Prototype and description of the function getntvminmaxshift()

(Function of the unlock requiring group "NTv2 Tools")

 

getntvminmaxshift()
Determination of the min / max shift values of one or all NTv2 subgrids.

Prototype of the DLL function in C++ syntax (attend lower case!):
__declspec(dllimport) unsigned long __stdcall getntvminmaxshift(
     char *pszFileNtv,
     unsigned long lAscii,
     unsigned short nGridNo,
     double *fMinShift,
     double *fMaxShift)

Prototype of the DLL function in Visual Objects syntax:
_DLL function getntvminmaxshift;
     (pszFileNtv as psz,;                  // 4 Byte, char*
     lAscii as logic,;                     // 4 Byte
     nGridNo as word,;                     // 2 Byte
     fMinShift ref real8,;                 // 4 Byte
     fMaxShift ref real8);                 // 4 Byte
as logic pascal:geodll32.getntvminmaxshift


The parameters are passed and/or returned as follows:
pszFileNtv  File name of the ASCII or binary formatted NTv2 file from which
            the minimum and maximum shift values are to be determined. The
            file name may contain a drive letter, a directory path and a
            file name extension.

lAscii      TRUE: The NTv2 file is ASCII formatted.
            FALSE: The NTv2 file is binary formatted.

nGridNo     n: Number of the subgrid from which the the minimum and maximum
               shift values are to be determined.
            0: The minimum and maximum shift values of all subgrids
               contained in the NTv2 file are added together.

fMinShift   Smallest (minimum) shift value of one or all NTv2 grids.
(ref)       The value is the absolute value of the smallest determined shift
            value in geodetic seconds, which is calculated from the shifts in
            latitude and longitude according to Pytagoras.

fMaxShift   Largest (maximum) shift value of one or all NTv2 grids.
(ref)       The value is the absolute value of the largest determined shift
            value in geodetic seconds, which is calculated from the shifts in
            latitude and longitude according to Pytagoras.

returnVal   In case of an error the function returns FALSE, otherwise TRUE.


Unlocking:
This function is a component of the unlock requiring function group "NTv2
tools". 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 no
calls for test purposes (shareware principle) are possible with this function.