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KSearl
09-16-2010, 11:19 AM
So, I have always been fascinated with USGS Bench Markers that can be found at the summits of many mountains. I have done a few searches, but really can't find much logistical information on them. I'm hoping someone on this forum may have some knowledge of these and may be able to help. This is purely for my own curiosity (and maybe other forum members).

1. What makes a mountain worthy of one of these markers? I see many mountains that have them and many that do not, but there doesn't seem to be a rhyme or reason to them that I can tell. For instance, I believe Washington, Lafayette and Liberty all of have them, but Osceola and Lincoln do not, why? I've even seen smaller peaks with no real popularity, such as Iron Mountain have them too (although, I think this mountain used to more popular back in the day when it was a ski mountain).

2. Where can I find a list of USGS markers that exist? Is there a database some place that can be accessed on line? I'm wondering more specifically for New Hampshire.

Again, just questions out of curiosity...hoping someone has some insight!

Thanks,
Karl

spaull
09-16-2010, 11:24 AM
I don't have an answer to all of your questions, but I know that Land Surveyors use them when doing surveys that require elevations. Because of this you find them all over the place, not just on mountains, but on rocks in towns or on seawalls and the like... I believe if you hit the USGS website or call a surveyor they could tell you.

mahony
09-16-2010, 02:36 PM
I think Osceola has one, but it is not on the ledges with the views it's back in the scrub (that is from a discussion on VFTT not my own seeing it).

I think (I just guessing here) the idea is that hills with significant "view" to other reference points are marked. So Lincoln wouldn't need one because every practical view from Lincoln can be seen from Lafayette? Sorry I don't really know, but I'd like to find out.

redthorne
09-16-2010, 02:45 PM
As a geocacher (treasure hunting with GPS) and USGS mapper, I suggest reading this page that the geocaching folks have put up. We do actually 'hunt' benchmarks.
http://www.geocaching.com/mark/default.aspx

In general, benchmarks are uses for points of reference for mapping and marking major land, architectural, and other manmade features. There are also benchmarks that are used to triangulate specific points, show north, and mark property boundaries. Who decides what features get one? That I do not know, but I surmise a panel of mappers that work for the National Geodetic Survey.

The national geodetic survey website has more 'technical' information available, as well as a searchable database:
http://www.ngs.noaa.gov/INFO/WhatWeDo.html

Bill O
09-16-2010, 08:13 PM
Benchmarks are everywhere. I was into geocaching a few years ago and their website has a database of all known benchmarks in the country. They aren't always nice plates embedded in rocks. In my town I have found markers that were embedded in the side of a church, on a boulder at the fire department, and a bridge abutment. They are also water towers or church steeples, or a simple metal pin pounded into the sidewalk.

I agree with mahony's idea about mountain tops. Benchmarks are used for map making and a peak is an easy immovable object that can be seen from many locations, a good reference point...and a good place to see other reference points.

Brad
09-16-2010, 08:55 PM
We used to survey off known points - benchmarks. If you know the coordinates of a specific spot, then finding the coordinates of another location can be done using the benchmark as a starting point. The result is your coordinates are then more accurate.

KSearl
09-17-2010, 09:14 AM
Thanks everyone for the information. I always thought they were used to mark significant locations, such as the summit of a mountain. I guess it makes more sense that they would be used more for surveying and mapping, since it is the US Geological Survey department. I still enjoy finding them on the tops of mountains. I noticed there is actually two on Mt. Lafayette. I still need to try to find a list of NH mountains that have them. If there is one on Osceola, I missed that one...guess I'll have to re-climb it. Also, I've seen pictures of one on Mt. Cardigan, which I also couldn't find.

You guys have me thinking I should get into geocaching too. Sounds like something I would like.

Again, thanks for the responding and the information.
Karl

mahony
09-17-2010, 11:01 AM
Thanks everyone for the information. I always thought they were used to mark significant locations, such as the summit of a mountain. I guess it makes more sense that they would be used more for surveying and mapping, since it is the US Geological Survey department. I still enjoy finding them on the tops of mountains. I noticed there is actually two on Mt. Lafayette. I still need to try to find a list of NH mountains that have them. If there is one on Osceola, I missed that one...guess I'll have to re-climb it. Also, I've seen pictures of one on Mt. Cardigan, which I also couldn't find.

You guys have me thinking I should get into geocaching too. Sounds like something I would like.

Again, thanks for the responding and the information.
Karl

For Osceola see http://www.viewsfromthetop.com/forums/showthread.php?t=23181&highlight=usgs+osceola particularly post #14 for the location of the survey mark