239726 Database Functions

i need someone is VERY Familar with PHP and mysql. to create me a few functions to do the following: 1. i want to provide a set of latitude and logitude. the function have to search in the database (presort by SQL Statement required) for "nearest positions" and output the distance and to it ... 2. a function can find in 2 tables "nearest positions" i have a table with points of interests .. and another table with trackig data ... (both have lat/long informations) the output shall show the time spend in a given radius near by the set in the first table. 3. export an array with speed-data based on tracking informations. as example 1440 points for a full day ... where not existing data have to be filled with NULL .. or something semilar. i can provide read-access to the production DB for testing. script must be in PHP4 and not load intensive as there are over 4million Position informations stored already. the presort of the position output via SQL can be Straight forward (no need to calculate "exactly") example: [login to view URL] or: [login to view URL]