ordering for structured grids
  • cell_axes: list of np.ndarray: Axes of the cell centers (xyz order)
  • data_axes: list of np.ndarray: Axes as used for the data

Implemented grids so far:

• NoGrid: Indicator for data with no spatial grid
• EsriGrid: representing grids from ascii files
• UniformGrid: representing uniform grids following VTK standard
• RectilinearGrid: representing rectilinear grids following VTK standard
• UnstructuredGrid: representing unstructured grids following VTK standard
• UnstructuredPoints: representing unstructured points without cells