Evaluate a real function expressed in real spherical harmonics at a single point.

## Usage

value = MakeGridPoint (cilm, lmax, lat, lon, norm, csphase, dealloc)

## Parameters

value : output, real*8
Value of the function at (lat, lon).
cilm : input, real*8, dimension (2, lmax+1, lmax+1)
The real spherical harmonic coefficients of the function. The coefficients C1lm and C2lm refer to the cosine (Clm) and sine (Slm) coefficients, respectively, with Clm=cilm(1,l+1,m+1) and Slm=cilm(2,l+1,m+1).
lmax : input, integer
The maximum spherical harmonic degree used in evaluating the function.
lat : input, real*8
The latitude of the point in DEGREES.
lon : input, real*8
The longitude of the point in DEGREES.
norm : input, optional, integer, default = 1
1 (default) = Geodesy 4-pi normalized harmonics; 2 = Schmidt semi-normalized harmonics; 3 = unnormalized harmonics; 4 = orthonormal harmonics.
csphase : input, optional, integer, default = 1
1 (default) = do not apply the Condon-Shortley phase factor to the associated Legendre functions; -1 = append the Condon-Shortley phase factor of (-1)^m to the associated Legendre functions.
dealloc : input, optional, integer, default = 0
0 (default) = Save variables used in the external Legendre function calls. (1) Deallocate this memory at the end of the funcion call.

## Description

MakeGridPoint will expand a function expressed in spherical harmonics at a single point. The input latitude and longitude are in degrees. The employed spherical harmonic normalization and Condon-Shortley phase convention can be set by the optional arguments norm and csphase; if not set, the default is to use geodesy 4-pi normalized harmonics that exclude the Condon-Shortley phase of (-1)^m.