How are Google maps formed?

Question

How are Google maps formed? Are they based on satellite image solely? How are locations and places named? I sometimes see very minute details; gathering them doesn't look like an easy task.

Answer 1

They buy their data from other companies to form the maps. I beleive they purchased the majority of it from Tele Atlas. http://code.google.com/apis/maps/signup.html

Here is a lot of information on the history of it: http://en.wikipedia.org/wiki/Google_Maps#Map_projection

Answer 2

Google Maps data is based on many sources, depending on both the type of data, and the area you're looking at.

Vector (Road, Park, etc. data)

Vector data, like roads, points of interest, etc. are bought from many different companies. Tele Atlas is one of their worldwide data providers, and is a key component, especially outside densely populated urban areas.

In some areas, this data is combined with other vector data providers, like Sanborn, who do 3D building outlines, as well as combining with more local sources of data, such as organizations which collect POI data (restaurants, etc.).

In countries other than the US, data is often purchased from a National Mapping Agency; a government agency tasked with collecting and distributing map data.

In some cases, data -- especially for populating searches -- is gathered via the web, and geocoded (looked up by address) to be placed on the map.

This data is commercial; the collection aspects are expensive, and Google pays a significant amount of money to license the data for this usage. (The actual amount is not public knowledge.)

Imagery

Imagery data for Google is similarly collected via many sources. Imagery up to .5M/px (Letting you see cars clearly, but not people) is typically collected via satellites flown by Digital Globe or Geoeye. (Geoeye actually flies a satellite, "Geoeye1", which was funded by Google in large part.)

In addition, Google adds in many different public datasources, from government organizations and programs (USGS, NAIP), state and local organizations, and more. In addition, for high profile events Google will sometimes specifically pay a company to do an overflight -- this was the case for the Haiti earthquake, and is common for them to do during the Burning Man festival.

Street View

Streetview data is collected by vehicles paid by Google to drive around with special tools (LIDAR detectors + 8-way videocameras) and collect the data.

Overall, in each case, you can look at the various sources for data -- at least those that require crediting, which is not all of them -- in the lower right hand corner of any Google Map.