searching for values in a text file

hi i have generated 2 arrays for latitude and longitude, now i want to search through a text file and when a entry with a latitude AND longitude that matches those in my list i would like the program to return those rows. the text file has latitude in column 1, longitude in column 2 and shear anomaly in column 3,i am after the shear anomaly value for the entries with lat and long matching those in the arrays i have made

[Azzi Abdelmalek]

Post a sample of your data in your txt file

[Walter Roberson]

Also, are the matches going to be exact or should there be a match to the "closest" element ?

[Muhammad Ahsan Khan]

Why is there no answer to this issue? I have the same problem. Any help?