Prototype and description of the function setuserellsource()

(Function of the unlock requiring group "User definitions")


Configuration of a geodetic ellipsoid for a user-defined source reference
system or source Coordinate System.

Prototype of the DLL function in C++ syntax (attend lower case!):
extern "C" __declspec(dllimport) unsigned long __stdcall setuserellsource(
     unsigned short nEllipsoid,
     double nMajorSemi,
     double nMinorSemi);

Prototype of the DLL function in Visual Objects syntax:
_DLL function setuserellsource(;
     nEllipsoid as word,;                  // 2 Byte
     nMajorSemi as real8,;                 // 8 Byte
     nMinorSemi as real8);                 // 8 Byte
as logic pascal:geodll32.setuserellsource  // 4 Byte

The function saves the semi axes values of a source ellipsoid for the use
with user-defined Coordinate Transformations and user-defined Reference
System Transition. The number of a pre-defined ellipsoid or the values of
the semi axes can be entered alternatively.

Use of the ellipsoid semi axes:
With the functions coordtrans?(), meritrans(), distance?() and point2point?()
the semi axes values of the source ellipsoid described here are used, if
there is activated an user-defined source Coordinate System or an user-defined
source Reference Systems or an user-defined ellipsoid by passing the values
1000, 1100 or 1150 as flag.

The parameters are passed and/or returned as follows:
nEllipsoid    Flag of the ellipsoid, for which the semi axes are to be
              The ellipsoid numbers are specified at the bottom part of
              the list "Systems sorted alphabetical". The numbers of
              the Reference Systems specified in the list
              "Systems sorted by countries" can be used also.
              If nEllipsoid has value 1000, the user-defined values for
              the two semi axes in nMajorSemi and nMinorSemi are used.

nMajorSemi    Semi-major axis of the source ellipsoid in meters.

nMinorSemi    Semi-minor axis of the source ellipsoid in meters.

returnVal     If the ellipsoid semi axes are stored successful the
              function returns TRUE, otherwise FALSE.

This function is a component of the unlock requiring function group
"user definitions". It is unlocked for unrestricted use together with the
other functions of the group by passing the unlock parameters, acquired
from the software distribution company, trough the function setunlockcode().
Without unlocking only a few function calls for test purposes (shareware
principle) are possible.