harmonica.filters.derivative_upward_kernel
harmonica.filters.derivative_upward_kernel¶
- harmonica.filters.derivative_upward_kernel(fft_grid, order=1)[source]¶
Filter for upward derivative in frequency domain
Return a
xarray.DataArraywith the values of the frequency domain filter for computing the upward derivative. The filter is built upon the frequency coordinates of the passedfft_gridand is defined as follows:\[g(\mathbf{k}) = |\mathbf{k}| ^ n\]where \(\mathbf{k}\) is the wavenumber vector (\(\mathbf{k} = 2\pi \mathbf{f}\) where \(\mathbf{f}\) is the frequency vector) and \(n\) is the order of the derivative.
- Parameters
fft_grid (
xarray.DataArray) – Array with the Fourier transform of the original grid. Its dimensions should be in the following order: freq_northing, freq_easting. Usexrft.xrft.fftandxrft.xrft.ifftfunctions to compute the Fourier Transform and its inverse, respectively.order (int) – The order of the derivative. Default to 1.
- Returns
da_filter (
xarray.DataArray) – Array with the kernel for the upward derivative filter in frequency domain.
References
See also