The main thing I want to know is how to check/compare if the lat and long received from the GPS through GSM modem are located before, after or at point X or Y.

Thanks, Yes I agree with you that I'm missing some other possibilities. It become more complex, the other possibilities is when either long is less or greater and lat is equal and opposite.

I'm developing a system which I want to locate different places. Have the database which contain some Latitude and longitude and want to compare with the one received from the GPS through GSM modem which are string. Example Latitude 3.23909S, Longitude 36.47961E. Assume I have in the database Latitude 3.24907S, Longitude 37.57899E as Location X and Latitude 2.98765S, Longitude 35.46769E as location Y. How can I compare and say that the string received...