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@@ -7,6 +7,7 @@ TR: https://www.w3.org/TR/geolocation-sensor/
 Shortname: geolocation-sensor
 Editor: Anssi Kostiainen 41974, Intel Corporation, https://intel.com/
 Editor: Thomas Steiner 44965, Google Inc., https://google.com/
+Editor: Marijn Kruisselbrink, Google Inc., https://google.com/
 Group: dap
 Abstract:
   This specification defines the {{GeolocationSensor}} interface for obtaining
@@ -301,6 +302,141 @@ Abstract Operations {#abstract-operations}
     1.  Return |geo|.
 </div>
 
+Use Cases {#use-cases}
+=========
+
+## Categorization of use cases ## {#use-cases-categorization}
+
+The mentioned use cases can roughly be grouped into four categories:
+
+* **Foreground** operations:
+  * Getting a **one-off geolocation update**.
+  * Getting **continuous geolocation updates** (*aka.* foreground geotracking).
+* **Background** operations:
+  * Getting **continuous geolocation updates** (*aka.* background geotracking).
+  * Getting a **one-off geolocation fence alert** (*aka.* background geofencing).
+
+Note: Only the **foreground operations** were possible with [[GEOLOCATION-API]],
+the **background operations** are completely novel.
+
+Core constraints when obtaining the gelocation are **accuracy** (*how close to the
+actual position of the user is the determined position*) and **latency**
+(*how long does the user want to wait for a result*). Both are tradeoffs:
+one can trade faster results for lower accuracy and vice versa.
+
+A common theme is to first obtain a rough estimation that then gets refined over time,
+for example based initially on surrounding WiFi signals (which is fast to obtain)
+and then eventually based on precise GPS data (which may take some time to find a signal).
+
+In the following, we list use cases based on the previously defined categories.
+
+Note: The categories are not mutually exclusive and overlaps exist.
+A task might start in the foreground, then continue in the background (for example,
+while the user quickly responds to an incoming email),
+and then eventually terminate in the foreground when the user multitasks back.
+
+## Foreground—One-off geolocation update ## {#use-cases-foreground-one-off}
+
+### Locate a user on a map ### {#use-case-locate-a-user-on-a-map}
+
+A mapping application can use the Geolocation Sensor API data of a user to locate them
+on the map, essentially responding to the question "Where am I right now?"
+
+### Find points of interest in the user's area ### {#use-case-find-points-of-interest-in-the-users-area}
+
+Someone visiting a foreign city could access a web application that allows users
+to search or browse through a database of tourist attractions. Using the Geolocation Sensor API,
+the web application has access to the user's approximate current position
+and is therefore able to rank the search results by proximity to the user's location.
+
+## Foreground—Continuous geolocation updates ## {#use-cases-foreground-continuous}
+
+### Up-to-date local information ### {#use-case-up-to-date-local-information}
+
+A widget-like web application that shows the weather or news that are relevant
+to the user's current area can use the Geolocation Sensor API to register for location updates.
+If the user's position changes, the widget can adapt the content accordingly.
+
+### Alerts when points of interest are in the user's vicinity ### {#use-case-alerts-when-points-of-interest-are-in-the-users-vicinity}
+
+A tour guide web application can use the Geolocation Sensor API to monitor the user's position
+and trigger visual or audio notifications when interesting places are in the vicinity.
+An online task management system can trigger reminders when the user is in the proximity
+of landmarks that are associated with certain tasks.
+This use case assumes active usage of the application in the foreground.
+
+### Show the user's position on a map ### {#use-case-show-the-users-position-on-a-map}
+
+A user finds themselves in an unfamiliar area. They want to check their position
+so they use their handheld device to navigate to a web-based mapping application
+that can pinpoint their exact location on the map using the Geolocation Sensor API.
+They then ask the web application to provide driving directions from their current position
+to their desired destination, essentially responding to the question "Where am I going?".
+
+## Background—Continuous geolocation updates ## {#use-cases-background-continuous}
+
+### Location-tagged status updates in social networking applications ### {#use-case-location-tagged-status-updates-in-social-networking-applications}
+
+A social networking application allows its users to automatically tag their status updates with
+location information. It does this by monitoring the user's position with the Geolocation Sensor API.
+Each user can control the granularity of the location information (e.g., city or neighborhood level)
+that is shared with the other users. Any user can also see their network of friends
+and get real-time updates about their current location,
+granted they have opted in to their location data being shared.
+This use case intentionally conflates foreground location tagging and background location sharing.
+
+### Turn-by-turn route navigation ### {#use-case-turn-by-turn-route-navigation}
+
+A mapping application can help the user navigate along a routeby providing detailed turn-by-turn directions.
+The application does this by registering with the Geolocation Sensor API to receive
+repeated location updates of the user's position. These updates are delivered as soon as the implementing
+user agent determines that the position of the user has changed, which allows the application
+to anticipate any changes of direction that the user might need to do.
+The application can be in the foreground, but likewise can be backgrounded, for example,
+when the user turns their device off to save battery on a long highway route section without side roads.
+
+### Tracking sports activity ### {#use-case-tracking-sports-activity}
+
+A web application can track a user's sports activity, for example, a marathon run or a bicycle race.
+Therefore, the application does not need to be on the screen, but would be backgrounded
+while the user performs their activity, maybe with their handheld device strapped to their arm.
+
+### Real estate search ### {#use-case-real-estate-search}
+
+A web application on a handheld device can notify a user of interesting available properties
+in a neighborhood they are passing by where the property fits the user's previously specified search criteria,
+for example, 3 bedroom apartments with balcony.
+This is based on the assumption that the number of possible matches is high,
+that is, impossible to realize with geofences as the amount of required geofences would be too high.
+
+## Background—One-off geolocation fence alert ## {#use-cases-background-geofence}
+
+### Reminder and to-do applications ### {#use-case-reminder-and-todo-applications}
+
+Reminder and to-do web applications can use a geofence to remind the user to do something when they cross it,
+for example, to buy milk when they are near the supermarket.
+
+### Travel applications ### {#use-case-travel-applications}
+
+Travel applications can show venue specific data like WiFi passwords,
+the user's booking confirmation etc. only within geofence boundaries.
+
+### Ticketing or booking confirmations ### {#use-case-ticketing-or-booking-confirmations}
+
+Ticketing or booking applications can bring up a ticket notification with a QR or bar code
+once the user is near the venue of a concert or sports event or when they reach their rental car counter or similar.
+
+### Ride share applications ### {#use-case-ride-share-applications}
+
+Users can be informed if their designated driver reaches a pre-defined pickup point.
+
+### Retail special offers ### {#use-case-retail-special-offers}
+
+Given their previous consent, a user with a retailer's web application installed on their handheld device
+can be alerted about special offers or location-based coupons when they are
+in vicinity of a physical presence of the retailer. Further, the in-store experience can be enriched,
+for example, the retailer can let the user know something they have looked at before is actually available for pick up nearby.
+
 Acknowledgements {#acknowledgements}
 ================