Global Positioning System

Global Positioning System (GPS) What can your phone do when it knows where it is?

GPS You can access the GPS sensor on your phone with the following line of code: var loc := senses->current location loc->post to wall

GPS How can you write a program that tracks all of the places it has been run, and shows a picture showing all of those places when run? If you run it at school, then at home, and then at a college, you should end up with a map showing those locations by the time you’re done.

first Step It probably isn’t immediately obvious how to write this program. So, start with this question. This should be the first thing you ask yourself every time you sit down to write a program: What do you not know how to do?

locations You’ll notice that your location is expressed as a latitude and a longitude. Although you can get these values, they’re not particularly useful. You can also look up elevation.

Use this one for the homework GPS senses->current location Returns an approximated geo-location based on WiFi or Cell tower. Bad: 1 mile Good: low battery impact senses->current location accurate Returns a precise geo-location based on GPS. Bad: high battery usage, slower, requires satellites Good: high precision within 10/20 of feet Use this one for the homework

maps recipe Creating a map Adding a pushpin Displaying the map var map := maps->create full map Adding a pushpin map->add text(“bla bla”, location, ...) Displaying the map map->post to wall

assignment Write a program that keeps track of every location where you’ve run it. When you run the program, add your current location to a list, then show all locations from the list.