Photo GPS Extract

Introduction

Most digital cameras produce digital images in the JPEG format (Joint Photographic Experts Group). These images are stored as files with the .JPG extension. In many cases the .JPG contains more information than just the image data. One of these extra informations can be the GPS data, with other words: The exact geographic location where the image was taken. My Photo GPS Extract software can read the GPS data from any .JPG file, and show it on a Google map. You can see a preview of the program on YouTube.

How can a picture have a location?

By default, a picture doesn't contain GPS data. You need to have a GPS - enabled camera. This is a camera with an integrated GPS module. Each time you make a photo, the geographic location is added to the photo.

Only a small amount of cameras have a build-in GPS module. There are a few solutions to overcome this problem:

In some cases you can buy an add-on GPS receiver for your camera. It is a little piece of hardware you can connect to your camera with a cable. Of course your camera must support such GPS receiver. Very few does.
Another solution is to add the GPS data to the pictures by hand. You can use programs like Google Picasa for this. In short: you can assign a GPS location to any photo by selecting a location in Google Earth.
The tird option is to carry a portable GPS with logging capabilities while taking pictures. Later you can read the logged route from your GPS, and use a third-party software to merge this information into your photos. This is my preferred way to geotag photos, and I will explain this in detail later on.

Merging GPS data into photos

As I just explained it is my preferred way to Geotag my photos by using an external GPS device. I have bought myself the Garmin Oregon 450t for this reason. It is a portable GPS unit, powered by 2 AA batteries. This unit has many options to save the tracks you have walked. The tracks are stored as files with the .GPX extension (GPS eXchange Format). My tracks usually have an logging interval of 10 seconds. This means the GPS location is recorded every 10 seconds.

You can download the track logs by connecting the GPS device to your computer. Now you have a track logfile on your computer, you can start merging the GPS information into your pictures. But how can you do that? With another software tool! I use the commercial RoboGEO software [External] to do this. These are the neccesary steps to follow:

Open the RoboGEO software.
Import your pictures into RoboGEO (File > Get Images > Entire Folder).
Import your track log into RoboGEO (File > Get Locations > Track Log > Import Track Log File)
Now RoboGEO will try to find the GPS location for each picture.
When RoboGEO is done you have to write the GPS location into the .JPG files (File > Process > Write Exif Headers)

You are done! Now all of your pictures will contain the GPS location.

You might be wondering how RoboGEO can link a picture with a location. First of all you should be aware that each photo contains the date & time of its creation. RoboGEO will read this information from all of your selected .JPG files. Then it will search the .GPX track log to see where you were at each of these times.

Function of the Photo GPS Extractor Tool

Having the GPS coordinates inside your pictures is a nice thing. But it is useless without some software that will show the location on a map. This is why I've created the 'Photo GPS Extractor' tool.

With this program you can right-click a .JPG file, and click the option 'Photo GPS Extractor'. Then the following screen will be shown:

Screenshot of the Photographic GPS Extracter tool Photo GPS Extractor shows a map with a marker on the location where the selected picture was taken. You can use functions like ZOOM-IN and ZOOM-OUT, PANNING (moving the map by dragging it).

Of course, you can also start Photo GPS Extractor in the normal way, and use the command "File/Open Image". The file will be opened, and the Exif is searched for any GPS coordinates. If the GPS coordinates (or the Exif it selves) are not available, a warning dialog-box wills pop-up.

Photo GPS Extractor offers some extra options, like the default Map-type you want to see. You can choose between MAP, SATELLITE and HYBRID.

- MAP: This card only shows the roads. (This card starts very quickly.

- SATELLITE: This is a card that shows real photos, taken from a satellite. You can easily recognize houses and even cars. This card is a little bit slower to load, and there is no satellite-image available for all places on earth.

- HYBRID: This is a combination of the MAP and the SATELLITE.

Principle of the program

Actually, this program is just a Web Browser application. The maps are provided by Google-Maps. My program reads the GPS data from a file and opens it in a integrated web browser. Photo GPS Extractor requires an active Internet connection.

Download

The program was originally written in Visual Basic 5.0. Later it was rewritten for .NET. There is no added functionality between the two versions.

Developed in:	Visual Basic 5.0 Professional
Download type:	Zipped Setup
License:	Freeware
Size:	7.2 MB
Source code:	not available
MD5 Checksum:	304e06952cd60ef0f64d851678f2b6c9

Developed in:	Visual Basic 2008 .NET Express
Download type:	Zipped Setup
License:	Freeware
Size:	252 kB
Source code:	not available
MD5 Checksum:	9bab171ec688b10668f3c27b3a97503b

Sample photo's

The table below is showing some sample photos I took during my holydays. Each of the images is geotagged so you can open them with PGE to see where it was taken (Belgium,France,England,Netherlands). You can just click any of the images to download it to your computer. In the case your browser doesn't support direct downloading of the .JPG files you can always right-click the image. The browser will show a pop-up window that should have a download/save option.