Where was that picture taken?

Anytime you travel, pictures accumulate quickly. A few weeks after they are taken, you still have a good idea where each one came from. However, after a few months some of the place names start to fade, and the approximate location gets a bit hazy too. However, if you bring your GPS along, then determining where those pictures were taken becomes easy.

Geocoding the pictures

Geocoding is storing location coordinates with the picture.

The Window’s program GPicSync helps to determine where pictures were taken. The pictures must be in JPG format, and have the proper date and time recorded in its EXIF data. Since most digital cameras store their images as JPG with EXIF data, this should not be a problem. GPicSync uses the date and time information from the pictures, along with a set of GPX (GPS Exchange Format) track files from the GPS to assign coordinates to the picture. From the time stamp of the picture, it identifies which GPS track coordinate was the closest to where the picture was actually taken using the time and date information recorded in the GPX file.

Even if the cameras clock was not properly set, knowing what it thinks the time is versus what the GPS thinks the time is can be used to calculate a correction offset.

GPicSync is a free program available from sourceforge.net.

GPicSync Screenshot

The ‘Pictures folder’ button allows selection of a single directory. The ‘GPS file’ button allows for selection of multiple GPX files or NMEA files. Make sure ‘add geonames and geotagged’ is checked to allow updating the picture’s EXIF data with the GPS coordinates. Since the GPS records time in UTC, and the camera in local time, you will need to provide the UTC offset where the pictures were taken. For the difference to nearest track point value, 300 is sufficient for most cases. However, if you go into a building and take pictures for a while, then bumping this up will allow for matching. This is to account for GPS not working well inside. For a recent trip to an aquarium, a difference to nearest track point value of 5000 seconds worked well. This large value was because we were inside for over an hour.

Press ‘Synchronise !’ and GPicSync will automatically attempt to match each photo with a point in your GPS track data. When it finishes, clicking on ‘View in Google Earth’ will push the track data, and associated pictures to the Google Earth application for viewing. However, I find it easier to examine the images and locations via Google Maps, which is where GeoSetter comes in.

Viewing images by location

GeoSetter is a free Window’s program for viewing geocoded images within Google Maps. It also provides the ability to match pictures to their GPS coordinates, but the interface is very error prone, and most of my Osaka pictures ended up in Berlin the first time I tried it. So for now I prefer GPicSync for updating the picture’s coordinates, and GeoSetter to put the images into their geographical context.

Download GeoSetter

GeoSetter Screenshot

GeoSetter’s interface is fairly simple. The thumbnails are what you find in Window’s Explorer thumbnail view, and performing a right click on an image gives exactly the same set of choices that Window’s Explorer provides. However, this is not very useful for an application’s context menu. The most reliable way I have found to get an image to appear is to select the image(s) of interest, and then press Ctrl+Z. Ctrl+Z is the same function provided by the magnifying glass with a single head in it to the right of the thumbnails. Multiple images can be selected from the thumbnail view by holding the Control (Ctrl) key while selecting each image. The map display uses Google Map’s interface.

Wrap Up

There currently are no cheap cameras which provide GPS capabilities. There are a few standalone GPS units such as Sony’s GPS receiver targeted towards cameras, but the reviews are not favorable. If you are planning your trip with a GPS in mind, then using that GPS to handle your photos is your best solution. Just make sure that you set your camera’s clock to match that of the GPS. After that, leave it to GPicSync to use your GPS’s tracks to set each picture’s location.

Once coordinates have been added to a picture, other tools can take advantage of this. Google’s Picasa can view geocoded images with Google Earth. Flickr and Panoramio are community sites which take advantage of the geographic data. Flickr also has an interface to help you locate where your picture was taken which may be sufficient for a small number of pictures.

Enjoy your trip, take lots of pictures, and when you get back it will be easy to record where those pictures were taken.

What are your recommendations for dealing with trip pictures?

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One Comment on “Where was that picture taken?”

  1. Stephen Says:

    Eye-Fi has extended their Wi-Fi SD memory offering to include geocoding capabilities using information about local Wi-Fi Hot Spots to automatically geocode images. Eye-Fi Explore