Compute the latitudinal weights used in the Driscoll and Healy (1994) spherical harmonic transform.

## Usage

`aj`

= DHaj (`n`

)

## Returns

`aj`

: float, dimension (`n`

)- The latitudinal weights used in the spherical harmonic transform.

## Parameters

`n`

: integer- The number of samples in latitude used in the spherical harmonic transform. This must be even.

## Description

`DHaj`

will calculate the latitudinal weights used in the spherical harmonic transform of Driscoll and Healy (1994; equation 9). The number of samples `n`

must be even, and the transform and its inverse are implemented as `SHExpandDH`

and `MakeGridDH`

, respectively. It is noted that the first element, corresponding to the north pole, is always zero. The element corresponding to the south pole is not included.

## Reference

Driscoll, J.R. and D.M. Healy, Computing Fourier transforms and convolutions on the 2-sphere, Adv. Appl. Math., 15, 202-250, 1994.

## See also

shexpanddh, makegriddh, shexpanddhc, makegriddhc

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