Write a PHP code for NTv2 National Transformation

NTv2 stands for National Transformation version 2, and describes a binairy grid format, used to perform high accuracy datum conversions between coordinates. A single NTv2 file can contain various grids with different accuracies. I need a php code for coordinates to be converted using the most accurate grid available. To get the actual datum shift for a coordinate, the 4 closest known coordinates are retrieved from a grid file, and then interpolated using bi-linear interpolation. The default extension for NTv2 grid files is .GSB (Grid Shift Binary). There is also an ASCII variant of this file, which is using the extension .GSA (Grid Shift ASCII). Please see a prototype here [login to view URL] The web program is a simple php code that does bi-linear interpolation either from a single input entry or batch file processing entry. You need to have an understating of bi-linear interpolation software. You can download a simple interpolation software here to have an idea [login to view URL] I will send the grid file file and other key coordinates to be used.I will also specify the Datums that require the transformation. Transformation is geographic only. I have also attached here a sample C code that will give you more idea of how the functions of interpolation works. If you can modify the module and translate to a php code, the job becomes a lot easier. Please find the attached C code. You will be required to: [login to view URL] the forms where data will be entered in single and batch processing. Please see [login to view URL] 2. Design the interpolation php code and any other CGI script 3. Upload the php code to any domain where I can test run it. This web application requires no database or sql or anything login interface.