survey tech

Bob Having seen that this message has gotten no responses, I would offer this advice. While your statements are true, its fairly difficult for most people here, myself included, to see how they relate to geocaching. I have found that most folks here are not really too excited about all the technical aspects of geodetic surveying, but rather are in this for personal fun and adventure, so using too much technical jargon is probably a non-starter. Its also likely that a number of people were alienated by the strident tone of your first message and thus have decided to ignore your input, which is a shame, since you obviously have a lot of knowledge to share. There are only a handful of surveyors, who have identified themselves as such, that contribute here on even an occasional basis, and I have been hoping more, like yourself, would step up and be heard, so this is disappointing to me, and the reason for my response. So lets try to give the public a positive impression of our profession, by demonstrating that we appreciate their interest in surveying, providing helpful advice and answers to questions when we can, and gradually enlightening them in the process, rather than reinforcing the currently prevalent public image of surveyors as technical mavens, engrossed in mathematics and technology and out of touch with reality.

I believe the darker material is just a different mixture of grout and epoxy. As to why this was done, my guess would be that seismic activity may have moved the surface the mark is set in, corrupting its coordinate values. Still, this is highly unusual and not the typical way of dealing with such events. I have never seen one of these situations, so I suspect the practice was abandoned, making this a rare find, unless, as Rusty said, its somebody's idea of a bizarre joke. The unusually sloppy mounting would tend to support that possibility.

Good stuff, quite technical, but very informative for those with a serious interest.

The fact is that when a surveyor, NGS or otherwise, uses an existing object as a station, there is no change in the status of the object, since NGS is not vested with the power of eminent domain. In other words, NGS has no right, and no desire for that matter, to mandate that the object must remain undisturbed forever. The owner of the object still has every right to tear it down whenever they see fit. Of course, a prudent surveyor will choose an object that he thinks is likely to remain in place, but like everything else in this world, there can be no guarantee, and the surveyor must entrust his work to fate. While these kind of points established on objects, known as intersection stations for the method by which they are created, are very useful as long as they last, they are decidedly less valuable than markers on the ground, since they cannot be occupied by a surveying instument, such as a transit, theodolite or tripod mounted GPS. So the destruction of such an object is of far less consequence than the destruction of a triangulation station.

Greg Right, Hoover is not the Graceham AZ MK, in fact Hoover is much newer. Using the Maryland state plane coordinates for both stations given on the data sheets you can see that Hoover and the AZ MK are in very nearly the same direction from Graceham. Distances to azimuth marks are only approximate, but if this one is .75 miles, as the data sheet says, it may be within 500 feet of Hoover, probably southwest of Hoover. Most likely they were not aware of the location of the Graceham AZ MK when they set Hoover, or it was not found, or it was in an inconvenient spot. The key to finding the AZ MK will be whether or not the fence it was next to is still there, if not, it will be tough. Try finding Hoover first, then work your way back to the southwest, toward Graceham, looking for the fence, or the house, or their remains, along the road.

Thats correct, while some points have precise horizontal and vertical data most have only one or the other.

Cracker Thats an interesting point you make about the fact that many of these points appear unused. There are many very remote points that have been seldom if ever used, but they remain highly valuable, since they are generally the only points of their kind in such remote areas for a very long distance. If civilization ever reaches those areas, they will become precious to surveyors. Remember, in the past they had no way of knowing for sure where development would occur and where it would not. I would not go so far as to say that any markers need to be destroyed, but in some cases it is simply inevitable. Many of these destroyed points have been reset in nearby locations by local surveyors, usually in discreet locations, since they have learned over the years that vandals cant destroy what they cant see. You are right that NGS has not been actively replacing points since the 1970s, but local surveyors have picked up the slack and now have the most up-to-date records in their local files. Rusty is right about the uses of these points that he lists. Construction engineering is now the main use for these points. The points were originally set primarily to enable uniform mapping of the entire country. None of these points, however, are obsolete due to GPS. They all remain highly useful, even after the rise of newer technology. In fact, triangulation stations are typically used to anchor new surveys done with GPS.

Cracker I share your frustration, both as a hobbyist and a professional, but we all know what happens to anything that stands in the way of progress. After all, these points were set for the very purpose of facilitating progress, so its inevitable that many will fall, like good soldiers, amidst the ceaseless onslaught of development. The difference between that kind of destruction and vandalism is that surveyors are normally involved in development, so in those cases thay have the opportunity to set new points, replacing the ones being lost, before the destruction occurs. In the case of vandalism, there is no such opportunity and the area can be left without any control points as a result. I dont know about your locality, but in many places developers are fined for wanton destruction of control points

Gurubob I think you can rest easy, my friend. Originally, my concerns were identical to yours and a number of other surveyors I know felt the same way, so I made it my business to monitor the activity here. If you read some of my earlier messages you will see that all of my efforts here have been devoted to informing the public of the significance of our industry and encouraging respect for it. I have found the folks here to be sincere in their interest and there are many who are genuinely interested in learning about surveying, which is very gratifying. I have seen no indication that anyone here has engaged in harmful behavior, such as collecting survey markers, and I have done my best to foster an atmosphere in which anyone doing that sort of thing would be chastised and disgraced among their peers here. About the worst thing that goes on here is that some people are careless about their method of reporting what they find or do not find, and even those people draw some criticism from the most serious participants. So lets give them the benefit of the doubt and trust that the good ones will lead the way by passing on the knowledge and appreciation of these control points to others. Everybody Else Please understand that this gentleman does not have time to read all the messages here and his concerns are legitimate. Obviously, he would not be upset if he had not experienced problems with vandalism in the past. I hope everyone here will continue to cooperate to put his worries to rest.

In an earlier message I guessed that the oldest true NGS point still in existence was probably from the 1830s, so I imagine the ones listed here from that decade are legit and one of them is probably the oldest survivor. I was curious about the six older ones mentioned and took a look at their data sheets. The ones in California, Ohio and Minnesota are clearly bogus and the date 1800 appears to be either an error or somebody's idea of a joke. The other three are important historic points, but they are boundary points, appropriated rather than created by NGS. The one in Maryland set in 1765 was apparently first used by NGS in 1961. The one in Massachusetts set in 1825 to mark the boundary with New Hampshire seems to have been first used for geodetic purposes in 1912. The one in South Carolina, on the boundary with North Carolina, known as Commissioner's Rock, was visited in 1813 by Andrew Ellicott, who is among the most renowned surveyors in American history having laid out the boundary lines of several states during his illustrious career. Its location was observed using GPS during a joint ceremonial project conducted by surveyors from the surrounding states just a few years ago. So none of these would be considered among the oldest benchmarks, although they are marvelous old boundary corners.

Although found can have various interpretations, within the surveying community it positively conveys the message that the point remains intact and is still fully usable. Technically, once the marker is separated from its setting it loses all of its value and ceases to be a survey marker, becoming just a piece of metal. Therefore, it would not be credible to use the word found to describe a destroyed marker, even though it is true that you did find a piece of material that was once a marker or you located a spot that used to contain a marker. Its unfortunate that it appears some people may be so determined to label every marker that they search for as found, for purposes of personal gratification, that they may choose to ignore this time honored reporting tradition, ultimately diminishing the integrity and value of the data as a whole, so I would advise that this be discouraged. The dichotomy will probably persist, however, since there seems to be a fundamental split among the participants here, between those who wish to be fully NGS compliant and those who want to treat the pursuit purely as a game, so the rule will probably continue to be "to each his own".

These kind of events are fairly common, usually conducted by the society of professional land surveyors in the particular state. Some do it only once or twice a year, some more often. The points reset are usually corners of states or counties or other points with special historic significance. Anyone is usually welcome to attend as the surveyors use it as an opportunity to promote the industry and educate the public about the profession, so anyone interested should contact their state's society.

Toe The answers to your questions are: They were placed where they were with a view toward the greatest permanence. If you had to pick a spot within a certain area where settlement and development were anticipated, and you wanted it to last 100 years or more, you would have to try to visualize what was going to happen there in the future. This is what early geodetic surveyors were confronted with. They were placed when they were because it was decided that a national network was needed to facilitate the expansion of the country and the fulfillment of the doctrine of Manifest Destiny. Such historic figures as Thomas Jefferson, J. C. Fremont, John Wesley Powell and Thomas Hart Benton were among the most instrumental players in the saga. The relentless push westward that followed the Civil War made it absolutely vital that the continent be mapped from coast to coast. And so it was done. In the past, destroyed or damaged markers were very often replaced by NGS or contactors working for them, but the Reagan administration brought an end to that with its government spending cuts, leaving the NGS with barely enough funding to continue its existence. Of course, by that time its original mission had been accomplished, as all parts of the nation, even Alaska and Hawaii, had been provided with the control points they needed. What little money NGS now has at its disposal is committed to the formation of a new high tech network known as CORS, which you can read about at your convenience on the NOAA website. The surviving triangulation stations and benchmarks still represent the finest large scale control network on earth, as well as a monumental piece of Americana. I hope everyone here will respect them as such and help to discourage any vandalism of them.

Embra 553 1906 would be properly described as destroyed, since the description is of the marker itself by the NGS definition, but as I have said before, surveyors may still use this spot, since it is still clearly perceptible. Destroyed is the appropriate description because of the lack of ambiguity, not because of ambiguity. Where any ambiguity exists no conclusive determination can be ethically made. You are exactly right that a marker is just a symbol marking a precise three dimensional location, but without actually seeing the marker and confirming that the stamping on it matches the datasheet, the only way to positively verify the spot in question is through professional measurements, so without the presence of the marker one cannot ethically declare a point found. In other words, "near certainty" is not sufficient by professional standards. I suspect this may have been one reason this site was set up the way it was, because the objective of the geobenchmarking game, like the geocaching game, is to find the actual object, rather than a mere spot where it probably once was, but that is up to the participants to decide for themselves. The important point here, from a surveying point of view, for those interested in it, is that to some extent vandalism can be defeated by a wise choice of point location. This is why locations like this one are chosen, because as long as the setting remains unmoved the spot retains at least some of its value. Still, since it is not possible to find something that no longer exists, I would not call it a find and we have the vandal to thank for that.

Very good discussion guys. You both have valid points. Technically, Toe is right that it is destroyed, because all the material that comprised the mark is gone. But BDT is also correct that this spot may still have some value, since the rock in which the mark was set is still solidly in place and the exact spot where the disk was can be seen. A surveyor might still be able to verify his work by locating the hole and calculating its coordinates. If he were to determine that its coordinates are within an inch or two, for example, of the NGS coordinates, this might be adequate for his purposes, depending on the nature of the work he was doing at the time. There are, and always will be, gray areas in this business which can only be conclusively resolved through professional judgement and measurements, but the best rule to follow, from a surveying standpoint, is always to respect the potential value of any marker, or any remaining evidence of it, and make a complete report of it from which others may decide what its true status is. Remember, there should be no implication of failure attached to declaring a point not found. I have looked for thousands over 20 years and made a conclusive determination on perhaps only about one third of them. In fact it is imprudent to declare a point either found or destroyed without truly compelling evidence. This is the standard to which surveyors hold each other, although geocachers may choose to apply their own rules, suitable to their own personal goals. I appreciate both your interest and your concern for getting this right, and I encourage you both to continue to learn more about it.

Egnix I have dug up numerous markers that were merely paved over and were still in perfect condition once uncovered, so it would not be appropriate to call it destroyed. In fact this happens routinely when the cover gets knocked off by traffic. I know of some markers that have been paved over and dug up repeatedly.

This one looks particularly unstable as the rock appears to be fractured directly beneath it, and dangerous due to the chance of slipping on the wet rock and falling off the ledge. My guess would be that it was set by a novice crew member and the crew leader subsequently decided that it was too dangerous to use. Check with any older surveyors in the area, they probably know the history of it.

Note that Washington and Wisconsin are very close alphabetically. In those days paper forms were kept in paper folders in cabinet drawers. Most likely the Washington descriptions were accidentally stuck into the Wisconsin folder during processing.

Having seen this view of the point location, it occurs to me that this point may have been deemed unstable or unsafe and never used.

Rubbertoe, Makaio & Raouljan Well said, gentlemen. Thank you for leading the way in the right direction. Obviously there is no shame in not finding these points. The only shame lies in reporting incomplete or incorrect information. Hopefully everyone here will leave that to the Power Squadron and try to establish a higher standard.

Don't sweat it, nobody is relying on you. Makes me wonder how many others may be deliberately reporting false info. At least this individual was honest enough to admit it. If anyone needed an example of the confusion and misinformation that can result from participation by the untrained in professional activities, this sequence has certainly illustrated it.

The Corps of Engineers has done a great deal of work, particularly near major rivers, reservoirs and their tributaries, for the purpose of water resource management. Their markers are commonly found around large man made lakes.

Seems to me that the only credit one might get for something that does not exist would be credit that also does not exist. Given that everyone else is having some success, if you are not finding any at all you are either looking superficially or you have chosen a very poor area to look in. Its pointless to search in areas that have been completely redeveloped in recent years. The highest percentage success rates will be obtained in undeveloped rural areas. Anyway, as I have said before, each individual is free to establish their own standards and each will develop a reputation accordingly.

Boundsgoer is correct about USGS markers, but this is a USC&GS marker, unless the USGS had some C&GS markers that they used, which is quite possible. Its also possible in view of the date, 1944, that this marker was set but never used. The members of the survey crew may have gone to war and the project put on hold and never resumed.

It looks like a perfectly legitimate marker to me. I cannot give any good reason why it would not be in the database. I would guess it just fell between the cracks. The designation topographic simply indicates that it was set for mapping purposes.