PHP Script to Convert Lat/Long to Microsoft Terraserver USA grid

Need a PHP function to convert a decimal latitude/longitude with scaling factor to a 3x3 tile grid conforming to Microsoft Terraserver USA linking specifications. Terraserver USA linking specifications are here... [login to view URL] Basically, the function is fed three arguments: decimal latitude, decimal longitude, and scaling factor (S value between 8-19 in the linking specs). It returns an array of 9 coordinates with X, Y, and Z values (per the linking specs). These coordinates can be used to create a 3x3 tile grid with the original latitude/longitude coordinate in the center tile of the grid. Well-commented code is a must. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform It should run on PHP 4.x and be in plain code that can be read in any text editor.