USGS 7.5 Quad maps' datum

[LHA]

Are USGS 7.5 Quad maps based on NAD27, NAD 83 or GEO84 projection datum?

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve

 

[Dirtmaster]

I did a "Google" search and came up with NAD27

 

[JackCrawford]

Many, if not all of the maps will indicate the datum. The one I have in front of me tells me it is based on NAD 27, but that I can line up with the NAD 83 by shifting the projection lines by a certain amount.

 

[LHA]

Thanks. I know that info is on the maps, but I no longer "see" quads; the office I currently work in doesn't have hardcopy USGS maps in it (or a typewriter, for that matter). I get them on-line. But, I'm filing out a permit app. and they are asking the question I asked you.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve

 

[eric1037]

I think it depends on the quad. Some are NAD27 and some are NAD83. If you access them on-line, they are likely scans of actual quads. However, they don't have the year or datum accessible. That and the fact that it is very difficult to find the Town, Range, and Section number is the reason I still like the paper versions.

 

[LHA]

Mine are from Terraserver and they say NAD 83, under "info".Mine are from Terraserver and they are NAD 83.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve