Geotagging Overview

Geotagging is the process of adding GPS coordinates to photos, so they can be visualised on a map (such as Google Maps and Google Earth). On line services such as Flicker and Picasa provide this visualisation on their websites. I personally have spent time on holidays touring various cities and taking hundreds of photos of beautiful buildings, only to get home and not know where the photo was taken. Geotagging will solve this problem, and as always, it is quick and easy when you know how.

There are a lot of point of shoot cameras that are coming onto the market that have a built in GPS. These cameras automatically add the GPS coordinates to the photo when it is taken, and photos taken by these cameras are hence automatically geotagged. The exception of course is when there is no GPS signal (ie indoors). But as of writing this web page, there are not too many digital SLR cameras that come with a built in GPS device. And of course there are many digital cameras that people have already purchased that do not have a GPS. This article will describe how to go about Geotagging your photos from your digital SLR or point and shoot camera. The steps you will take are to capture a GPS signal with a third party GPS device, and then combinine the GPS coordinates from the GPS track log to your photos using free software that is available on the internet.

Getting Started

There are 3 things you need to do to get started.

1. Get yourself a GPS device that can create track logs
2. Install software on your PC that will combine the tracklog to your photos
3. Accurately set the time on your camera so the tracklog will match your photos

Once you have done these things, you will be ready to go.

Get yourself a GPS

There are plenty of GPS devices on the market that will do this job. You can go for a traditional GPS such at the Explorist 600 that I have reviewed on this website, or you can purchase a specialised device specific for GPS Logging. The first device I purchased specifically for this purpose was the I-Got-U device. While this does the job, I found that it is not overly accurate, and also a bit slow to use during the geotagging process. I am sure there will be many more of these dedicated devices coming on the market in the near future, so just do a Google Geotagging Search to keep up to speed with what is available.

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Blackberry as a GPS Logger

What I didn't know when I started, was there is some great software available for Blackberry devices that will record a tracklog for you that you can use for geotagging. I have looked at a couple of different tools, but the one I like the best is GPSLogger. This software is free, however you may like to make a donation to the author if you find the software useful. You can download this software directly over the web by browsing to this link with your blackberry browser and then selecting download. It will work straight out of the box.

Once you have installed GPSLogger on your Blackberry, there are some options that you should set up. Set a target email address in the options. This email address will be used to email the track logs directly to yourself from the Blackberry. The software is easy to use. Just start logging and then save your tracklog when you are finished. You then need to browse back to Path Manager from the menu and export the recorded path to either the file system or via email. Both will work, and it depends what is the easiest way for you to get your tracklog onto your PC.

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PC Software to Tag Photos

There is a peice of software available on the web called EXIFTool. This is a fabulous piece of software, however it is not for the faint hearted and certainly not for casual users. What I have found however by doing some research is that there is other free software on the web that use the EXIFTool, but provide an intuitive, easy to use interface to complete the geotagging task. The software I have found to be the best is GEOSetter. I recommend you download and install this software and use it for your geotagging tasks. Like the Blackberry software above, I recommend you make a donation to the author if you find this software useful.

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Accurately set the time on your camera

This is one of the most important steps in the process. If the time on your camera is not very accurate, the geotagging process will be unpredictable. As you may know, GPS satellites use very accurate time stamps and a process called trilateration to find out where you are physically located on the surface of the earth (or in a plane). The point is that GPS satellites have very accurate clocks, so there is no chance that time in your track log will be wrong. You just need to make sure that the time on your camera is equally as accurate.

First accurately set your PC time

The best way I can suggest to set the time on your camera, is to first of all set the time on your PC using an Internet Time Server. If you are using windows XP or later, this is a very simple process. In fact chances are your PC does it automatically. But just to be sure, this is what you need to do.

1. In the bottom right hand corner of your task bar, you will find a clock. Double click on the time, and the Windows date and time properties box will appear.
2. Click on the internet time tab.
3. Select a time server. I use time.windows.com but you can use any other server you like
4. Click update now. You should get a message saying your time has been successfully updated.
5. Check that the Automatically syncronise option is checked.
6. Click OK to close the dialog box

You should also check that you have the correct time zone specificed for your PC.

Then set the time on your camera

Now your PC has the accurate time, double click on the time again to bring up the analogue clock with the second hand (you may need to click the date and time tab to see the clock). Go to the settings in your camera and adjust the time on your camera to be the same as you PC to within one second. You will find that your camera also has a time zone setting, so make sure that is set correctly and the same time zone as your PC (assuming you are not travelling).

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Take your photos and then add the geotags

The last thing to do is take some photos and then add the geotags. What I suggest you do is go outside and start your GPS device. Once the track log is recording, walk up and down your street and take some photos of a few different houses on each side of the street. Make sure you get the house numbers in the photo.

Some GPS devices have a screen that shows the current time from the satellites. This is not to be confused with the time on your device (ie if you have a Blackberry). If your GPS has a time screen, take a photo of your GPS. This will give you a reference photo that shows the time on your GPS. The photo itself will have a Time Taken timestamp. When you get back to your PC, you can compare the time stamp with the image, and determine if there is a difference between the two. The GeoSetter software will allow you to make adjustments for these differences when you complete the geotagging step.

Once you have taken a few photos, stop the GPS and get your track log back onto your PC using what ever method is appropriate for your GPS device. Also copy your photos onto your PC from your camera. I suggest you copy the GPS log file into the same folder as the photos.

Your GPS will record the time in the track log using UTC. The GeoSetter software will automatically sense the time zone on your pc, and adjust the GPS track log to suit. That is one of the benefits of using this software.

Geotag your photos

You should now have all your photos in one folder along with your GPS tracklog. Start GeoSetter and open the folder that contains your photos and the track log. Allow some time for the photos to open and the track log(s) to appear on the map.

If you took a photo of your GPS time in the steps above, find this photo in the list of photos. Note the difference in seconds between the photo image and the time stamp of the photo. Click the 'syncronise the geodata' button (Ctrl-G). You should be able to accept all the defaults in the dialog box. If you have been travelling and you have changed the time zone on your camera, you will need to change the timezone setting in the time adjustment section. You can then specify an additional time adjustment using the feature at the bottom of the dialog box. Adjust the time based on the difference between the photo image time of your GPS and the time stamp on your photo. You can also use this feature to compare the time on your camera with the time on your PC. Make the same adjustment based on the difference.

That's it, you are done. You should now be able to click on the photos in the left hand pane of GeoSetter, and see a map pin on the left showing where the photo was taken. You can then do anything you want with your images, and any software that handles geotagging will react to the photos. You can click the Export to Google Earth button in GeoSetter and this will create a KMZ file that you can view in Goolge Earth. If you use Picasa for managing your photos, you can see the photos with a map attached. When you load your photos onto the web with Picsa or Flicker, the photos will appear on the map where you took the photos.

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