note of 10/1/2018

Global Positioning system
System that accurately determines the position of something on Earth
Including three elements
1 Satellites placed in predetermined orbits
2 Tracking stations to monitor and control satellites
3 Receiver that locate at least four satellites, figure out its distance from each. and use the information to calculate its precise location.
Why is each point on Earth Unique
A place is a specific point on Earth distinguished by a particular characteristic
Describing the features of a place is an essential similarities, differences and change across Earth
Geographers describe a feature's place on Earth by identifying its location
The position that something occupies one earth's surface
And another thing about GPS is are we really willing to share these information?
The government can track us easily but if some bad people hack in the system will they find our information easily too?
And I think it is some kinds of private  information and may not be willing to share if with others.
Before you update something, they always tell you to agree something or they won't update.
A very important thing is to read the message before you agree!