Finer points of USGS symbols

[spencer]

A friend was asking about a symbol on a USGS 7.5 minute map and I didn't know what it was, so I looked it up.

Here is a link to all the symbols used on USGS maps.

the item in question was an open triangle. It turns out they are horizontal controls (as differentiated from vertical controls - i.e. elevation benchmarks)

I thought the link might be of use to some folks...

spencer

 

[Papa Bear]

A friend was asking about a symbol on a USGS 7.5 minute map and I didn't know what it was, so I looked it up.

Here is a link to all the symbols used on USGS maps.

the item in question was an open triangle. It turns out they are horizontal controls (as differentiated from vertical controls - i.e. elevation benchmarks)

I thought the link might be of use to some folks...

spencer

Thanks Spencer

I guess I'm that anonymous friend. For the rest of you, I noticed a couple of curious marks and names on the USGS quad that covers a peak I recently climbed. Here they are:

"Moccasin"
"Bump"

If they are horizontal controls, very good. I guess the locations of these 3000' peaks was surveyed at some point. Two questions to the assembled cognoscenti:

1) Is there a physical marker on the ground at these locations? (3K baggers might have found such markers.)
2) Are the names just made up by the surveyors? Is there a database for these names? In other words, can I look up "Moccasin" and find the coordinates of this location somewhere.

Thanks

 

[MichaelJ]

USGS Geographic Names Database can get you a lot of features, though I'm not 100% sure how to search based on marker name.

 

[Pete_Hickey]

Back ni the 'good old days' (OK, now that I've said that, everyone knows I'm old) when just about the only way to get maps, was by ordering them directly from the USGS ( at $0.50/map), they used to include a page with all the symbols, with each order.

 

[spencer]

Michael,

we both looked in the GNIS and the ones in question don't occur. I find the search engine annoying to use so I have the data on my own machine and search it in my own data app. ...and I still can't find them.

below is a list of the feature types that occur in the GNIS:

Type
airport
arch
area
bar
basin
bay
beach
bench
bend
bridge
building
canal
cape
cemetery
channel
church
civil
cliff
crossing
dam
falls
flat
forest
gap
glacier
gut
harbor
hospital
island
isthmus
lake
levee
locale
military
mine
park
pillar
plain
po
ppl
range
rapids
reserve
reservoir
ridge
school
slope
spring
stream
summit
swamp
tower
trail
tunnel
valley
woods

spencer

 

[tonycc]

www.geocaching.com has a benchmark search and logging option.

You can go here to find a benchmark by Lat/Lon. You can also search by name. but you would need to know the name that was used. There are a lot of moccasins in the database, but only one in Maine. This one is called MOCCASIN IBC.

The results for MOCCASIN IBC QH0251 are here. It was installed in 1915 with high stability and last recovered in 1941. No geocachers have logged it.

BUMP IBC is two miles away with same installation and recovery dates. It was set in a boulder so the stability is questionable.

Until someone actually visits the locations and makes a report it is hard to say whether the discs are still there. Some people consider them souvenirs.


Tony

 

[Grumpy]

The remarks about stability of these survey point markers are interesting. I've long wondered about that matter, but never enough to inquire into whether it was in some way documented. We do learn something new every day. Thanks, tonycc!

G.

 

[spencer]

Thanks for the link, Tony. The benchmark data is very expansive!

Here is a map I made quickly of all the data for the southern part of Baxter State Park.

here is all the data for Piscatiquis and Penobscot Counties.

spencer

 

[arghman]

Back ni the 'good old days' (OK, now that I've said that, everyone knows I'm old) when just about the only way to get maps, was by ordering them directly from the USGS ( at $0.50/map), they used to include a page with all the symbols, with each order.

You can call USGS up and ask you to send you a copy of the brochure (basically the link Spencer posted), it's a nice thing to have & I believe it's free (or at least inexpensive).

 

[Jay H]

For those that map MapTech's terrain navigator, it has a nice thing in the HELP file (viewer.hlp) that has a nice little breakdown of all the USGS symbols you will find...

If I could post it, I would, although I could email it to folks if you want, it's a standard Windows .HLP file

Jay

 

[Papa Bear]

www.geocaching.com has a benchmark search and logging option.

You can go here to find a benchmark by Lat/Lon. You can also search by name. but you would need to know the name that was used. There are a lot of moccasins in the database, but only one in Maine. This one is called MOCCASIN IBC.

The results for MOCCASIN IBC QH0251 are here. It was installed in 1915 with high stability and last recovered in 1941. No geocachers have logged it.

BUMP IBC is two miles away with same installation and recovery dates. It was set in a boulder so the stability is questionable.

Tony

That "Moccasin" is my Moccasin. I looked it up on your link, put the Lat/Long into Topozone and got Moccasin

So I guess we have a new resource for identifying points.

Until someone actually visits the locations and makes a report it is hard to say whether the discs are still there. Some people consider them souvenirs.

I know 3k baggers have defiunately visited those peaks. Any of you out there remember? "Moccasin" is Middle Caribou and "Bump" is the 3320'+ peak across the valley to the north, about a mile in on the ridge northeast of Boundary Monument 410. (Edit: "Bump" is at elevation 3420'+, not 3320'+)

I do have a question on this look up. I assume "geocaching.com" is a non-govermental site set up by geocaching hobiests. Is there a government database that this site is using for theor search?

Thanks

 

[spencer]

PB,

that site uses the underlying data from the National Geodetic Survey.

that's where I got the data I used to make the maps above.

 

[paul ron]

Perhaps you are mistaking benchmarks for horizontal controls?

See this site to get info on HCs...

http://www.tpub.com/content/engineering/14069/css/14069_437.htm

 

[dms]

PB, I have been to both the Bump and Moccasin, obviously we were looking for registers, not discs, so our eyes were fixed at about 6 feet off the ground. But neither one had a boulder or any kind of rock at the summit that we could see. I will say that at both summits, the vegetation was, shall we say, bountiful! Maybe a metal detector would have been useful.

 

[tgoodwin]

Having worked for the USGS as a field assistant in 1976 on the metric maps of the Adirondack High Peaks and in 1978 in eastern Mass. including Cape Cod I can perhaps add a bit of information. Just remember, I was a "field assistant" and not a trained surveyor.

For map makers, horizontal position is far more important than elevation in making accurate maps. Those of us demented souls who deliberately trudge uphill for recreation want to know how high we must trudge, but a map maker wants to know first of all how far one summit is from another. Thus there are a variety of horizontal controls (shown with the open triangle that started this thread) shown on each map. A "main station" such as Cascade or Hurricane in the ADKs will have a brass benchmark with two reference marks - brass disks with arrows pointing toward the main benckmark. Other points - sometimes labeled "flag *" - will be nothing more than a drill hole in the rock where a flag once was placed. No metal detector will help you find a drill hole covered by 50+ years of leaves and moss. A currently visible example of a drill hole point is on the summit of Mt. Colden where there is a drill hole surrounded by a chiseled triangle.

Mt. Marcy was also a main station for horizontal control, but today the main benchmark (that was actually about one foot below the summit) and one of the two reference marks are gone - victims of souvenir hunters. One reference mark remains, pointing towards the former location of the main mark.

Finding the triangle symbols on a map can be a starting point for some interesting explorations since a triangle indicates that, at the time of the survey, there was a view from that point. How it might look now is another question, but still perhaps worth the trip to find out.

 

[Davehiker]

There are two horizontal controls marked with open triangles in my area that seem to be named for the landowner or a family that lives near the point. I've never found a marker on them, though I never really looked hard.

 

[arghman]

Having worked for the USGS as a field assistant in 1976 on the metric maps of the Adirondack High Peaks and in 1978 in eastern Mass. including Cape Cod I can perhaps add a bit of information.

how does that actually work in the field? does one of you go to one spot & another to the other spot & take distance/angle of elevation/azimuth readings?

 

[JOD]

Survey Control

Some states have websites with survey control information. Survey control is generally maintained by the states Department of Transportation. Maine is Maine DOT Maine Survey page, New Hampshire is NHDOT, Massachusetts is MassHighway.

I found this for Moccasin IBC, and this for Bump IBC

The National Geodetic Survey has a site to search data and submit recovery information.

Have fun with the maps.

Jim

 

[RoySwkr]

1) Is there a physical marker on the ground at these locations? (3K baggers might have found such markers.)
2) Are the names just made up by the surveyors? Is there a database for these names? In other words, can I look up "Moccasin" and find the coordinates of this location somewhere.

I believe that there were markers at both places, at one we had to remove a cairn which covered it. I seem to also recall that there were plastic sheets extending out 3 directions to make it more visible from the air, but that was 20 years ago and they were probably designed to be biogradable. (There was a similar one on Signal Mtn VT.)

Someone has already posted the NOAA site, the names on the maps are not necessarily in the database so you are better off searching by lat/long. You can select horizontal or vertical controls or both. On the ground a horizontal control should have a small triangle in the center but a vertical-only control may not. Of course the control may not be a brass disk at all, for instance on Monadnock the official summit marker is a drill hole not the brass marker a foot away, neither of which is on the highest point.