How does Google maps (and Earth) define highways and freeways?

[doc]

Hi,

I'm looking for the definition that Google Maps (and Earth) uses to define a road a highway (yellow line) or freeway (orange line). It'd be great if someone can point me to a definitions document (or a meta data file).

Thanks!!

[Wthrwyz]

For areas that are not yet open to editing in Google Map Maker, I would assume that Google gets that data from various third party and official sources and pretty much has to accept whatever definition those sources use.  For areas open in Map Maker, these are the guidelines Google provides for road priority.  Roads edited in Map Maker eventually get pushed out to Maps and Earth.

Using that priority list...

• Freeways and Expressways render as yellowish-orange lines
• Highways (National & Regional) and Arteries (Major & Minor) render as yellow lines
• Local roads and below render as white lines
• Various segment usages (i.e. Ramp or Parking Lot) can be applied to these priorities and will modify the base line either by changing its width or color slightly.

Keep in mind that the vast majority of the map probably hasn't been touched since most Map Maker users are focused on relatively small areas.  There is some subjectivity to the classifications so you'll find inconsistencies all over the place, but those guidelines should give you a good idea as to what Google is looking for.

Note that you will find a darker orange (almost red) color as well as blue and green in parts of the world, but these areas are not yet (to my knowledge) available in Map Maker so I can't speak as to what attributes Google uses for those internally.  Perhaps someone who lives in one of those areas can apply their local knowledge of the road network and interpret the color coding.

[doc]

Thanks! My question relates to those:

"third party and official sources"

I really need to know which sources they use because sometimes the map/earth definitions doesn't match some other sources i use.

So I need to know which sources they use, and didn't know where else to go to find that info.

Hope to find the answers here! 

[Willy Hrachovina]

We have tried ourselves to get Google to disclose their sources, but they refuse to do so. I would think they have some contact with all the state highway departments, and other mapping sources, but that is just pure speculation.