Black Dog Trackers

billwallace - Cadastral marks, if they are disks, can be waymarked in the U.S. Benchmarks Waymarking category. To make a waymark, you provide the coordinates from your GPSr and upload a photo or two. (Once there, the photos can be linked into this forum if you like.) There are already quite a few cadastral marks in the category.

It's been a while, but I put this capability in NGSREAD. It now has optional labeling (ngsread /labels=settingcode datfile.dat) so that it will show the setting code as the label on each benchmark in a .kml file for viewing with Google Earth. Clicking on a benchmark's icon will show a datasheet with all the recovery information and other data for that benchmark.

Hi SpankyBanksy - Groundspeak also runs the Waymarking site, and on that there is a Waymarking category for U.K. and Ireland Trigpoints. Unfortunately, Groundspeak did not decide to parse in the trigpoint databases, (including many others here in the U.S.), so if you find any, you enter the coordinates and description. It does provide a place to log finds though, as well as the usual challenge of finding and visiting the trigpoints as is done here. If you click on "show additional information" on the U.K. and Ireland Trigpoints category page, you will see some more related URLs. There's a little over 2 thousand trigpoints logged (waymarked) there already.

billwallace - If what you want is a county's worth of PIDs in a .dat file then get that data here. You pick a state, then pick a county. Click on "Get Marks". A list of stations will appear. Click "Select All". Click "Get Datasheets". If you're lucky, there will be less than 1,100 PIDs in the county. Put your mouse on the first "1" at the left of the screen where it says in the same line "National Geodetic Survey". Mark all the contents to the last line of a datasheet. Click File, Save As to save it as a .dat file. Depending on what program you're using to read the .dat file, you might be able to get away with just doing a Control-A and save as a .dat file, but some programs might be 'allergic' to the extra stuff at the top and bottom of the file. You could also edit them out with a text editor. If your county has more than 1100 PIDs, then first sort by PID and then mouse-over just some of the file, picking some PID to stop and start the next group. ===== I wish the NGS would create .dat files for counties and whole states automatically every day. It seems rather odd that the archives are 3 years old. How many users are really satisfied with 3-year old data?

Bill93 - Yes, I met John H. years ago (the 80's), talked with him about weighting. Both of us agreed that the S&S example could use better wighting. Of course, S&S's main objective was to do an article to introduce the matrix least squares method, not to get into the esoterics of weighting. It would be like an article giving woodworking plans on a chest of drawers, and then another article on wood finishes. The simplistic weighting in S&S will work, and even if you alter it an put in highly accurate seperate weighting, the results are not goiing to change a whole lot. I did put better weighting in a program based on Schmidt and Schelling. I didn't write the program originally, I just modified iit. In order to get good weighting, you must do some controlled experiments with your angle and distance measuring equpment. Different equpment has a different random error rate. To do a least squares matrix solution, the program you write must first be able to go through all the data and find all the intersections. Then each group of shots between 2 intersections is a string. The solution of the matrix gives the coordinates of each intersection in the net of strings. Your program will have a starting point, and the matrix solution will be based on that, but you might need an option to hold 2 positions constant, I don't know. If you're doing a map that needs to show all the shots between strings, then you need to do this: The next step is to compare the vectors of original string and its adjusted string (in whichever direction you choose). Each shot's measurement(s) must then be ratioed so that their sum vector is the same as that of the adjusted string. You can choose to not change the angles and only change the distances, or change the angles and not the distances, or do both some way, your choice. (I think one of those is called the compass rule.) Do that for all the strings. However, for some surveys, like perhaps the ones you're doing, the intermediate shots' locations are unimportant, so you don't have to do that stuff. The way we did surveying is to do backsights for every shot and enter the average into the comptuer, not re-do the whole survey from a different direction. (You may wish to take into account the statistics of backsighting in your weighting. :-) ) If you do the same suveys twice from different directions, you're going to add a lot more complex statistics to the matrix unless you use the same station names for the intersections when you re-do a survey. With that simplification, you will just end up with one adjusted string between the 2 locations because the matrix solution just gives the coordinates of the intersections, even though it started with 2 strings. But managing that might make your program more complicated.

Bill93 - I recommend that you get a copy of this publication. It gives the math and an example with a matrix. It is a good starting point for understanding least squares solution by matrix and how to set it up and solve it. I found it to be very clarly written (well, the last time I read it was many years ago), and the example is easy to follow. Many people have used this article as a starting point for writing their own least squares closure program for survey data analysis. It's a short article, only a few pages, as I recall. The place to order the publication is here, and it's $3 if you order by phone (I just checked). The one to get is Volume 32, number 3, as the first URL above says. The handling of string weighting in the article is a bit simplistic, but one can improve upon that without changing the basic information provided in the article, and can optionally be done at a later time after getting your program working. The weighting presented is by shot length only which will work fine, especially if you do a few experiments to get the value for your equipment. The improvement I'm referring to is to have separate weighting by instrument; tape, compass, clinometer. A closure will happen with either type of weighting, of course. Your program should accept the data as taken. With matrix solution, the order doesn't matter. Of course, if you take several shots between two intersections, they must be kept together. When the matrix is solved, each string will have a level of error associated with it. If one is out of tolerance, re-survey it, or just find a transcription error if you're lucky. The distribution of error is done by the matrix solution, with the strings with the lowest error level having the most weight. The article describes that too, as I recall. Beware, you might find yourself stepping into a big project. :-) Setting up and solving the least squares is the easiest part. Getting the program to work through the data and set up the survey strings is the more time consuming part.

Benchmark Blasterz - Your detail oriented standard of proof is quite appropriate. Although we have fun finding them, benchmarks are serious business in themselves and a goal of many benchmark hunters here is to get enough experience with their accuracy of finding to go ahead and make recovery notes to the NGS site.

newfane1 - Here is the part of the benchmark FAQ page that pertains to your question.

Hi TillaMurphs - I will attempt to answer your questions. 1. No. Go ahead and try looking. 2. Yes. 3. These out-of-area prefixes certainly indicate no datasheet. However they are not a 100% positive indication. If you download any state you will find some with datasheets. I seem to recall that someone in here submitted handheld coordinates to the NGS on a couple of these and that engendered a datasheet being made for the marks. 4. I have watched when this topic has come up before and have yet to see the NGS representatives say anything definite about these out-of-area prefix stations. I'd say to go ahead and look for these marks and if you find any of them, send your information to the NGS complete with your handheld readings for the marks. The NGS might make a datasheet for them, given handheld location information.

Could you post that link here?

kayakbird - If you want to hunt that way, you can post your benchmark finds in the U.S. Benchmarks Waymarking category. Good hunting!

I haven't seen the NGS photo requirements link posted here lately, so here it is. Bear in mind that these instructions are for surveyors establishing benchmarks. As far as I know, the NGS has yet to explicitly publish a version of this for recovering benchmarks, however the same kind of format guidance was stated by Deb in her forum post.

surveyor job opening photo humor. I couldn't find the original, but there's numerous sites.... On any web search engine, put Surveyor "Must be fast on your feet" in the search window and click Search

Generally (VERY generally) the witness post faces the mark. I guess the theory is that if you find the mark and wonder what it is, you look up and see the sign. I'd say the probability function rises very quickly from 1 foot to 2 feet and then tapers off asymptotically going to half-maximum probability at about 6 feet away and on down from there to a very low probability after 12 feet. Short answer: I don't know. Too bad the NGS didn't use a standard _variable for distance to witness post.

I didn't see any politics or political leaning either way or any political message in there at all. It was just a joke as far as I could tell. While I was reading it, I thought, is this April 1 already???

I musta missed the poor taste part of the humorous note. What part was it?

The old topic is here. Here's a description of the TLM 100 FatMax Tru-Laser distance measurer. Is that what you have, Patty? It's available at amazon.com, I see. Trimble makes one too.

Looks very interesting. I just saw one with free shipping on ebay for $109. The round-the-corner pythagorean mode looks like fun although how do your make sure you have a right angle?

Z15 - That's a hilarious story!!! She probably figured she had a captive audience for the rest of the day.

To find some dam sites, use the USGS GNIS site. Click Feature Class to find Dam. Put Wyoming in the State box. Click Feet, enter 6400. Look at the second to last results page.

laramie_falconer - There are 2,301 Bureau of Reclamation (BOR) survey marks in the NGS database. Nevertheless, there are probably many more that are not included in the NGS database. I saw 21 monumented in Wyoming but after looking at the datasheet for each one, none match yours, which was in no way surprising. Maybe it wasn't in Wyoming? By the way, I did a database fiddling last Janurary and BOR has: 277 recoveries average 13.4 years since last report of those... 248 found (12 of which were after a not-found report) 29 not found 2301 monumentations 1072 dated monumentations (of the 2301) The Wyoming 21: MQ0408 MQ0530 MR0741 NQ0476 NR0380 NR0386 NR0387 NT0667 NT0668 OV0325 OV0326 OV0328 OV0335 OV0371 OW0094 PX0123 PX0127 PX0133 PX0135 PX0159 PX0313 ===============

Okiebryan - Heh, thank you for posting those questions on POB. Hopefully people there will enjoy answering some of them. If they do, could you provide a link? foxtrot_xray - I take it that a horizontal traverse station is a secondary kind of horizontal control - based on a more rigorously set mark, but I don't know. tosborn - Thank you for answering some of the questions. Hopefully this topic will get a pretty good assemblage of such answers. DaveD - interesting lore about gravity and magnetic stations. So those are for mapping those creepy magnetic lines and geoid waves. By the way, the URL you gave doesn't operate. Klemmer - ah more interesting lore - the DoD and NASA connection - for navigating the crazy geoid, eh? I don't think there's any such thing there. Just some very old mountains - perhaps someone was wondering how deep they go or something.

I'm attempting to further my education here, so I thought I'd expose my level of ignorance and ask a few questions.... I thought I knew a lot about surveying and the uses of survey marks, but after reflecting on it, I find that I really don't know much about them. Hopefully some people who know more than I can explain some or all of these things. Horizontal control and Vertical control marks are aspects of geodetic surveying but Cadastral is not. Geodetic surveying determines the position of points with respect to the Earth's geoid, longitude and latitude. Cadastral surveying only relates to local and distant borders, I think. Techniques I think I understand very basically how horizontal control is done - either by measuring distances, azimuths, and vertical angles, or by using GPS, and then using an adjustment program to resolve a net of such control points.. Vertical control also uses the measurement of distances and vertical angles, or perhaps just distances and something else, I don't know. Whether or not angular measurements are used at all is unknown to me. In any case, it is also adjsuted by a computer program to resove a vertical control net. Cadastral surveying is even more of a mystery to me than vertical control. I can find no explanation on the internet as to how it is done. Certainly distances and horizontal angles are used, but I don't know what's done about the vertical component. Does a property on a mountainside have more surface area compared to the same 'size' property on flat land, or is it the same surface area? I don't know if cadastral surveying can make use of GPS technology. Another puzzle to me is why the central and western U.S. has a lot of cadastral marks while the eastern third doesn't seem to have many cadastral marks. I realize that the borders of the western 2/3 of the country tends to have been laid out on grids, but both the whole country has borders. It would seem that the more complex eastern third would be more in need of cadastral marks. Uses It's pretty obvious that geodetic control is involved with mapmaking, and cadastral surveying is involved when property (private or municipal) borders and boundaries need to be established or re-established. Beyond that generality, I'm not sure of exact uses, for instance, if a new building is to be built, is geodetic surveying or cadastral surveying required, or both? Railroads and bridges tend to have vertical control marks. Is it that no one cares if a bridge is moved downstream a bit by a storm or car accident, just so it isn't any lower or higher? Is it a grade issue, where car roads and railroads need to be messured in terms of vertical distance for some reason? Are the marks established to help build these roads, or are they established after construction, as some aspect of maintenance? I can see that if a building is to be built, it must be located well within its proper property boundaries, and cadastral surveying does that, but what then are geodetic horizontal control points for besides making paper (or computer) maps? Do cadastral systems ultimately depend on geodetic control? Even more obscure Even more obscure are magnetic stations and gravity stations. Are these remnants of scientific research projects? There are gravity anomalies that warp the geoid but what do these stations do? There's a mountain road vaguely near here that has at least 20 gravity stations on it. There's no mining there anymore, if there ever was much, so what was the curiousity that was or will be satisfied by these gravity stations? What does a gravity station do that a vertical control bench mark does not do?

This is one of those cases where the same physical mark F 547 RESET has two identities and hence two PIDs: 1 ) a vertical control mark (established 1950 by ATSFRR) FL0090 2 ) a horizontal control mark (established 1951 by CGS) FL1906 Both are third order and both have some note about not being checked. The dsdata.txt reference doesn't seem to explain much about "NO CHECK" - it isn't even listed as one of the options on the coordinates line. The 6-figure seconds values listed for the horizontal control mark's horizontal coordinates is not its actual precision as physically measured but instead the (nominal precision) output of the adjustment program for this mark.

It looks like there may be more in the "Other Databases" URLs included here.