How do they do the mapping of the streets for GPS mapping?

Generally, exisitng map data, taken from sources such as the USGS and other cartographic services, is digitized to form the database for GPS maps. Often, if you pore through the documentation accompanying your GPS device or software, you'll find a copyright notice bearing a licensing disclaimer. Other information which appears on GPS maps, such as business names, addresses, phone numbers, and descriptions, generally is drawn from telephone yellow pages directories - something also often disclosed somewqhere deep in the documentation of the device or software.

I use Street and Atlas on a lap top, with a GPS.

The maps are made from various sources. I have found some where the roads are 300 feet off where the GPS trail is drawn.

I also use the Micro Soft mapping program. The maps on that program are better in some locations.


GPS is great for the man who does not want to stop and ask directions.

I enjoy using the GPS device.

I doubt there is any single method used to collect all of the data. Delorme (makers of "Street Maps" software and "Earthmate" GPS units) started as a map makng company years ago. They started with their own systems that produced their paper maps and add USGS data along with data from city/town GIS systems.

They also hire (or at least, used to) people to drive around and find the coordinates of things like gas stations, resturants, etc... so that they can add them as waypoints in their GPS systems. Most major chains of retailers (like Citgo, WalMart, 7-11, etc..) now collect that data on all their locations themselves and pay to have it added to GPS software.