salem.Grid.lookup_transform

Grid.lookup_transform(data, grid=None, method=<function mean>, lut=None, return_lut=False)

Performs the forward transformation of gridded data into self.

This method is suitable when the data grid is of higher resolution than self. lookup_transform performs aggregation of data according to a user given rule (e.g. np.mean, len, np.std), applied to all grid points found below a grid point in self.

See also Grid.grid_lookup() and examples in the docs

Parameters:

data : ndarray

an ndarray of dimensions 2, 3, or 4, the two last ones being y, x.

grid : Grid

a Grid instance matching the data

method : function, default: np.mean

the aggregation method. Possibilities: np.std, np.median, np.sum, and more. Use len to count the number of grid points!

lut : ndarray, optional

computing the lookup table can be expensive. If you have several operations to do with the same grid, set lut to an existing table obtained from a previous call to Grid.grid_lookup()

return_lut : bool, optional

set to True if you want to return the lookup table for later use. in this case, returns a tuple

Returns:

An aggregated ndarray of the data, in ``self`` coordinates.

If ``return_lut==True``, also return the lookup table