Black Dog Trackers
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Posts posted by Black Dog Trackers
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I'm sure they have a database of their own, but I doubt they have the USGS marks for instance in there, since the USGS doesn't have their stuff in a database. If the Corps have every county and town and surveying company's data in a database that would really be amazing.
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I was gonna say that the number of NGS and (US)CGS benchmarks is in that data file I referenced (I think I got it from the 2006 files), but that would be wrong. We have seen several disks that said "NGS" on them that are not in the NGS database. Then there is the question of what, exactly, is meant by "owned".It would help my pitch to know how many (NGS and USCGS-owned) benchmarks there are in the U.S.
This question is almost like the famous questions cave guides sometimes get asked: "How much unexplored cave is there in this cave?".Also, do we know the total BMs per state?
There is the NGS database, and a very few other benchmark databases on the internet collected by Zhanna, and the USGS has no real database (they have all their data papers), and presumably almost all municipalities have their databases somewhere in their offices' computers, but it would take millions of $ to get all this into some super benchmark database. There's only one such effort that I know about.
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This reminded me of something I posted before, so I looked and here it is, with an answer from Deb, who said go ahead and send them in via email. Unlike Papa-Bear-NYC, I never actually went to look for one.
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The Bagley station must've been already adjusted, otherwise it would've had a N code. I assume that only D code PIDs can be resurrected in this way.
It seems somewhat odd at this technological point in time that horizontal control marks with adjusted coordinates and a designation but no description are not considered publishable. Adjusted coordinates should lead one to the spot, and if there is a monument with the correct name, then that should be enough to publish the datasheet. Perhaps the policy should be modified for such cases. The datasheet would look funny with no descriptive text but it should be findable.
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OK, here is is by state
AK 1,241 AL 16,045 AR 10,587 AZ 17,998 CA 62,861 CO 12,287 CT 4,856 DC 940 DE 1,369 FL 43,619 GA 17,393 HI 2,929 IA 6,613 ID 14,009 IL 13,712 IN 11,606 KS 10,963 KY 12,914 LA 20,188 MA 7,159 MD 12,666 ME 10,149 MI 11,790 MN 25,947 MO 12,623 MS 11,827 MT 16,082 NC 36,546 ND 12,978 NE 10,149 NH 1,734 NJ 6,531 NM 14,889 NV 12,820 NY 22,478 OH 14,724 OK 7,227 OR 19,634 PA 15,942 PR 1,188 RI 2,449 SC 17,282 SD 13,402 TN 12,160 TX 48,036 UT 7,454 VA 20,225 VT 3,141 WA 21,124 WI 10,668 WV 8,576 WY 8,240 Grand Total 739,970
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Hi pgrig -
In this page is a text file listing of the number of PIDs in each U.S. county.
It should be easy to import into a spreadsheet and get totals by state if you want.
There is also a listing of Agencies with the number of PIDs for each. Note that CGS is the direct ancestor of NGS.
Of course this data is based on the NGS database. There are thousands of other USGS disks, for instance, that are not included in the NGS database we use.
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It's a northern red oak. The leaf you picked is weird, though. The ones still on the tree look like northern red oak. Northern red oak leaves have shallow indentations and usually 7 or more lobes. Oaks hybridize often and this specimen might be a bit hybridized with something else, possibly blackjack oak which has almost no indentations and a very broad end, like the one you picked.
A black oak has very dark brown bark and if you cut into the bark, it is yellow underneath. The leaves of a black oak are quite variable on the same tree, so this one could possibly be a black oak, but I rather doubt it. The leaves aren't indented enough and the bark is too light.
As far a surveying purposes go, I'd just say "oak".
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PCFHikr -
It is a U.S. Geological Survey Bench Mark, and is therefore for vertical control (information). Its name is 51E. Pretty much as you can already see.
I don't see it in the NGS database we use. That isn't particularly surprising as there are thousands of marks like this that are not in the NGS database. The USGS doesn't really have a database. Instead it has lots of benchmark papers in file cabinets. Somewhere in those files is a notation of this marker.
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Well not all scaled coordinates are off by 150 feet. However, probably most are off by farther than the accuracy of a typical handheld GPS receiver.
I looked at nuvi 760 on the internet. It is what I call a "car GPS". My car GPS gives coordinates to the nearest second and so does a car GPS of a friend of mine. My handheld GPS gives coordinates to the nearest 1/10 second. The specs page on the nuvi 760 had a row called "geocaching friendly" and the answer for this model was "no". Precision and averaging are probably only two more minor aspects of what geocaching-friendly-no means.
I would propose that a "car GPS" is excellent for car navigation purposes but may or may not be good for providing coordinates in logs.
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Use this program to find out this kind of information. Start the program, then select the "Distance" tab. Then, in the Point1 and Point2 windows, put the same set of coordinates. Here is an example N 42 26.804 W 071 03.925What do a few hundreths of a second in lat/long represent in linear feet of difference in position around here (Mass.)?In the Distance Units dropdown menu, select Feet. Change the Point2 coordinates by 0.002 minutes or whatever you want to check. Click Go.
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Your GPSr's range is +/- 0.01 minutes in each coordinate (a range of 0.02), if I read your logs correctly. If both are off by 0.02 at the same time, then that is an error of over 150 feet. Even if only 1 coordinate is off by 0.01 minutes, then the error is about 50 feet. I think that is a sort of large amount of error for reporting coordinates. As I recall, mine moves around 0.002 minutes. Maybe it might be better if you found an averaging function in that GPSr, or average it yourself, or got a new GPSr, or even consider not reporting coordinates. Map scaling can be off by 600 feet or more, but I'm not so sure the average scaling error is worse than +/- 0.01 minutes. I think that reporting the variation observed is good and so, such a log gives sufficient information for judging the information you provide, but it might not be worth your reporting coordinates at all with that level of unaveraged variation. I really don't like being negative about this, but that is my conclusion from the data, and you did ask for a critique.I would really appreciate more help on how to report my GPS coordinates.
By the way, FizzyCalc is an excellent tool for looking into such things, as well as its more conventional uses. It is an alternatiive to NGS's program Forward, but I think it is better because it has a lot more functionality, including allowing different coordinate formats.
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TillaMurphs -
The logs look very good. On the last one, the picture with the statement "can you find it", well I didn't see it. I saw some things that could've been it, but they could be a rock too. So, to me the picture was useless.
I suggest using photo-editing to show where a mark is if it is not immediately obvious.
One option is to use microsoft paint and instructions for that are here. Other editors are fine too, of course.
I agree that if the mark is obvious then the photo is useful as is, but if there is any difficulty at all in seeing the mark, then using an arrow, box, triangle, circle, or a physical marker (like your cup) is good.
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Tilly & Billy -
It probably doesn't make any significant difference when checking the accuracy of a handheld GPSr, but just for further challenge and peace of mind
, you might want to use a horizontally adjusted mark that is a 'GPS mark' instead of a horizontally adjusted mark whose coordinates were established with older surveying methods.To find GPS marks, go to the NGS datasheet page, click on "Datasheets", then click on either County, USGS Quad, or Radial Search, and then in the "Data Type Desired: " dropdown window, select "GPS Sites Only".
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A witness post is an upright marker placed near a benchmark. The picture posted by Bill93 is an example. That one is a typical kind called a Carsonite witness post. They are orange, fibrous plastic and have a white sign (sticker) on the top that says there is a survey marker nearby. Witness posts are installed to help surveyors see where a benchmark is.
The datasheet should say where the benchmark is in relation to the witness post, like "1 foot South of a witness post". Sometimes they don't, unfortunately.
There seems to be no standard as to how far the witness post is from the benchmark or how it is oriented with respect to the benchmark's position. Sometimes they are 1 foot away, sometimes they are 20 feet away, sometimes the mark is in front of the post, sometimes behind it.
In some areas, witness posts are cement monuments about 4" square and several inches high and say B.M. or something similar. Other witness posts are 5 foot tall steel stakes like those used in gardening and a small rectangular metal sign like a license plate is mounted vertically at the top.
The position of the witness post has no geodetic value whatsoever. It only indicates that there is a benchmark near it and hopefully the datasheet says how to find the benchmark from the witness post.
Several witness posts I have found have been knocked down by mowers or whatever and not in their originial position.
Here are some examples on Dustyjacket's site now hosted by BuckBrooke.
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Hi Gmann1 and welcome to benchmark hunting!
There are thousands of benchmarks not in the database we use. You can read about that in the benchmark FAQ and in particular this section of it.
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lele2 -
Regarding reference marks versus azimuth marks, the way to distinguish them is to see what's written on the rim (usually the rim) of the disk. This one says "azimuth mark". They have different purposes; the reference mark is to help a surveyor find the main station or even to re-set it from them if it's destroyed. Reference marks are usually within 20 feet or so of the mark, usually with different but not opposite directions from the mark to give a good 'fix' on the mark's position. As andylphoto says, azimuth marks are farther away, sometimes over 1,000 feet, to provide a precise sighiting - 20 feet would be too close. An azimuth mark is to establish a direction vector based on true North (as opposed to magnetic North). With an azimuth mark vector available, surveyors can survey from the main station without having to do the work of establishing the direction to true North; they can just set up on the triangulation station and turn from a sighting of the azimuth mark.
There's no absolute rule to not include the GPSr in the closeup picture - it's just a preference that some of us have. In this case, we could see where you were talking about by reading the GPSr.
If you choose to log (not found as andylphoto says, unless you go back and find the triangulation station) ME3147, be sure to include in your log text the coordinates of the Azimuth mark from your GPSr. Note that there is no need to record your GPSr's coordinates for the triangulation station - it's coordinates are already exact enough.
Judging by the number of reference points, this is an important mark and I notice that all the local measurements are to trees and roads in 1971, 37 years ago! It would be good for one of us, perhaps you, to do a bit of re-measuring to the roads and trees for 2008.
Measuring from witness posts is helpful but they don't last as long as trees or even road centerlines, so they are not as good. As non-professional surveyors, I don't recommend measuring from road centerlines, but meausrements from trees, curb faces, fireplugs, etc. is generally not dangerous.It would be interesting to know what the 2004 log meant by "Found it (and straightened it out.)". Manually fiddling with even a millimeter of position of a mark is bad. Finding that a mark does wiggle should be noted in the log, but no attempt should be made to 'fix' it.
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What is the URL of this utility (assuming it has one)?The county (perhaps the whole state, I haven't checked) where I live has an incredible geodetic marker interactive mapping utility.
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Thanks, Difficult Run for posting this URL.
Everyone who hunts benchmarks in the suburbs of a metropolitan area should check out this website if it covers an area you hunt. It really gives one an idea of what things were like when marks were set. I have read several descriptions of triangulation stations in a farm setting and now the place is covered with suburban homes and landscaped yards.
I first made the mistake on this website of going to the oldest date before zooming in. Things were very difficult to recognize. It's best to zoom in with the most current date and then go back in time.
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greg1701 -
Well, looking in Nevada - how about Pah Rah, a real 1878 mark? It looks like only a mile from the end of Rodero Road.
Pioche Peak Monument (1881) might be an interesting find. I don't understand what boundary it is.
Diamond Peak looks pretty remote but remains a nice 1881 find.
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I don't think that Groundspeak will be including the 536,000 datasheets in to the "NGS" Geocaching database. We know about several U.S. datasheet sites (listed in Zhanna's site) that have benchmarks that are not in the NGS database and the Canada Benchmarks waymark site references some large Canadian benchmark databases and Groundspeak has not imported those either.Do you think possible to have these more than 536.800 sheets included into the "NGS" Geocaching database, in order to offer Benchmark caches
in France??? -
gperlier -
The French benchmark category description is excellent !
(I had help from http://babelfish.yahoo.com/
)I have only 2 comments:
1. There might be some benchmarks that are not included in ces fiches sur geodesie.ign.fr ou sur geoportail.fr. Could they be waymarked in this category too, if any are found? Here in the U.S., there are many towns that have their own benchmarks that are often not included in the national database, yet we allow Waymarking them.
2. The optional view from a few meters should include the idea that the point should be visibile in the sight.
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A couple more comments...
The closeup picture of the disk should have the disk's designation printing level across the picture; not upside down or slanty. Don't worry if the rim printing is turned some, or even upside down (with "B.M." on top) - the designation printing is the primary importance.
A lesser part of the identification of a disk is to be able to read the agency name on the disk. I have seen lots of disk pictures in which the person didn't take the extra effort to clear the dirt off the rim of the disk where the agency name and type of disk (like REFERENCE) are imprinted. It's really best to get the entire disk cleaned off. Sometimes it's covered by tar or cement and perhaps too much trouble, but generally it is only dirt, and a bit of extra work with a stick of wood will remove it.
Some disks should not be cleaned, for example, those disks that are vertically mounted and painted over along with the whole building. You don't want to interfere with the appearance and maintenance of the building.
Artsy closeup pictures of disks from a low angle or unusual lighting are sometimes nice, but be sure to also upload a regular closeup picture in your log.
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Well on Star Trek, Spock announced tricorder bearings for any angle, not just up to 90.
, you might want to use a horizontally adjusted mark that is a 'GPS mark' instead of a horizontally adjusted mark whose coordinates were established with older surveying methods.
Measuring from witness posts is helpful but they don't last as long as trees or even road centerlines, so they are not as good. As non-professional surveyors, I don't recommend measuring from road centerlines, but meausrements from trees, curb faces, fireplugs, etc. is generally not dangerous.
Not one, but interesting
in Benchmarking
Posted
I couldn't read that disk. After more than a year, this pic is still available to see. Surely that is sufficient time to discuss this one.