EXIF marks the spot: a guide to geotagging pictures

Geotagging pictures allows you to more easily search your photos based on where you’ve been. In addition to online tools such as flickr and Picasa, desktop apps like iPhoto will take advantage of geotags. (Facebook is a notable exception; it currently doesn’t use geotags.)

You can also create visualizations of your travels like this:

A map of my favorite pictures on flickr.
A map of my favorite pictures on flickr.

Digital photo files contain EXIF headers that store information about the picture. The information that most people are familiar with is the time and date. Each picture can contain hundreds of fields that include minutiae about the cameras settings, including aperture, shutter speed, program modes, etc. Geotags store latitude, longitude and elevation. You can see a sample of EXIF data on flickr. (The geotags are toward the bottom of the page.)

Unfortunately, the actual process of geotagging is still cumbersome. It’s a lot easier than it used to be, but shy of what it should be to make it mainstream.

Here are a few options for geotagging your pictures:

A dedicated GPS that can record GPX tracklogs

A hiking GPS can record your every move. As you walk, hike or run, the GPS unit logs your current location. (As frequently as once per second.) These are recorded on a memory card in a .gpx file. When you return to your computer, you can pull that file and then the photos from your camera’s memory card. Specialized software (such as GeoSetter) then synchronizes the timestamps of the photos with the data from the GPX tracklog and writes the location information into the file.

Don’t worry if the timestamps are off. GeoSetter offers numerous ways to adjust the timestamps so that the time recorded in your pictures lines up with the time in the location data. (To make this easier, I recommend taking a picture of the time display on your GPS at the beginning and end of your trip.)

I’ve used a Garmin eTrex Vista Cx. Any GPS that can write GPX files to a memory card will do the trick.

Advantages: Works really well when outdoors. Precise location, due to GPS accuracy and frequency of updates. The GPS also provides valuable information when you are hiking.

Disadvantages: Additional cost for the GPS unit. Because you aren’t looking at the GPS unit when taking pictures, you may miss errors such as being out of coverage, dead batteries or a full memory card. It’s another thing to carry. Applying the coordinates is a multi-step process. If you go to a distant location, the GPS can take up to 20 minutes to get an initial fix. It may be difficult to get a fix in densely packed urban areas. (In any case, when you head indoors, you’ll have to rely on the last reading.)

Using an Android or iPhone app to record GPX tracklogs

This works pretty much the same as having a dedicated GPS, except that it relies on your cell phone to track your position. The biggest downside is that it will chew through your phone’s battery very quickly. I use Motion-X GPS on the iPhone and My Tracks on Android.

Advantages: Works really well whether indoors or outdoors. Precise location, due to GPS accuracy and frequency of updates. The GPS also provides valuable information when you are hiking. No additional cost. Because the phone can approximate your location in other ways, the time to a GPS fix is much faster.

Disadvantages: Because you aren’t looking at the phone when when taking pictures, you may miss errors such as being out of coverage, dead batteries or a full memory card. Multi-step process. The GPS app will chew through your phone’s battery very quickly.

A geotagging digital camera

Specialized digital cameras can automatically geotag photos. I have a Panasonic DMC-ZS7. It will automatically write the current location into the data file when you take a picture. No lining up separate files or manually geotagging pictures. The Panasonic has a built-in landmarks database. Standing in front of the Statue of Liberty? The screen will show “Statue of Liberty”. In playback mode, the camera will let you browse pictures by location.

Incredible? Yes. Too good to be true? Sadly, also yes. When it works, it’s like magic. When it doesn’t… it just adds incorrect data to the picture.

There are two big problems with Panasonic’s implementation: it takes way too long to get a fix and it doesn’t update when the camera takes a picture. Often when I’ve arrived in a new location, the camera is still showing the old location hours later. The instructions claim that the camera updates location even when it’s off; I haven’t found that to be true.  Even at its best, the location only updates every five minutes. Undoubtedly, the camera’s designers faced challenges trading off the accuracy of the GPS location against battery life. The balance they struck made the GPS feature largely useless.

Advantages: Simplicity. Works OK when outdoors. Because the location is shown on screen, you can determine whether it’s correct and that there are no other issues.

Disadvantages: Location information is often wrong. Very long time to first fix. The GPS uses the camera’s battery. (I didn’t find this to be a huge issue, but you may want to carry a spare battery.) Despite the fact that the camera knows the nearby landmark, it doesn’t write it into the EXIF data in a way flickr and other tools can read. Poor indoor coverage. Additional cost when compared with cameras without GPS capability.

Eye-Fi memory card

Eye-Fi sells a line of memory cards that will geotag locations. The primary purpose of the cards is to automatically upload your pictures to the Internet. But they’ve expanded the capabilities to also geotag the pictures.

Here is how Eye-Fi works: when you take pictures, nearby WiFi networks are recorded. During the upload process, those network locations are used to compute a location using Skyhook’s database of WiFi locations.

Advantages: Simplicity. Works well indoors, especially dense urban areas in the United States.

Disadvantages: The Eye-Fi cards cost substantially more than comparable SD cards (sometimes 10x). It won’t work when you’re in an area without WiFi signals, which rules out EyeFi for geotagging many hikes. The Eye-Fi card’s WiFi capabilities will drain your camera’s battery faster. The locations are added after the fact, so you won’t be aware of any problems when shooting. Geotagging relies on Skyhook’s database of WiFi locations, which can be sparse in foreign locations.

Manually geotagging pictures

For a while, this was the only option. Take pictures that you’ve uploaded and drag them onto a map. This can be as accurate or as inaccurate as you want it to be.

You can take all of your pictures of Venice and drop them onto the city of Venice. Or you can zoom in to just the right piazza and repeat the process for each picture. I once looked into the background of an old picture, found a business name there and did a Google Maps search to put it in the right place. It can be tedious, fun or both. Flickr and Picasa both support manual geotagging.

Advantages: Doesn’t cost anything other than your time. You have precise control over where each picture is placed.

Disadvantages: It can be extremely tedious. Lining up pictures taken outdoors (such as while skiing or hiking) can be difficult.

Using your cellphone’s camera

This is likely the way that most people get into geotagging. If you have an Android phone or iPhone, your camera can do all of the work for you. Based on the same services used for maps and other location services, the phone will write the picture’s coordinates straight into the file. You can also verify that the location is correct by launching a maps app before taking the picture.

It’s so easy that many privacy advocates worry that people are unintentionally revealing their locations when uploading pictures.

Advantages: Simplicity. Can verify information on screen. No additional cost.

Disadvantages: As good as they are, the cameras on phones aren’t as good as regular cameras. This is especially true for pictures needing zoom or taken in low light.

The best solution would be if the camera manufacturers would work with the phone manufacturers to just read the current GPS data when the shutter is pressed. I’d bet that the iPhone gets a microSD card slot before that happens.

Facebook Places is at the beginning of a long road

Facebook Places on the iPhone
Facebook Places on the iPhone

Facebook’s much awaited Places product finally launched this week. It’s the first step toward bringing friend finding to the masses.

People have been using Facebook to do this for years; posting their location in freeform status updates that their friends can read and comment on. (e.g. “heading to Cambridge for dinner.”) By turning that freeform text into structured location data, Facebook can make that data more useful.

From an iPhone or HTML5-capable mobile device, you can check in to a place, such as a restaurant, bar, movie theater, airport. You can also leave a message with the check in. The check in is posted to your wall and may appears in friends’ news feeds. On the mobile side, you can see a list of your friends and where they’ve checked in. Clicking on a place will show you details of the place, including a map and who has checked in.

The initial release is fairly simple. In fact, it’s not that much more useful than the freeform status updates.

Facebook is entering a very crowded space with competitors such as foursquare, Gowalla, Loopt, Google Latitude, Whrrl and Twitter. Many of those products are much more robust. Facebook’s key advantage is the size of its social graph: within the past 24 hours, 18 of my friends have checked in.

There are many opportunities for improvement to Facebook Places:

  • Basic UI. Check ins are sorted by time, not distance. A friend checking in 2,000 miles away 2 minutes ago is less relevant than someone checking in 2 miles away 5 minutes ago. This problem is exacerbated by the fact that the city isn’t shown. Considering that many people use Facebook to keep track of friends all around the world, this is a significant issue. Foursquare has a separate bucket of “Friends in other cities.” Update: Facebook now has a separate grouping of nearby friends.
  • Map view. Often, visualizing your friends on a map is much easier than scanning a list. Foursquare already offers this.
  • Visiting friends. Out of town friends who are in town aren’t indicated. One of the big potential values of social friend finding is discovering when friends are in town. If a friend from far away is visiting, I’m more inclined to want to get together than someone who lives in town.
  • Pictures. There is no way to associate a picture with a check in. Given the difficulty in typing on mobile devices, often a picture gives a lot more information. These pictures could also be used to build a much more robust Place page.
  • Pushing location. Sending people your location via SMS is tedious. You have to address the message, type out where you are. If they don’t know where it is, they have to pull up a map or text you back for directions. With Places, it would be easy to push a notification to friends with where you are, complete with map. This could be sent as a push notification on iPhones or as an SMS with a URL for other phones.

As with most Facebook product launches, questions of privacy come up. In general, I think Facebook has done a good job with the default privacy settings on Places. You must explicitly check in; there is no background tracking.

Only your friends can see where you’ve checked in. Unfortunately, my social graph on Facebook wasn’t designed with location in mind. When I decided whether or not to accept friend requests on foursquare, I used a tighter filter than on Facebook. Now, I’ll have to go back through Facebook friends and create a list of who should have access to location. (See Post technology columnist Rob Pegoraro’s piece on how he classifies his friends.) Yes, old high school friends have been known to burgle homes based on Facebook updates. If that worries you, watch Rob’s video on how to adjust your privacy settings for Places.

The one big complaint I have with the privacy defaults is that your friends can check you into a location without your permission.

See also:

Checking in with foursquare at SFO

SFO is a hotbed of foursquare activity
SFO is a hotbed of foursquare activity. Creative Commons image by Håkan Dahlström.

With the increasing use of mobile applications such as Yelp and foursquare, it’s becoming possible to pull ideas from thin air. Users of these apps can leave tips for others to find that are linked to a specific location.

In most places there aren’t enough tips yet to make filtering an issue. San Francisco International Airport, with more than 57,000 checkins on foursquare, is an exception. It offers a glimpse of what we can expect as these services become more popular. The airport is the perfect petri dish for tips: it serves a technically savvy audience and people often find themselves there with plenty of time on their hands.

The SFO tips page contains dozens of notes including places to eat, complaints, ground transportation, wifi and power availability. Mixed in to all of this are ads, other spam and random observations. Some examples:

have a corned beef sandwich at max’s if you’re flying southwest. the best! well, really good

When you enter short term parking do it as far to the right as you can (lvl 2) & then immediately head to lvl 1. There is always parking next to gate and that is the lvl that connects to the terminal

Free wifi at the Continental lounge in Terminal 1- be warned, it’s located outside Security

Smoking hot brunette woman at gate 20. Stop by and smile at her. She is so lovely!

Bart to Millbrae gets you within 1 block of an in n out burger. Great for 3+ hour layover!

Heading to wine country? Take a moment to stop by St. Supery in the heart of Napa on Hwy 29. Mention this to get a 2 for 1 tasting.

Sorting through the volume of tips can be overwhelming. As the volume increases, we’ll need ways to filter them. Among the ways to filter:

  • Timeliness. Some of the tips, such as wifi at the Continental lounge, are evergreen. Others, like the smoking hot brunette are very timely. Tipsters should be able to flag their tips to self destruct. As I wrote earlier, being able to identify tips by timeliness would allow for new applications, such as sharing rides. (“Anyone want to split a cab to Moscone?”)
  • Social network. Among the tips were tips from people I follow on Twitter, including Danny Sullivan and Adam Lasnik. Being able to surface these would increase relevance.
  • Ads vs. not ads. Sometimes people want ads, especially if it can save them money.
  • Keyword search.

Places like airports are especially complex because they’re really collections of places, sometimes with other groupings and physical restrictions. Being able to filter tips by terminal would also be useful. But then maybe that’s best left to GateGuru.

Now we're going Places

I’ve been writing about Twitter and location since my first post about Twitter in 2007. This week, Twitter launched Places, which allows users to add their location to a tweet.

Here’s a screenshot from 2007:

Twitter location 2007
Embedding location in a tweet the hard way in 2007

and today:

Embedding location in a tweet in 2010

In 2007, I used a third-party application from Where to include my location. Clicking on that link would take you to a map on Where’s site showing the address. (The link in the original post no longer works.)

With the launch of Twitter Places, the search is done within the Web browser (and soon in Twitter’s mobile applications). You can select where you are from a list of nearby places. Clicking on the place name brings up the map above and the option to view tweets about that place.

Although the difference between the two may seem subtle, they are significant:

  • Because the place is metadata, it doesn’t count toward the 140 character limit.
  • Place names are human readable, unlike addresses and latitude/longitude. Knowing the name of a place makes it much easier to find than just a street address, especially in dense metropolitan areas.
  • Places are unique to a specific venue. Doing a pure location-based search would return tweets from surrounding businesses or businesses that have since disappeared.
  • Integration in to the main Twitter experience means broad exposure and eventual standardization of place identifiers. That has been a longstanding challenge in the local space.

Twitter’s geo APIs have been available for several months and third parties like bing have created interesting applications like Twitter Maps. With the availability of places across the Twitter platform, we can expect to see more interesting applications including both real-time applications (ride sharing and ticket exchanges) and historical (restaurant reviews, past events).

Once Twitter allows owners to claim their Place and associate it with a Twitter account, we could see official tweets of announcements and offers incorporated into a Place’s search results.

When pictures are tagged to a Place (instead of a lat/long), we’ll have the ability to visually browse a venue in Twitter.

Geo-enabled Twitter comes alive on Twitter Maps

Bing's Twitter Maps show you what's going on
Bing's Twitter Maps show you what's going on

I’ve been playing with Bing’s Twitter Maps lately and it’s one of the better implementations of Twitter’s geo APIs that were introduced last fall. It shows tweets and foursquare checkins within the last 7 days plotted on the map. Google Maps recently introduced a similar feature, but it seems to only show items that are fed through Google Buzz (including tweets that people have configured to send to Buzz).

Some future applications of geo-enabled Tweets:

  • Events. For last-minute party goers, a real time view of what’s going on around town, complete with pictures and real-time reactions.
  • Ticket scalping. Rather than walk around for blocks talking to scalpers about what they have, glance at a list of tickets posted. The information transparency would result in a higher price to sellers and a lower price to buyers than what scalpers typically offer. (In my experience at baseball games, scalpers usually ask at least 3x what they paid.)
  • Finding a place to go. When in new cities, it’s often hard to figure out where to go — what are the lively neighborhoods at night. By looking at a map of recent tweets, you could quickly discover where people are still awake.
  • Read reviews from friends. Geo-enabled tweets filtered by those you follow would provide socially relevant recommendations.
  • Offers from local businesses. These could be persistent or distressed inventory. Slow night? Tweet an offer to draw in customers.
  • News. Twitter has long been used for user-generated breaking news. With geo-enabled tweets, breaking news could be aggregated by location in addition to hashtags. The biggest stories could be identified by an increase of tweets from a location (versus normal) and retweet frequency. News from media outlets could also be plotted.
  • Construction and accident information. Avoid bottlenecks by seeing tweets from fellow drivers, DOTs and news sites.
  • Trip sharing. Find others at the airport headed your way, cutting costs and reducing pollution.

And, of course, there’s friend finding, which is the most talked about use of geo-enabled tweets.

So far, the percentage of tweets I see with geo information is tiny (>1% of those I follow). But as more and more geotagged data is put into Twitter, the key will be applications providing the right tools to filter all of that data. At a minimum, we’ll need the ability to filter by time of tweet, people we’re following, hashtag and application (e.g. foursquare).

Unfortunately, bing’s Twitter Maps doesn’t seem to be available where real-time information would be most useful — on mobile devices.

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