Prototype and description of the function setntvbinaryfile() (Function of the unlock requiring group "NTv2 Transformations")
 setntvbinaryfile() Initializes a NTv2 grid data binary file for Reference System Transition. Prototype of the DLL function in C++ syntax (attend lower case!): extern "C" __declspec(dllimport) unsigned long __stdcall setntvbinaryfile( char *pszFileBinary); Prototype of the DLL function in Visual Objects syntax: _DLL function setntvbinaryfile(; pszFileBinary as psz); // 4 Byte, char* as logic pascal:geodll32.setntvbinaryfile // 4 Byte The function tests and initializes a NTv2 grid data binary file containing grid data for NTv2 Reference System Transitions. The grid data are used, when one of the functions coordtrans???() has set the Reference System flags for a NTv2 Reference System Transition. The memory space required for NTv2 Reference System Transitions is allocated regardless of the actual execution of NTv2 Reference System Transitions. The testing of the file content is made directly with the function call and any error messages are directly initialized by the function setntvbinaryfile(). For geodetic calculations with NTv2 grid files GeoDLL can make aware of the paths of the files with further functions: The function setntvbinautofile() can be used to store the NTv2 file path only in a waiting position. Testing and the allocation of memory space takes place primary with the first NTv2 Reference System Transition. With the function setntvbinautodir() an automatically selection and initializtion of the required NTv2 file can be realized. For this purpose, the required NTv2 files must be stored in a common directory with up to three subdirectories. When changing to a NTv2-based Reference System, the required NTv2 file is searched there. If the file is present in the common directory, it is initialized automatically. You can download the NTv2 files supported by GeoDLL directly from the KilletSoft website http://www.killetsoft.de/p_gdln_e.htm#download or use the download links to the original sources there. On that Internet site you also find a detailed description of the NTv2 standard. The file name may contain a drive letter, a directory path and a file name extension. The file name extension for NTv2 binary files is by standard "gsb". Example: "c:\calculations\ntv2_files\beta2007.gsb". Attention, in C syntax double backslashes must be used! With the functions getntvbinaryfile() and setntvbinaryfile() an automatically selection and initializtion of the required NTv2 file can be realized. For this purpose, the required NTv2 files must be stored in a common directory. When changing to a NTv2-based Reference System, the name of the required NTv2 file is determined by the function getntvbinaryfile(). If the file is present in the common directory, it is initialized there with the function setntvbinaryfile(). The parameters are passed and/or returned as follows: pszFileBinary File name of a NTv2 binary file. The file name may contain a drive letter, a directory path and a file name extension. 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 Transformations". 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. It should be noted that in addition the function group "Coordinate Transformations" must be unlocked.