If you need to keep track of the location of some things like your car or your service workers you can sign up for a service that uses cell phones and GPS or you can use the APRS which stands for Automatic Packet Reporting System. Jim Whiteside demonstrates how he is using a Raspberry Pi to gather data, decode it and plot it on a map. Since the service can also send text messages I am wondering if this might be an interesting way to send some small amounts of data occasionally from one location in a city to a base location. Something like high water alarms and temperatures a few times an hour. I am not a ham operator so I am not sure if this would be frowned upon as a use of the system though.
If you are looking to get some additional information on APRS you should have a look at the videos below. If you like reading text tapr.org also has a great resource.