proj2ell.m

Set of tools to perform transformations between projection, ellipsoidal and cartesian coordinates in

function ELL=proj2ell(PRO,sys,UND)

% PROJ2ELL performs transformation from a mapping projection to ellipsoidal coordinates
%
% ELL=proj2ell(PRO,sys,UND)
%
% Also necessary:   Projections.mat   Ellipsoids.mat   (see beneath)
%
% Inputs:  PRO coordinates in projection system as nx2-matrix (abscissa and ordinate vaules).
%              2xn-matrices are allowed. Be careful with 2x2-matrices!
%              If for (some) points orthometric height is available, PRO may be a nx3-matrix also.
%          sys is the projection system type as string in lower case letters
%              Default is 'gk'.
%              Information about the projection systems is stored in the mat-File "Projections.mat"
%              which has cell-array members named by the projection type, e.g. 'gk' or 'utm' for
%              Gauss-Kruger or UTM projection.
%              The projection cell array fields are
%                   m0  the scaling factor of the central meridian
%               ellips  the underlying ellipsoid as string in lower case letters
%                       The ellipsoids are stored in the mat-File "Ellipsoids.mat" also as
%                       cell-arrays named by the ellipsoid, e.g. 'bessel1841' or 'wgs84'.
%                       The ellipsoid cell array fields are
%                         a  semimajor axis
%                         b  semiminor axis
%                         f  flattening
%               ruleEll the rule to translate the zone identifier ID for the projection zone to
%                       longitude (used in this m-file)
%                       The zone identifier is taken from the abscissa coordinate of the projection 
%                       and is transformed into a addition on the calculated longitude-per-zone.
%                       For example, for GK-projection the rule is "+ID*3" due to 3