Read GPS data from Photographs using PHP

Modern cameras equipped with GPS receivers add the GPS coordinates to every photographs it takes. Using this data, the exact location where the photograph was taken can be determined. This information can be very useful when archiving or organizing the photographs. The GPS data will be embedded in the photo along with the EXIF header. In this post I will show you how to extract this information and convert it to some meaningful data using PHP.

Convert Latitude and Longitude From Degrees Minutes Seconds format to Decimal

Latitudes and Longitudes are mostly represented in the DMS (Degrees Minutes Seconds) format but for many applications, you need the values in decimal format. The decimal values can be easily stored and retrieved from database compared to DMS format. For creating maps using applications like Google Maps, it would be quite simple if you have those values in decimal format. In this post, the steps involved in this conversion are described.

Understanding Latitudes and Longitudes

You might have come across these terms in may be your 8th grade science class or sometimes even earlier. If you are looking for some short refreshment course then go ahead.
Any location on Earth can be described by two numbers, its latitude and its longitude. These are two angles, measured in degrees, minutes and seconds. These are denoted by the symbols ( °,   ',   "  ) e.g. 33° 21' 16" means an angle of 33 degrees, 21 minutes and 16 seconds. A degree contains 60 minutes of arc and a minute contains 60 seconds of arc. You may omit the words "of arc" where the context makes it absolutely clear that these are not units of time. Now lets see how these values are measured.

Maximum execution time exceeded - Error in PHP

You might have come across a Fatal error stating Maximum execution time of 30 seconds exceeded when running time consuming PHP scripts. Well, PHP sets its default maximum execution time for a script to 30 seconds so that the server is not overloaded running long scripts. But there are times when you need to run some time consuming scripts that does some database maintenance or processing large amounts of data. In such cases you are likely to exceed the 30 seconds time limit. PHP has a built in function set_time_limit which can be used to change the maximum execution time.