An app can determine the device's location using GPS. How can this information and/or such information from multiple devices be used to to build software that helps people? What are the potential pitfalls of such technology? In your next creative project you'll design a location-aware app. Let's first learn some of the technology and how you use it with App Inventor.
GPS and Google Maps
1. What does GPS stand for, who developed it and where does the data come from?
2. What is latitude? What is longitude?
3. Go to maps.google.com and click on My Places then the link to maps labs (near bottom of left panel) In Maps Labs, find the lat/long Tooltip and enable it. After you do that, you can hold the shift key down on a map and it will show lat/long on map. Use the map to answer the following questions:
What is the GPS location of: 1) your birthplace? 2) Harney Science Center? 3) Greenwich in the UK? 4) Quito, Ecuador?
4. Enter the following URLs into a browser and figure out what they display:
5. Determine a Maps URL, like the first one above, that shows a map from your hometown to your dorm/apt. in SF.
App Inventor Component: LocationSensor
Latitude, Longitude, Altitude, CurrentAddress, DistanceInterval, TimeInterval
App Inventor Component: WebViewer
Put a browser in your app! Key Function: GoToURL
Use maketext block to add dynamic part (e.g., location) to static part (e.g., http://maps.google.com/maps?q=
Demo: show one's current location in a Google Map. Use makeText to build URL.
Sample App: Show location information and distance from some point:
1. Install the apk for this app on your phone. See the barcode above (the apk is attached at the bottom of this page as well):
2. Walk outside and see what the app does. Walk and see how the settings change. Play around with the options to get a feel for TimeInterval and DistanceInterval.
3. Customize: Download the zip file attached to this page, then upload it into app inventor (on My Projects page, choose More Actions | Upload Source). Make the following changes to the app:
This procedure was built using a known formula for approximating the distance, in miles, between two GPS coordinates