A Benchmark in Minneapolis?

[+JSDAFM]

I found this Benchmark while in downtown Minneapolis (7th and Nicolette) for a conference last month, I looked at a few of the other posts in the forums with links to the list of various different types of benchmarks but didn't see anything that looks like this one, any thoughts?

 

This was right outside my hotel so I had to look it up, but didn't have it on the .loc file for the area.

 

I forgot to check how close I was with the GPS. (well the building were too tall)

 

Edited August 14, 2007 by JSDAFM

[Bill93]

Pretty neat find, but too bad you didn't check the coordinates. If I read the map correctly, the longitude of 7th & Nicolette is 93 16 22, not 42 seconds, which would put it off by over a quarter mile. The given coordinates fall closer to 1st avenue and 10th St. Somebody want to check me on that?

 

The apparent precision of +/- 0.5 second should give you a position within about 100 ft north and south by 72 feet east and west.

[+BilboB]

Judging by the size of the disk (in reference to the cigarette butt), the disk must be close to 3 feet across!

[2oldfarts (the rockhounders)]

The exact coordinates of the disk are N44°58'37" & W93°16'42".

 

Unless of course the surveyor stamped the wrong coordinates on the disk.

 

John

[Bill93]

Or somebody switched it with another similar one when installing them

Or there was no surveyor involved, just someone who thought they knew how to read coordinates off a map and screwed up.

Or the original poster forgot which street corner he saw it on.

Or ???

[+Rumpled]

Looks about the size of a monument cover.

Are those initials and a number with a Star of David on the left?

Maybe SDK 19713??

or the year 1983?

 

I found this for Minnesota surveyors.

http://www.aelslagid.state.mn.us/roster.html

http://www.aelslagid.state.mn.us/LSLicNum.html

http://www.aelslagid.state.mn.us/LSLastName.html

 

Might be on one of those lists, but I couldn't find it.

 

I also google the three phrases, but didn't get anywhere.

[68-eldo]

Pretty neat find, but too bad you didn't check the coordinates. If I read the map correctly, the longitude of 7th & Nicolette is 93 16 22, not 42 seconds, which would put it off by over a quarter mile. The given coordinates fall closer to 1st avenue and 10th St. Somebody want to check me on that?

 

The apparent precision of +/- 0.5 second should give you a position within about 100 ft north and south by 72 feet east and west.

 

Google Earth puts the coordinates stamped on the disk (manhole cover?) near N. 10th St. and Hawthorn. Hawthorn becomes W. Linden a couple of blocks west and N. First Ave. a couple of blocks east. There is a Ramada Inn on the North West corner of that intersection.

 

Google Earth puts Bill93’s corrected coordinates 1433 ft. (0.27 Mi.) east of the above coordinates and 142 feet west and slightly north of the center of the intersection of S. 7th Street and Nicollet Ave. (using the spelling in Google Earth and Google Maps). There is a Marriott Hotels Resorts Suites on the north corner of that intersection.

[+JSDAFM]

WOW that was fast!!

 

I was staying at the Marriott City Center ( Google Maps of Hotel ) at 7th and Nicollet, but I'm not going to say my room number. So passed the disk every day on the way down Nicollet St to the conference centre

 

Looking back at my trip logging I did take the coords (or at least I have the best possible guess, with the limited overhead cover), took about 10-15 mins to get these.

 

N 44 58' 38.2"

W 093 16' 21.3"

Which does put it closer, I would say about 50 feet north of where it is (but thats only based on looking at Google Earth).

 

The disk is about 3 feet across, and it's right at a bus stop so very busy in that area..lots people wait (so looking a little funny taking a picture of a 'man hole cover')

 

I also saw those initials and thought something about them SDK 1983 I thought about the year is was installed but since it's really my first benchmark disk I don't really know.

 

Well I'm glad I found a good one!!

[+Klemmer]

Three FEET across! Wow! That is one heck of a bechmark ... errrr. . manhole cover.... ! If that's what it is. I've run across various "decorative" survey markers, but not that big. That must have cost a pretty penny to cast! I wonder who & why?

 

Out here in SoCal, most REI stores have a "normal" size one in front or just inside the door a bit. They do have the Lat / Long also. Never checked one for accuracy.

 

Poor JSDAFM. You will be so disappointed to find a real benchmark, only 1 - 3 inches in size! They do vary some in size.

[+Okiebryan]

Surveyors use a different datum than geocachers use. That might explain the discrepancy.

[Bill93]

The difference between the geodetic North American Datum of 1983 (NAD83) and the GPS community's WGS84 is typically less than a mete. The difference between the old NAD27 and present NAD83 is up to a few hundred feet, but in Minneapolis is about 57 feet. We are looking for an explanation of a quarter mile difference between the coordinates obtained and those stamped on the cover.

[+2/3 Marine]

Looks like a real manhole cover to me, even has the notch in the ring for a hook to fit in. Spent 33 years working in manholes for the Telephone Co, but none had a lid that nice. What I'd like to know is what's under the lid. Anybody live close who has a hardhat,safety vest & manhole hook and go pop that lid?