Location data - Introduction to Social Media Investigation: A Hands-on Approach, 1st Edition (2015)

Introduction to Social Media Investigation: A Hands-on Approach, 1st Edition (2015)

Chapter 6. Location data

Abstract

The use of the Internet, and social media in particular, has increasingly moved from desktop computers to mobile devices. Consequently, everything a person does on a mobile device, including his or her activities on social media and social networks, can be associated with a precise location. Social media companies have taken advantage of this. Most offer users the ability to add a location to their status updates. This location information can be a valuable tool for investigation. This chapter shows how location information is connected to posts, how to connect it, and what you can do with it once you collect it.

Keywords

Social media

Social networks

Location

GPS

Geotagging

Geolocation

The use of the internet, and social media in particular, has increasingly moved from desktop computers to mobile devices. In 2013, a study by Adobe found that 71% of people use their mobile device to access social media.1 But unlike desktop computers, mobile devices (such as smartphones) have nearly constant access to a person's location. (GPS is the best known method, but several others exist as well.) Consequently, everything people do on a mobile device, including their activities on social media, can be associated with a precise location.

Social media companies have taken advantage of this. Most offer users the ability to add a location to their status updates.

But why include location with updates? There are many reasons. In some cases, it can encourage face-to-face interaction. For example, on some platforms (like Foursquare), if a user indicates that he is at a particular place, he is automatically notified if any of his social media friends are there, too. Users may want to label their photos' locations to remember where they were taken.

Marketers are also interested. Some businesses offer discounts or other perks to people who post that they are there, since the posts serve as a type of advertising or publicity. They may also look for people who are nearby. An ice cream shop may offer a discount to someone who has posted from a nearby store, hoping to entice him to purchase a sundae.

This location information can be a valuable tool for investigation. This chapter shows how location information is connected to posts, how to find it, and what you can do with it once you collect it.

The Lexicon of Locations

Before delving into finding and using location data from social media, it's helpful to understand the associated terms and symbols used.

Most platforms have adopted a relatively standard location icon, based on location markers typically used in mapping programs:

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On most platforms, moving the mouse over this icon or selecting it will reveal location information. Sometimes, this presents the option to add a location.

For example, on Facebook, users can add a location to a post, even if they are posting from their home computer that does not have a GPS location. The status update box has this location icon, and clicking on it adds a field prompting users to enter their location with the text “Where are you?” (Figure 6.1).

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FIGURE 6.1 The Facebook status update box. The location icon at the bottom left has been clicked, bringing up the small text area that says “Where are you?” Users can enter a location, like a city or a restaurant name, in that box.

There's also a common vocabulary associated with adding location to posts. Geotagging refers to the process of adding a location (or “geolocation”) to a post, photo, or status update. This is typically determined via GPS coordinates, indicating a precise location of the post. This is easy on mobile devices, which know the user's precise location. For status updates with a place-name or a street address, geolocation is what maps that name or address to a pair of latitude-longitude coordinates.

Another way people share their location is through a check-in. Unlike geotagging, which adds a location to a post, a check-in usually involves the user explicitly indicating that they are at a specific location. For example, Figure 6.2 shows our example user Malcom having checked in at Reagan Washington National Airport. The name of the location is a link in Malcom's status update, and the airport's location (Arlington, VA) is listed at the bottom of the update.

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FIGURE 6.2 A check-in at Reagan Washington National Airport.

Collecting Location Information

When searching for location information about an individual under investigation, there are two major categories of data: the individual's own posts and automatically encoded sources.

Future chapters on specific social media websites explain how to find location data on each site. In the meantime, here are general guidelines for finding this information on any site.

User-Provided Location Data

Look for the location icon. On Twitter, for example, posts will have the location icon at the bottom of the post. This is shown in Figure 6.3.

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FIGURE 6.3 Note the location icon after the date in the bottom row of text. The location is listed after that, including a link to the specific place.

On Twitter, location names are usually shown, but these are geocoded. Clicking on the name of the place reveals a map with the GPS coordinates shown.

The place-name in Figure 6.3 is “Jaleo-Bethesda.” If we were to click on that link, the following map would appear (Figure 6.4):

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FIGURE 6.4 The map with the GPS coordinates of the location shown in Figure 6.3. Note the coordinates at the top of the window, along with the location on the map (shown with a pin).

Many sites follow this same pattern: using a location icon to indicate when a user has included a location in a post and linking the location's name to its GPS coordinates.

Check-ins also have locations. These may be addresses, place-names, or GPS coordinates. Facebook's check-in feature, shown in Figure 6.2, features both a place-name (Reagan Washington National Airport) and a city name (Arlington, VA). Some Facebook check-ins also have coordinates.

Other services are specifically designed around sharing locations. For example, Foursquare is a social game based on the premise of users sharing their location. Users are awarded points for each check-in, receive offers and coupons, and can track places their friends visit. In location-centric systems like this, every single post has an associated location. Sometimes, that location data propagates elsewhere—even sites that aren't built around locations. For example, some users may choose to share their Foursquare check-ins through other social media services, like Twitter.

Auto-Encoded Location Data

When users don't explicitly share their location, there are still ways to obtain it. Photos and videos have associated metadata, which can include information about the GPS coordinates where the image was taken. This data is called Exif (“Exchangeable Image file Format”). Not all photos' or videos' Exif data contains GPS coordinates—but many do, especially those created on mobile devices (like smartphones).

Exif data can be extracted from any image online. The data doesn't appear automatically; you will need some software to view it. There are many free tools to do this, requiring varying levels of expertise.

Some are available as add-ons for your browser, such as Exif Viewer.2 With this tool, you can right click on an image, and the add-on provides an option to view the Exif data. Selecting the option opens a new window containing all metadata associated with the image. Figure 6.5 shows an example of a photo's Exif data (including encoded GPS coordinates).

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FIGURE 6.5 Exif data for a picture of a park. The “Exif GPS IFD” section includes the latitude-longitude coordinates of where the photo was taken. Other Exif data (not shown in this image) includes the date the photo was taken, allowing an investigator to know exactly when the photographer was at this location.

There are also online tools for extracting this Exif data, as well as desktop programs. Since the software options change (as do their web addresses), please consult this book's companion website for an up-to-date list of Exif-extracting software options.

Using Location Data

You've got some location data … now what? Well, the obvious answer is that you can see where a person was at a given time. However, by collecting many posts with location data, there are possibilities for much richer analysis.

To start off, consider collecting the last 200 check-ins for a user. (Note: the companion website for this book has a program you can download that will do this when the data is available.) One quick option is to plot that data on a map. Google Maps has many options for doing this. There are also a number of websites that let you easily copy and paste a list of coordinates and view the output on a map. Again, the companion website has a list of options with instructions.

Figure 6.6 shows the map of check-ins for a user who lives near Vancouver, British Columbia:

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FIGURE 6.6 A Google Map with the check-in locations of an anonymous user near Vancouver. Note the two clusters near the right of the image: one on the highway and one just north of Langley.

A number of interesting patterns emerge in this map. There are two clusters of check-ins to the right: one by the highway and one near Langley (south of the first). Then, there's a spread of check-ins to the west, near Burnaby and Vancouver.

This alone reveals a lot about the user's movements and habits. Cross-referencing these points with place-names and their types (e.g., restaurants, shopping locations, and offices) can reveal where a person works, lives, and goes out.

Another important point is that every post—whether it's a social media status update or a photo—has an associated time. Sometimes, plotting locations over time can be useful.

Figure 6.7 shows another Google Map. This comes from a different anonymous user.

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FIGURE 6.7 A series of locations gathered from one person's Twitter account, with a line connecting them based on the order they were posted. This clearly shows the person was headed west toward San Diego.

This user's last 200 posts were analyzed for location (when available), and the points were plotted on the map. A line connects the points based on the order in which they were posted.

In this case, we clearly see the person posting on Twitter as they move west toward San Diego. Reading the posts that contain these locations reveals that the user was in the process of moving from Washington, DC, to San Diego, and he posted as they drove cross-country.

Challenges to Using Location Data

There are a number of challenges associated with location data, centered around the fact that it can be hard to access.

A 2013 Pew study3 showed that the frequency of check-ins is slowly declining. Meanwhile, users who include location data with their (noncheck-in) posts are increasing significantly. Nevertheless, only about 30% of adults report including location information. This means that, for most users, location information is not available with their social media posts.

As social media use increasingly moves to mobile devices, it's reasonable to expect that more location information will become available. However, including this is an opt-in process, not an automatic one—so it is unlikely to become something we will see by default.

Privacy concerns are also closely tied to location data. As a result, some systems (like Foursquare) keep users' check-ins restricted to their friend lists. Thus, it may be hard to actually access location information in certain environments, unless you already have an existing connection with the person being investigated.

Conclusions

As more and more users access social media from mobile devices, the availability of location information—both from their posts and embedded in their photos and videos—also increases. It can be found in geotagged posts, check-ins, and the embedded metadata of images and videos. Once it's collected, there are several ways to plot it, analyze it, and discover the patterns and movements of the person being investigated.

In later chapters, we will see how to find location information in a variety of websites and in what form the data can be found.


1 http://www.socialmediafrontiers.com/2013/09/mobile-marketing-using-social-media-on.html.

2 https://addons.mozilla.org/en-US/firefox/addon/exif-viewer/.

3 http://www.pewinternet.org/2013/09/12/location-based-services/.