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Everything posted by evenfall

  1. This is a good one Dave, UW7907 STATION DESCRIPTION UW7907 UW7907'DESCRIBED BY COAST AND GEODETIC SURVEY 1964 UW7907'STATION ANCHOR 1964 (ECC) IS LOCATED IN THE IMMEDIATE VICINITY OF UW7907'STATION ANCHOR 1964 AT THE WATERFRONT IN DOWNTOWN ANCHORAGE, ABOUT 3 UW7907'FEET TO SEAWARD FROM A POINT MIDWAY BETWEEN TWO PEDESTAL UW7907'MOUNTED TELESCOPES STANDING ABOUT 6 FEET APART NEAR THE EDGE OF UW7907'THE CLIFF OVERLOOKING KNIK ARM. TO REACH, PROCEED TO STATION UW7907'ANCHOR 1964 AND THEN TO THE TWO TELESCOPES ABOUT 115 FEET BEARING UW7907'231 TRUE FROM ANCHOR 1964. THE STATION WAS NOT MARKED. This is an eccentric station. For some reason, the surveyors could not turn angles the way they wanted or needed from Station Anchor due to view blockages or some such reason. Perhaps Station Anchor was initially monumented before something was built in the way, or perhaps they used a Bilby Tower and this crew did not have one. So this crew created a compromise because the station could not be occupied and moved to where they could do the work. They left future Surveyors a way to re-accomplish their work. When we cannot occupy a station in the usual manner, we can sometimes occupy it eccentrically if need be... It is a way of getting a survey done when it needs to relate to the Station in question in a specific locale but it adds a lot of number crunching to the mix. I have also come across stations with Eccentric work done on them. One interesting one was where an old water tanks center standpipe had been the Station. It was really an unoccupiable Landmark and Third order at that as I recall. An ECC (eccentric station) had been surveyed under the same name, with the ECC tagged onto the name upon the very same tank. The Brass disc was actually monumented into the concrete base of the Water tank with ECC in the name and the actual station set up position was not on the ground but rather, the position used to survey was directly above, half way up the water tower's legs on a platform built of wood across the braces. It was surveyed in to First Order Standards. It all Happened on an Army Fort and the Tank was removed in the late 50's. A reset was put in about 70 yards away. The Tank Gone, Army engineers asked the CGS to come recover their discs, which they did when they placed the reset. The Azimuth Mark existed up until just a few years ago but was never very useful to the reset and all that remains of the station is but one lone RM... The place isn't even an Army Fort anymore. Back then you sort of had to be crazy brave to do the work, and today OSHA would literally fine you until your grandchildren had to finish paying if you climbed up there and got caught. Would I climb up there?... Heheheheh Surely You Jest! The reset is still there too, along with it's 2 RM's however is taking it's lumps from the occasional lawn mower... Interestingly the 3 RM's have a better safer future... Yes you can Log it if you can find the spot, and since you need only a Compass and a Tape measure to find the spot, there you go. It has a PID, so there you go. Would I do a Re-Survey from this Location? No. It is not stable enough for our work these days. But just the one time they did, they may have accomplished getting numbers that were somehow important to Geodesy. The real question, and my Tongue is in my cheek, is how do you destroy a mark that never existed? Amusing... Rob
  2. Blackdog, I have had many PID's removed from the NGS database which are in the Geocaching Database. Yup, Sometimes you can prove something is destroyed. On the other hand, some marks may have not been in the system when Geocaching's copy of the DB was made due to any number of administrative reasons... We are learning that nothing seems to stay the same forever. Rob
  3. Stude, Nice Truck! Anyhow, you can find information about the Bearing Trees on the BLM Website. http://www.blm.gov/cadastral/meridians/meridians.htm And no, they have no need to be reported, they just are handy when a Surveyor needs to use it is all! they know how to find it if they need it. Rob
  4. Renegade, You probably already understand this but it is worth a refresher... In the case of Latitude you have : The angular distance north or south of the earth's equator, measured in degrees along a meridian, as on a map or globe. In the case of Longitude you have: Angular distance on the earth's surface, measured east or west from the prime meridian at Greenwich, England, to the meridian passing through a position, expressed in degrees (or hours), minutes, and seconds. So the equator fixes the frame of reference and the Sun is what determines the Equator. The Poles of the Earth fix the other frame of reference. The system of measuring all this is called a Polar Coordinate System, which is a grid that allows angular measurements on a curved surface and rotates with the Earth. Circular Trigonometry is used to figure it out. It is not dependent on the surface of the earth as a reference, but can and does allow for measurements which are both of Earth and moving on earth. The equator and the poles are where they are and the earth moves rotationally through and around them. The surface of the earth moves in a manner relative to this grid largely due to Tectonic Plate movement. This would include Earthquake Fault lines such as the famous San Andreas, Gravitational changes and shifts, Volcanic Movement and explosions, (remember the current swelling under Mt. St. Helens and the explosive results of the same?) Geological movements such as sinking and slipping such as Glacial and Mud slides, and believe it or not sometimes dissimilar earthen materials simply reach a point where they slip due to weight and pressure. These ultra huge earth slips have been attributed to tidal waves just as tectonic plate movement has and that leads us to other forces which are not from geological forces but can affect them are Huge Tidal Waves, Weather, Tidal actions and river erosion, not to mention the Human Factor's man made earth moving efforts. All these factors affect the Earth Surface and are constantly causing changes to that surface relative to the frame of reference. Klemmer, Writing for a living is something I don't currently do, but I have been wondering if I would enjoy it. I do enjoy the writing that I currently do, and have been musing about the future of it a bit. I do enjoy helping out here in the forums. Thanks for asking, Bicknell, As you know, I am not the Briefest writer around. I fear I may have already put the Wordy Surveyor upon your question. I sure wish the answers were simple, but the simplest answers seem incomplete and only sprout more questions... I hope we went where you had hoped this would go. Rob
  5. Bicknell, You said "What I don't understand is what impact this has on understanding the geoid and making maps and such. Sounds like something a geologist would be more interested than a surveyer." The impact is that Gravity distorts the shape of the earth. See The Earth, as you may know is not a perfect Sphere, it spins on it's axis and this centrifugal force distorts the Sphere into the shape of an Ellipsoid, and well, it doesn't stop there. This ellipsoid is further acted upon by the force of gravity, or distorted by gravity, so much so that we have found that the ellipsoid is not smooth, it is lumpy. This really goes beyond geology, and in fact it is part and parcel a determiner of geologic development. Further we have found that gravitational forces are not static, they change and is so doing the surface of the earth is constantly changing. To add, The NGS, Decades before the DOD and NASA came along, was studying Gravity, and their work was used by DOD and NASA to aid the studies they have. A lot of what is studied and when goes along with the era, and the mission of the agency at the time. DOD first started studying Geodesy for Space purposes in the late 50's around 1959. The USAF had Geodetic Squadrons for about 35 years... Missiles you see, need to know where their landing strip is... Oh, and how to get there from well, you know. How it matters to the Surveyor and the Map is that the map is supposed to be a replication or representation which defines the face of the Earth on a smaller scale, or what we should find and measure when we are at any given spot on a map. The Surveyor is the person who is responsible for taking the measurements. In the Chicken Egg theory, the Surveyor has a reference point, and in a way the map will try to represent it, but when they observe the point they may observe that the reference has changed. So not only does Gravity interest the Geologist, it interests the Surveyor and the Geodesist as well. It affects everything in what seems like a relative uniform way. When precisely measure it, it really isn't as uniform as we think. The way we find that the gravitational references affect things the most are in the vertical. The vertical changes can of course affect horizontal locations as well, but the grid we measure with is fixed, it doesn't move. he earth moves. Latitude and Longitude are more stable than the surface of the earth. When we compare movements of the earth as compared to the static measure of Latitudes and longitudes as well as Orthometric, Ellipsoidal and Geoidal heights, We quickly see that the Earth is always on the move and that very much matters to all the different scientists and observers involved. We study it to keep track of all the points on the Earth which we have assigned importance to, and, there are a lot of them. If I can help any further Please ask, and in the meantime, if you are interested in some of the science behind it, the NGS website has Many papers on Gravity and Geoidal work, and Google can hunt up more if you are interested. It really is more interesting and better reading than you might think. Rob
  6. Perhaps, But it is how the scaling takes place for those who may wonder what the process entails, and the accuracy can be affected by the scale of the Map. It is hard to say what they had for a map to scale from in 1930 something, or how much detail that map may have had back then, Eh? We can know that a lot of Mapping and Topo work has been aided greatly by the use of Aerial Photography so pardon me while I go take some large format photos in my old Ford Tri Motor... I cannot do much beyond correct the errors I find. I never really know what caused them, as it can be so many things. Some times I learn what happened as I correct them, Other times... well I just take it on faith and correct them anyway. I think +/- six seconds is a give or take of about 300 feet on either side and that would be a total of 600 feet of possible error, but these things are never that mathematically clean as a rule. We just have to take them as we find them. In nearly every case, I think a GPSr Waypoint can help that out a lot. The running of numbers in a calculator and then giving those numbers too much credence can cut us off from a lot of reality. It is like the weatherman saying it will rain tomorrow, and yet when tomorrow comes. It never does. We have just got to go on what we have. It could be a different Building, it could be a lot of things. In Harry's defense, he did say he found the Building and that it was easy to find. He knew that Rockaway is not a City but was once a Borough with a city hall, but probably not anymore. It may have been lost due to building remodeling. The Minute error could be from any number of reasons. People can and do make judgment errors all the time. Ultimately it will not matter if it is not found. If so, then well it is not found. Simple and tidy. Beyond that, I too have found errors I could not explain and further more, because of the nature of the error, I could not correct the data sheet either. Station Mark still lost. Oh well. Come see, Come saw. Que Sera, Sera. Rob
  7. Black Dog, You are in a way correct, It won't be you or I who decides, But the Survey Field is age old, and is arguably a profession that shares it's spot with the oldest of all professions in the world. It has a Culture to it as you may have guessed and it is serious about following standards and practices. It is the adherence to following these standards and practices properly that make the system work at all. In other words it has already been decided and has been that very way for years before you or I came to play. I therefore do not see this as an open Question or just my opinion, I see it as the way it is and has pretty much always been. If You don't think I am correct in my thinking, Please refer to the FGCS Bluebook and read it over, then see if the methodologies are not extremely detailed and clear. Those rule have been in constantly upgraded development for years. We as fellow Surveyors know that we work best in this Culture if we just fall in step with it, and that is why we do this, we follow the ways of the culture. Simply put, the adage is do it this way or it will become severely screwed up. We, not being the ones who go down in history as being the ones who screw something up "get it". We fall in step with the norms and follow along. Those who study Culture realize that Culture changes too, but it does this very slowly and never without a bit of anguish along the way. Before now when a document stated NAD 83, we just accepted that we should use NAD 83 and I am telling you it is like this to the professionals in the field, but now you say it needs to be even more official than what you have already been instructed by the datasheet and your knowledge that the NGS does not concern itself with Other Datums than the ones it owns? The NGS has to come down on this just for you or you refuse to believe? Is that what you mean? Um, Ok. If the only official Horizontal Datum of the NGS currently are NAD 83 and NAVD 88 what more do you need to be told? If an Official NGS Datasheet says: *CURRENT SURVEY CONTROL ED0700 ___________________________________________________________________ ED0700* NAD 83(1986)- 34 52 34. (N) 083 57 31. (W) SCALED ED0700* NAVD 88 - 576.857 (meters) 1892.57 (feet) ADJUSTED ED0700 ___________________________________________________________________ From this I take it they are not asking me to substitute any other Datum here, they Officially want me to use the ones they are working with, and they Officially expect me to do this too. (and I will if I want to be right.) It simply goes without saying. Is is like common sense. There is no other current survey control no matter what the supposed accuracy or formatting. Please make note that this quoted text from an "Official Datasheet" is calling the Datum outright and implying the desired display format of D.M.S by using that convention in the first place. At this level of accuracy, there is but one Datum we should concern ourselves with, and if it is not listed on the data, then we should not concern ourselves with it. The NGS does not adjust or even work with the WGS 84 Datum and they really have no desire to. They do not even offer tools to convert back and forth to that Datum. You see? Get it? They want nothing to do with it. Not their Datum. It uses different everything than the NGS does. The only similarity is that they use the same satellites to do the work. It has always been the practice to use the Datum asked for, Not any datum we want. If I am handed Building Site Plans that ask me to survey in NAD 27 then that is what I do. They designed it that way. If the Vertical Control is in NGVD 29 then I set my control to match. When I work with NGS Data, I use the Datum they Prescribe. It is as simple as that. If someone has a problem with this standard or practice, perhaps a different hobby or even profession is in order? Maybe. This sort of thing was never needed to be written down, it was just one of those things that was always done and not questioned. Ingrained in us as surveyors just as I am trying to ingrain it to all who read this. I guess part of my career which is ingrained in me feels wrong to question this, I mean, like why would you even want to do that? Why would I knowingly want to do something to increase the factor for error. That is counter culture to me. If I could foster a perspective I would want it to be such that we work as accurately as we can from the start, By using the time tested standards we know will work well, rather than be flippant and say we can interchange Datum because they seem close enough. What may seem, is not necessarily what is, and you never know when you could buy a GPS with even more accuracy than you now have. Would you need to unlearn poor habits that didn't seem to matter in order to learn the right ones that do matter? Why not just be correct from the beginning? Does a worthy Ethic need to become an Edict in order to have the credence it should? Of course there is an official Edict but I feel the Ethic is a better motivation. If it is only a sense of authoritarianism, such as following a official rule is the only thing that someone will revere, then I suppose we will have to ask that a rule be made so that people will then be expected to follow it. But the Jails are full of people who simply love being their own people, Rules be damned, so will it help? I doubt it. We in my industry have never needed this sort of motovation, and have always respected the rules, even the unwritten ones because they are the underpinnings of integrity that makes the system as good as it is, and it is very good. It took a lot of work and a lot of respectful Surveyors to get where we are. I am not trying to be arguementative, nor am I implying that you may be either, but it seems a shame that some people would not respect the practices and standards as they are. The Devils Advocate is not a useful position to play in this. Here is the alternative. Here on geocaching the joke always seems to be on the USPSQDN for their not founds. Soon there may be a segment of snickerers out there who make light and mutter about Geocachers refusing to log corrections in the correct datum in lieu of an official rule. Is there a way we can avoid this? Sure. Hold the work you do in High esteem as you well should since you will put your initials by it. And when you do, Be proud that you followed the standards that those before you did, and you are following in the foot steps of some great, knowledgeable people who pioneered this and made it possible. You too helped make it better by following the Standards, Practices and the history of the work. Further I think anyone interested in following the Standards that the NGS would like people, including us to use would do well to familiarize themselves with the information on this page: http://www.ngs.noaa.gov/FGCS/BlueBook/ It does outline the use of Degrees, Minutes, Seconds, and Decimal Seconds as the preferred methodology, amongst many other preferred methodologies... In the field we just are not accustomed to questioning the practices as much as were are focused on trying to follow them. Perhaps you are right, Maybe it needs further instructions and more succinct rules, even if the Blue book is not enough. But lets give Casey and NGS time to work up their FAQ and such. We may be pleasantly surprised.
  8. Hi Gary, That idea you have would be very cool if only it were true... See, all the old marks were hand written and typewritten Data. elcamino, aka Z15 has some photos of the old datasheets, and maybe he will post one here as an example. Anyhow, The NGS had Files and Files of these datasheets and so the people at NGS sat down and hand entered the data into computers... there was no OCR software involved. Talk about looking up at the bottom of a big mountain with a very long hike to go. Now if there was a rhyme or reason as to how the stations were kept in the files prior to being given a PID, I have no Idea. I can tell you from my experience with the Numerical order of the PID system in the N.W Washington State area, that if you were to plot this on a map, PID for sequential PID, a lot of it might appear pretty random. Sometimes it will chase a Level line but triangulation will look like a shotgun pattern and the two major station types will intermix as well. I could never really count on sequential anything although I did observe it from time to time. So, If there seems to be a rhyme and reason, it only seems to at some times, and this is not a searchable thing, it is just happenstance. If we want related stations, we can look up the level line itself, or on Triangulation Stations with a Box Score section, we can find related data there but that is about all I can think of which will interrelate things beyond the luck of how they had been kept in the files back when. There was a lot of CGS station monumentation performed in the 30's as part of the New Deal, and that is why we see a very large body of work from that era. I suppose you could search for date specific stations and radial or rectangular searches for nearby stuff, but I fear you may have to read each one to make sense of it all if there is a link at all. In the case of ED0700, I am not sure what can be said about this. We are not sure about part of this as we are sure an error has seemingly been made. Further we have a case where either the NGS has adopted a USGS station for it's use, or the USGS submitted to the NGS for inclusion at some point in time. This could have happened during the 1930's but if it did, it will not become part of any hard and fast rule we can all use to think of PID sequences in a certain way, It will just be something that happened that way. Pure Happenstance. In any case, I am sure that you have found some erroneous information on the datasheet for this Station. My call on this one would be to email and ask Cheryl at NGS if there is more to this station apparently meets the eye. My take on it is that she may be able to sort out some things we cannot see. Other Data which is likely there but not needed for the datasheet may tell more of the tale. It may be interesting, since this was first a USGS Station to write them and see what their Data has to say, and Perhaps NGS has this information in archive as well. Sometimes they will. So you see, the sequence does not necessarily help us with dates, or any other similar data as the PID system is a part of the Computer Age and the Data ascribed to the stations does not always follow a particular hierarchy of any kind which can be logically followed. Beyond this, the best tool seems to be our own brain and our familiarity with the datasheets for the Stations in our local area. Local Knowledge makes you one of the local experts. Good Luck Gary! Rob
  9. Sorry Bicknell, This will eternally be a not found, now that the bridge has been destroyed. Here is the Why: JV3108_MARKER: DB = BENCH MARK DISK JV3108_SETTING: 36 = SET IN A MASSIVE STRUCTURE JV3108_SP_SET: BRIDGE WALL JV3108_STAMPING: V 252 1942 JV3108_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL This setting was a Bench Mark Disc. In order for NGS to Destroy a Station that was monumented as a Bench Mark disc, the actual object, the very disc itself must be returned to the NGS as physical evidence. That is their methodology... There are super rare occasions when other considerations are made but as I said, this is rare. Even if the object it was monumented upon is now gone. You are free to write Deb Brown, But I fear she will recommend a Not found filing since the actual disc was not recovered. You can list it as destroyed on Geocaching.com. Good Luck! Rob
  10. Black Dog, In My professional opinion Yes. The difference in accuracy between these modes on a GPSr is not going to matter to the surveyors as much as keeping with the conventional way they think. We as geocachers are simply trying to improve the position of a scaled location. With the equipment a geocacher has that is all you can do. I as a Surveyor use this Data on the clock to do my work in a timely, accurate manner. My equipment is capable of infinitesimal accuracy in any display mode. If I can stake a 2:1 slope ratio with a vertical soldier pile wall cut 40 feet above what will be finished building pad grade, all while keeping track of my topo for earth moving quantities as per job bid item, I can sort out the last 5-10 feet of an improvement to a scaled location. The Culture of Survey Data Annotation is in D.M.S Format and we are not going to change that 200+ year culture. We should make all data entries in the Format which is expected. If we do not, we will cause Surveyors to make errors or waste time if they do not catch what method we did. I can tell you first hand that looking for a Location in the wrong format can lead to errors of over tens to hundreds of feet. Let us avoid causing errors by not using formats that end users of the data will not expect. No one is going to change this convention. The consumer grade GPSr is not dual channel nor often DGPS capable. This sort of accuracy simply is not enough of a big deal to matter to the consumer level, as we are talking about improving a scaled location to within 10 feet. I am sure 10 feet is a lot better than hundreds eh? In that respect we have already done the Surveyor a huge favor, given them a big leg up on the hunt. That is worthwhile and good to smile about. I can tell you that I for one am grateful for the improvement of the To Find. So let us accept that this is the best we can do with our consumer grade gear. Please remember, we Surveyors are not going to perform Horizontal Surveys from a Bench Mark. This is simply to aid the To Find accuracy and that is all. These are Vertical control Stations. When I am looking, and if I am looking with GPS I am looking in D.M.S Mode... Always. We are not going to change the way Surveyors and Engineers think and it is not helpful to add one more thing for them to remember. I am one of these people and I know my brethren well. If they read your D.MM entry and follow their training and conventions of working in the D.M.S formats as they are required to do by every municipality or other agency around , this little conversion will throw them off by hundreds of feet if they overlook it, and they will overlook it. When we do this to the Data, we are asking them to convert for you, the Geocacher, when in reality, we should be doing the conversion for them. They are the prime end users of the NGS Data. The Surveyors are the Customers and Clients of the NGS and that is the Customer service they provide the users of their database... I did not miss your recommendation, but more importantly you left the premise of what you felt was an unanswered Question, and I very much wanted you to have the answer to that Question. I also had a sense from how you prefaced things that you felt your unanswered question held higher importance than the recommendation you made. We surveyors do not really want to see 40 different ways of convening on the where of a Bench Mark, we want the one we have been using for 200 years... When the Surveyors try to answer these questions for you here in the forum as you pose them, Please trust our experience. We don't know everything but we are doing our best to give you the best information we have. Thanks, Rob
  11. Harry, When you scale a location so as to give it a Latitude and Longitude for future purposes it it done with a Map and a ruler. You could do this too. Take out any USGS Quad map and lay it on the desk. Orient the map to the North = up position. Pretend any BM on the map it the one you want to know the coordinates for and scale it. It may be best if you know that the USGS BM on the Map actually exists today because then you can test your work. Take a ruler and see if you can determine the scale on the map for the ruler you have, If you happen to have a ruler in engineers scale, all the better. Lay your ruler out perpendicular to the grids on the map, starting with the horizontal and go over to the left edge of the map at the margin. Make a light pencil mark there and repeat this process for the vertical... Now using those two light marks you made, do your best to ascertain the Latitude and Longitude of the BM you are scaling on the map. Take your time and squint hard, because at best this will be a guestimation. At these scales, even a pencil line's thickness can resemble many, many feet of difference. Now you have scaled the BM as best you could and recorded your findings. You have just done what all the leveling crews did to horizontally locate their stations after setting them in place. what's more they are scaling a station that is not already located on a map, they are trying to project it's position onto the map from nothing other than a best guess of where they are. Now if you like, hop in the car and drive out to where it is with your GPS and find it. Compare the difference between your scaled location and what the GPSr actually gives for coordinates... You may do better or worse depending on how many minute quad you have and how well you can guess these things between tick marks on the map, but this is the very thing we are up against on a scaled location, and now you know how the data was determined. Good luck and enjoy, Rob
  12. Arkville, If you think this BM is soon to be destroyed due to the demolition of this bridge, the procedure to use, should you want to make someone who has the official capacity to keep an eye on it would be to contact the State Geodetic Advisor for the State in Question. Anyone can do this in any State By the way, and the links to do so are on the NGS Home page. Since this station is in the State of New York, and New York has no assigned Geodetic Advisor, The procedure is to contact: Mr. Gilbert Mitchell National Geodetic Survey, N/NGS1 Telephone: 301-713-3228 gilbert.mitchell@noaa.gov You are under no obligation to contact him, but since you asked, that would be what one could do, if they were to choose to do so. He will know how to handle this and make what ever choices which will need made regarding the future loss of this station. That is the procedure. Should he not be informed, the Station may wind up as rubble and lost forever. Then the next time someone searches for it and does not find it, they could enter a change in status for this station in the database from a Good to a Not Found. It would then become a Not Found in the NGS Database until the end of time. The Numbers as Matt pointed out were at one time the elevation for the station. The practice of doing this is no longer in effect and all Elevations stamped or etched into surfaces near BM's are considered to be in error. The methods for deriving accurate elevations did change and it caused all the old numbers to become inaccurate. Currently the only accurate method and accepted practice of obtaining elevation data is through a station's datasheet. Good luck Hunting! Rob
  13. Blackdog, I think I have tried to answer your question on more than one occasion, but I will try to do so again. You Asked: "The question remains - what format should we be using when entering coordinates to the NGS?" This Question does not really remain, as it really doesn't need to be a question, and hopefully I can explain why. The NGS is a subdivision Department of the Department of Commerce. They control all the Civil Geodetic Data in the United States and set the standard for all of North America, Including the countries of Canada, Mexico, and has also been extended to the Caribbean. They are the Creators and Owners of the NAD 83 and NAVD 88 Datums, and continue to further the science of geodesy with the best people they can find, working on new methods all the time. This is their Standard and it is up to the users of their standard to follow it if they use it. When we use a system, we accept that we also use that systems set of Standards and Practices. Many, Many Books are written about Standards and Practices, By the Feds, Each and every state, Many Municipalities... And we as Surveyors, (and anyone else) have to follow them. It is just the way the game is played. When a Practice seems to be in place as a standard, yet does not seem to be expressly permitted, advocated, or forbidden, it is good form to follow the practice or someone will be along to write a rule governing the Practice in question shortly. It is kinda like Murphy's law in that respect. The correlation to the Law is always something that will make things more painful to use, I assure you! That is just the nature of this sort of thing. :-) They (NGS) set a Standard and the hope is that all People, Agencies, Municipalities, what have you, will enjoy the high accuracy, and so to make this a repeatable experience, we all adhere to the methods set forth. Many of these standards are historical and Age-Old. D.M.S is a format that has been used for most all Surveying all the way back to the early days of this countries history, likely much of the history of Survey. Perhaps the practices of the Sumerians, and of course we see the higher accuracy of this format by the number of places the number is carried to the right of the decimal. It is designed around the way a Transit, Theodolite or in today's world a Total Station divides up a 360 degree circle. We don't see if we can introduce errors to it by using different methods, we use the one that makes most sense, as all the old instrument divided a circle in this way, and the Math was done with a paper and pencil. It was not good practice nor exactly easy or timely to play with alternative conventions until quite recently. In fact it was not long ago that if you were on a survey crew and suggested this, or an idea as such, the party chief and some of the others would likely look over the top of their glasses at the mention of your idea, and it could be a couple weeks before they talk to you much, or again. Yup, It was Old School, and in some places and ways, it hasn't changed much. All the Data is output in the format they have always used, and it stands to reason that it should continued. These numbers are not about how close they are with a $350 GPSr, they are about how close they are with a $10,000 RTK GPS. At best in any format, a GPSr can give a circle of 5 foot accuracy. Remember, all we are trying to do is physically find the Vertical control and improve it's scaled location with a GPSr. If we want this improvement to have credibility, we need to adhere to the standards being used. There is a bigger danger for error being introduced by using the alternative formats that we might think, and though it appears we think we can test this, but it really is more of a happenstance. As an example, Recently, I think I read where there was some confusion over inputing data to the mark recovery page at the NGS site... Somebody used the back button but forgot to correct all the fields for entry to the proper *new* PID for submittal and so they wound up writing Deb to correct this human error. I think it is very cool that we all try to be this conscientious and get our errors repaired. I am sure it has occurred to more than one regular here at the Forums. But this human factor is the purpose of my point. In the same Fashion, this is why I would like to encourage everyone to just accept the practice of using the NGS standard for D.M.S format when dealing with updates to the datasheet. We may think there is little difference in accuracy, but the crippling factor is when mistakes get made, You know, the Human errors, and they will get made. The Three formats all output a different number. When matched to the correct output format each describes the same place. But, and a Big But, if we mix our metaphors, or output formats with our data we can quickly inaccurize the result by mistakenly calling a D.MM number a D.M.S number, and I have seen this happen more than once in my career. This mistake will foul the actual location value up by Hundreds of feet, and all by a very innocent mistake. I have personally, and professionally hunted D.MM waypoints in D.M.S and they are not findable by that method. My mistake was not realizing that the person before me had not followed the standard practice, and when I changed formats I walked right to it. The important thing to note is that I should not have had to worry about such practices if the person before me had followed the standard. Things that make you go Hmmmm are well, not always a good thing... Just like Arsenio Hall and Martha Stewart on a date, if you could imagine... Uh, well, or don't :-) We don't want to go there... What I said is if we submit a Number output in D.MM and mistakenly call it D.M.S Number, or visa-versa, or juxtaposition by mistake, the result will now be inaccurate by hundreds of feet. This is not good, and not only can it happen, it does, happen by just adding a D.MM number to a datasheet without saying which format you used. ** All Professional users of the NGS Datasheet will be assuming the D.M.S Format and field conversions are not what they want to have to do to make it work for them. ** That reason alone is the best reason to stick with the D.M.S Format if there are no others. Soon we find our selves asking did I do that right? as we were back and forth between so many formats... I realize that not all GPSr units over time have not been created equal, and we all have the one we have. Good bad or indifferent, it is always considered a good practice, or good form if you will, to stick with the formats being used, or as someone recently pointed out, When in Rome. If we always stick to the standard practices and always do it the same way, we get into good habits which never have us wondering what we did or if others will be able to figure out our work. This is also why we surveyors can figure out the work of other Surveyors. We stick to the practices which are the accepted norms so others can duplicate our results. We can of course choose instead to be independent and do it our way, but we might not be seen as helpful by everyone concerned if we do. It is cool and informational to know, concerning the ways the GPSr seems to handle this information in the different formats, and it may be cool to write the manufacturer and see how they test all this as they develop their own Specs, for each brand and type of unit. If they are using a Parts Per Million method of determining accuracy, it is likely that the accuracy is the same in all formats, yet changed by the way the format may truncate the data output to the screen. I hope this helps you understand, but if you like, you can write Casey, Dave, or the NGS and see how they come down on this. I perceive that all their datasheet output formats already tell the tail. In any case you are correct, this new position is usually better than a scaled position any day! Rob
  14. Reading the description is very important. It is also important to remember that the NGS is dealing with the desire to keep things as accurate as possible, and to improve on that as possible. They have very rigid, rigorous standards and for a very good reason. They have to with the kind of accuracy they have achieved. They allow us to submit information to be added to the narrative section on a datasheet and a pair of eyes does look at our submission before it becomes a permanent part of the datasheet. Adding the waypoint will suffice, and perhaps the NGS may choose to change the scaled info to the waypoint, but I doubt it... It is way safer to leave the scaled waypoint, and allow you to update that with a waypoint in the narrative. This way the back up data remains intact and on the datasheet. It is a form of a paper trail of events, and we have all learned that knowing any given station's individual history is important. All the Data may dovetail with other data we are not privy to as well. We have to leave all the clues in tact! :-)
  15. Artman, You are correct, they often do straddle and without physically going out to see for sure, especially the scaled marks, it is just a judgment call... It is possible with scaled marks to have them scaled and properly located in one county, yet when physically found, located in another. If we find this situation I suppose we should write the NGS with our ACTUAL Waypoint of the found Scaled station and see if they would like to make a correction for the county. I suppose the user of any stations may be well advised to investigate adjacent counties for their search, or better yet, do a radial search as an alternative. In the end, the best we can do is the best we can do, given what we have to sort it all out. I'd say we are doing well! Rob
  16. The issue that is most important is that if the entire county is pulled from the NGS website, that all the Stations in that county be searchable from that county. If they are listed in the wrong county then they can't be searched as they should. Though it is sketchy on some Scaled marks, if it looks to be that the scaled station is in the wrong county, they are more than happy to double check it and move it if they think so too. It is a sort of end user orientation. The people needing the entire county could actually determine something else upon physical investigation, but it is best to give it to the county it appears to be in, data wise, if the station seems to fall within the boundary. It is likely that no one has ever looked at this situation in the way we have started to, and so it is putting right a lot of borderline examples like the ones you listed. They are getting looked at for this reason alone, and it is a good thing. There are times that insisting corrections be made only on adjusted stations is wise, but this is a judgment call situation. We look and make determinations based on what we think we see, and forward it in. They look and change it if they concur or not... At least it gets several sets of eyes on it and that is a good thing. Rob
  17. Blackdog, I like the way you are thinking. Like I have said in more than one previous post. Since these Monuments are part of the very basis of the NAD 83 Datum, Uh, Why would we want to use any other Datum? Since NGS Style Benchmark Hunting is basically about Very High Technical Accuracy, It Goes without saying. It also goes without saying that even though Geocaches are in the WGS 84 Datum, NAD 83 is close enough to use to hunt a Geocache, Because the Technical accuracy doesn't really matter. Geocaching.com likely realized something early on and was simply trying to keep things simple. Fresh out of the Box, a GPSr is defaulted to the WGS 84 Datum and the display is set to Decimal Minute Format. I would imagine they did not want people to have to become more technical than necessary in order to geocache so they set the game up around those parameters. After all technical things are not fun for most people, just some of us seem to enjoy this. Later entered Benchmark hunting, the same theories were applied to the database, and then we as benchmark hunters evolved. Now we have come to understand that this case of trying to keep it simple is not always in our best interest, and could be made worse if GPSr manufacturers ever allow us to have more accuracy than we currently have in our handhelds. I concur, Set to NAD 83 and forget it. It is good enough to Geocache with and best for the serious benchmark hunter. Lobbying Geocaching to alter the format back to degrees minutes and seconds is well worth consideration but I wouldn't expect to see them change it. It may be a choice of accuracy over simplicity for us, however those who want to benchmark hunt seriously can easily make the necessary changes. The folks who just want to play may see it as too much bother and not enough fun. For those who may want to know more about the display format interaction, here is the formulaic method for converting display formats (longhand method): http://life.csu.edu.au/geo/dms.html Rob
  18. I'd keep knocking at the door, evenings, weekends... Look them in the eye, shake their hand, explain with NGS documentation what you would like to do. Many States do not even have provisions for protecting a Surveyor from trespassing on private property and some people can and will make a very very big deal out of it. I'd be careful. Face to face is really the best way as many people will want to see you and size you up. Permission is always the best thing to have on private property. Posted or not. If you don't get permission or are told no, it is probably best to just skip it... Good Luck! Rob
  19. Bicknell, The observable difference is this. The consumer grade GPS units are no more accurate than 5 feet. if you are within five feet of where you need to be, the GPSr will tell you that you are on the spot. The Pro Grade Gear I use in my work will survey to the Millimeter, Actually smaller than that, but the millimeter is something we can all imagine. And a millimeter is a very - very small spot. The GPSr cannot even resolve a number this small so you would never see the accuracy. Now if you were to imagine Two Datums, call them NAD 83 and WGS 84 then picture a computer image of two transparent, earth sized spheres that you can see a dot for the sphere center (earth center) inside of each, and we could see the translucent surfaces. If you could walk into the computer image and were to take a tape measure and hook it to the sphere center point of the NAD 83 sphere, and pull it to the sphere center point of the WGS 84 Datum sphere you would measure a distance of one meter separation. Now this is not the whole problem solved. Pretend we have a frame of reference for these two spheres which is separate from the Datum them selves that allows us to compare them. Say it is a Plane reference where we know know where level and Plumb are. we call this frame of reference the ellipsiodal height. There is a paper on this you can read here that will sort of explain in great detail some of the concept I am trying to simplify... well sort of, and the main thing is to just get the gist of the idea here, not become a geodesist unless you want to be one... Here: http://www.ngs.noaa.gov/PUBS_LIB/gislis96.html Just remember that in this explanation, we are also thinking beyond the scope of that paper... There is probably a better one too but this will work. Anyhow, When we compare these two spheres as being inside one another we find that they are not level on a horizontal plane nor Plumb on a vertical one, and so a Cartesian Coordinate way of thinking has to be applied here, because when we actually compare the datum, we do so on the surface of the Sphere. So on the surface of the sphere if it were a perfect sphere there would seem to be a few, (4) places of note. Two places where we are at an extreme one meter apart, and at a right angle to those places, 2 where we should Null and both Datum would read the same coordinate. But this never happens. Why? Because WGS 84 and NAD 83 Not only use different earth center models which cause the datum shift in the first place, but they also use different versions of geoid models which further skew the result. One other thing happens. The earth is Not a perfect Sphere, it is actually ellipsoidal and the surface of it undulates and is not smooth, this is partly why they coined the term Geoid to describe the surface of the earth... Remember there is Death Valley, Mt Everest and everywhere in between... It is conceivable and correct that there are places , many places on the surface of the compared spheres and the earth as well where the difference is somewhere less than a meter, and comparatively run the gamut from zero difference to the full meter, but to compare them in not just a straight line comparison. To see it we need the Cartesian thinking. This is a three dimensional set of Spheres. If from our frame of reference the WGS 84 Sphere was up and to the right of the NAD 83 sphere, then all the errors would be Up and to the right and we would then have to figure the differences between how much up on the vertical and how much to the right on the Horizontal to calc the coordinate. It is conceivable that in any given place a comparison of the Datum could be horizontally off by a foot, but in the same spot, vertically off by 2 feet yet the Hypotenuse, which is the straight line between the 2 points being compared would be less than one meter. You can observe how this works with Pythagorus' Theorem: http://www.ilovemaths.com/2pythagoras.htm Most importantly here is that we know this, but we never bother to do these comparisons. We Know this happens and don't want it to, and we avoid this because we stay in the datum we need to. We don't intermix the Datums because this introduction of errors is what will happen and we don't want to compare it, we want to avoid it! This sort of skewing is a very bad thing for accuracy in our business. And this is why we stay in the Datum we are asked to. I guess I am asking you to trust in some things that you cannot see with your equipment but they are there... really! Rob
  20. To add to elcamino's list of answers, Some Cities, Counties, And Specific Projects (still) require us to Survey in NAD 27 and or do all the Vertical work in NGVD 29 even though they are both no longer officially supported. They will refuse any survey from newer datum and refuse to certify it. If that is what the local rules are, even if we think they are antiquated, it is what we use. It is a both a political and economic decision on the part of some areas, They have not the funding to properly convert, Or the powers that be are old school thinkers and refuse to move along with the progress of the world... It happens. And so we set the equipment accordingly. It does highlight how important being in the correct Datum is however... One thing that is nice, and a feature of any GPSr, is that there are many Datum already loaded into it, and you can easily toggle between them. If you were to make waypoints in six different Datum as you went, you would see them all in your waypoint list, but they would all display in the Datum you currently have the GPSr Set for. In other words, Automatic conversion. You don't have to go back out and re accomplish the waypoint, just change the Datum setting in your GPSr from WGS 84, or what have you, to NAD 83 and all the waypoints automatically convert. They all now are being displayed in NAD 83 if that is the setting you chose. If you no longer have the Coordinates in your GPS it may be too late, but on the off chance you may need to convert some numbers back and forth between NAD 27 and NAD 83, the NGS Geodetic tool Kit Has this offering: http://www.ngs.noaa.gov/TOOLS/Nadcon/Nadcon.shtml Rob
  21. A cheap Clinometer can be made by a quick trip to the office supply store and the Hardware store. A cheap plastic torpedo level can be had for a couple bucks, and then a half circle plastic protractor is pretty cheap and cheaper at a place that sells common school supplies like the grocery store. There may even be places where you can buy both. Just take the protractor and with a sharpie marker, make a black mark at the 15 degree mark on both sides so it will become easier to see against different backdrops. Hold up the Torpedo level before your eyes and level it with the protractor held level with it and have a look around, Use your peripheral vision, you will get a feel for 15 degrees real easy. I have used the Sunto Clinometer Dave mentioned, and all I can say is if you covet fine tools, and the cost doesn't bother you, it is a sweet unit. Using it will bring a lot of Joy. The big deal about 15 degrees is that the lower in the sky, or closer to the horizon the satellites are, the more wide spread they will be and the higher quality the radio triangulation will take place. If the birds are all directly overhead, the angles measured will be acute and without the separation, the quality will be lower and take longer to derive.
  22. Artman, The Landmark stations were optically intersected, they were never occupied and are not considered occupiable. The are just low order optical triangulation. You could consider them a helper station. The used them as swing points for establishing 3rd order triangulation in low areas where towers were not feasible or timely. 4 observations will get you third order Horizontal and a landmark could be seen from many different locations surrounding it. They served that purpose. They are not suitable for GPS observations because there is no way to perform an instrument set up on them, So Landmarks that are intersected points are a NO. They are not suitable for GPS Observations. Further for the safety of all concerned, The ground is a safe place to be. Climbing on these landmarks is probably not a real safe thing to attempt. The NGS did the Washington Monument because they could. The scaffolding was already in place for another purpose, and since the last time they had scaffolding on it an instrument was set up, they wanted to compare the numbers... Mostly because they were afforded the opportunity, and for the adventure of it. Rob
  23. Marty, The important thing about Survey marks, and all surveyors know this, is that if we do not have the data for any given marker we see in the field, we simply are not concerned with it. Period. It is simply not on our radar. If we are handed data for a new station, then we become concerned. I mean we deal with hundreds of stations of Many Many types every month. When I am Chasing PLSS I have the data for it and the Data has recorded in it what I am looking for and where I should find it, so a Disc that says GPS Fun on it will be of no concern to be should I cross paths with it. I know it is a marker but it rates so what status because it is not on my radar, and it will not confuse me nor be misconstrue. PLSS work on someone's yard is not a big deal, even if it has no markers left from the last time it was surveyed. I just have to work backwards until I get to known locations which still exist and have not been seemingly disturbed... Then I work forward, with the measurements and angles I am given in the "formula" (if you will) for reaccomplishing the lines and corners... PLSS is not going to contain Vertical Data so I am not even concerned about something called a Benchmark... I mean it isn't a BM or a Bench Mark... Two words, not one. In other words we have ways to piece it together. If the survey does not contain the words Do something at the GPS Fun Marker, that I am not considering that station as part of the work I am doing. All this stuff is recorded at each county seat and is age old. Every change and all... The GPS fun Station is pretty clear about it's use right on the Disc... It is no big deal... The Word Fun is not work eh? No Surveyor will be concerned nor care, as it is no different to me than some other Surveyor's Pink Flagging tied in a tree. It is not my stuff. There are already tons of firms with monuments in the field, what is a few more? Try thinking of it this way. I stopped at 100 when I was looking at Land Surveyors in the Phonebook, so what would one more make? I mean what if a new licensee hangs out a shingle tomorrow? It won't upset the balance a bit. They all have markers set out there somewhere that are unique to them and, along the same lines the GPS Fun Disc does say how to obtain info about the Monument so they are playing the game as well as the rest. Any surveyor could go back to the office and get on the net to see what it is... It seems I have defended GPS Fun more than once. But really it is about fun and they are forthcoming with their info... It is just another Monument... Not unlike yet another Geo Metro... Or another Cell Phone... I think they have been up front about what they are doing from the Name of their Organization On... It is all about GPS Fun! And well, GPS is Fun! I am not dissing Geocaching at all, but think. Geocaching is Fun and it is GPS oriented, yet some Cachers abandon their Caches and they just become trash, Litter. These Monuments are buried in the ground and most people want them in their yard. They are wanted, and even if they become unwanted, they are not going to be blown by the wind or become a form of litter in the environment... Pretty low maintenance and impact I'd say, you can even mow the grass without disturbing them! Heheheh, I think they will be fine! Rob
  24. Ok, there are a few animosities here, Let me see if I can help. I have covered some of this ground before but it is worth going over again. Part One. First WGS 84... Some people feel that WGS 84 and NAD 83 interchange. They don't. There are times when horse shoes and hand grenade theories are doable, but really, this is not one of those. The important thing is knowing when is which. There is a difference between the two Datum of about 1 meter because they both use a different mathematical model for the earth center. After all, We are helping to update a database which is the National Spatial Reference System, and it is serious minded important work. It deserves being held in our highest esteem. We should treat it with care. WGS 84 will get you there but when we work and affect changes to the NAD 83 Database, we should use NAD 83. Further, if Handheld GPS units were to become more accurate, this difference would easily become revealed. The GPSr is giving you at best a 5 foot circle of accuracy, and if you are using WGS 84 you could be adding more inaccuracy. In my Professional work, have DGPS instrumentation that I can walk with in my hand that is accurate to a 1/100th of a foot while I am walking around. In other words, Pro Gear reveals this difference. What I am saying is this. NAD 83 is a Datum. The North American Datum of 1983 is the official name. It was developed by the NGS. These Stations which we call benchmarks here at geocaching are part and parcel the physical references for the NAD 83 Datum. For the sake of argument, you cannot separate these monuments from NAD 83 because they are NAD 83, (and NAVD 88) so, if you use a different datum to describe where they are, you inaccurize them, because the professional is using very accurate equipment. It is easy enough to set the GPSr to NAD 83 as opposed to the WGS 84 Datum and it will convert all your waypoints to NAD 83 For you while you are toggled to that mode. Then when you want to Geocache, you can go back to WGS 84, or you could just leave it at NAD 83 as that will be close enough for a geocache. Now as geocachers with consumer grade equipment, it is hard to see the accuracy, I know this too because when I am with my GPSr I find myself wanting very much to be able to see inside the 5 foot circle of accuracy. Our GPSr does not reveal it, but it is there. The NAD 83 is "Adjusted" because there are CORS Stations, Constantly Operating Reference Station, which along with other stations track the surface of the earth all the time, it is not just a snap shot, The NGS can look at any of them over time, all day every day monitoring and note changes, (read watch the earth move) and guess what? They change! Another reason why they readjust is because the see the changes and the run least squares again, Guess what? New results! Then the Geodesists don't help matters by creating new Geoid models based on Mathematics and testing, further observations of the world, and in our case, the North American Continent and each State and Counties or Cities, even Countries which participate... In Summary, Gravity is found to not be stable throughout the earth's surface, and this causes minute or bigger changes to terrain. Math is becoming more inclusive of the variables, some are newfound variables as well. New theories come to light, and we can never ever just leave things alone! What fun would that be? We have found things are not ever static. Adjustments never stop. WGS 84 is a different Datum, Created by different geodesists at a different agency for a different purpose. It accounts for the Vertical and Horizontal all at once, yet is not super highly accurized to the millimeter like the NAD 83 Datum is on the Horizontal, nor like NAVD 88 is on the Vertical. (NAD 83 can do both Vertical and Horizontal as well but is only accurized Horizontally. Vertical Control in North America is handled by the NAVD 88 Datum.) WGS 84 is maintained by the Department of Defense and they do not adjust for small anomalies on the North American Continent, They just put a Datum out for the world and allow other countries to use it and perform their own local adjustments, A lot of Europe and Asia does this. We don't. The US Department of Commerce Heads up the NGS and they do it for here. This is not to say the Military cannot find it's way around North America, It can, but not likely to the millimeter. Tanks and Bombers do not need millimeter accuracy. Centimeters are close enough. This is also not to say that the NAD 83 Piggy backs on or is related to WGS 84 in any way. It isn't. Part Two... What does "Adjusted" really mean when we look at a datasheet. Well, where to start? Ok, lets keep in mind that on any random sample of a group of PID's there could be both Horizontal and Vertical control involved. But I would like to recommend that we not think of them this way, because It is possible, even though I am being completely hypothetical, that PID ZZ 1234, ZZ 1235, ZZ 1236, and ZZ 1237 could be A, all Bench Marks, B, All Optical Triangulation and a mix of any order, C, all GPS derived A or B order, D, All CORS or some derivative thereof, Or E a mixture of Any of the above and you could find this to hold true in any random sample. The PID has no bearing on what kind of data the station has. It is just a form of dewey decimal system of sorts... A way to catalog it all. So since we have to think of each station specifically, Lets. The Hypothetical, randomly assigned PID, ZZ 1234 just happens to be, say, a Bench Mark, and what this obviously means to most who understand the terminology, is that this data is for Vertical control. It has been carefully measured to within better than 3 inches of accuracy and is likely more accurate than one half inch, On the Vertical Only. ( I routinely level to 1/100th of a foot) But where is it? We do not think of where we are Vertically, we think of where we are Horizontally. Well, when Bench Marks are Surveyed in, in a process that was called Vertical Leveling back when it was all done optically, Uually, but not always no horizontal work was done. (Some stations got both treatments at different times, and it was usually triangulation that got both. First triangulation and leveling if a Level line happened to be passing by. I have seen leveled RM's as well...) The "where" was not established by a Survey, no angles were turned, so the where was determined by pulling out an USGS Topo or something similar (NGS Had their own inter-agency maps too) and the location was SCALED by using the Scale on a Ruler aligned to the scale on the map and so it goes... It was meant to get you close, and the narrative description would home you in from there. The basis for doing this was to simply locate the station so others could find it. Enter today. The GPS era where we can know where we are with 5 foot accuracy. It is like Compact Discs that digitally reveal the flaws of the old Analog tapes used to record things in bygone eras... We commonly reveal the sad truth that scaled positions are not as accurate as we would like. Here are a few fairly hard fast rules that you should be able to count on in most cases. If you pull a PID from the database and see the location is "Scaled", You can pretty much bet it is a Bench Mark Station which has never been GPS'd or Triangulated optically, as so to have both types of data. If the location is Adjusted, then there is Horizontal Survey Data ascribed to the station and it is highly accurate to a degree which a Consumer Grade GPS cannot reveal. I am not saying you cannot find errors. We all have. If you are looking at the station and the stamping says you have found it, you are set to NAD 83 and the GPSr Coordinate does not match an Adjusted coordinate to the degree with which it is able, you may have found an error. Doing an Adjustment of Stations of Scaled and Adjusted Types together is impossible as they are totally different. The Scaled Station is Scaled for Horizontal location but the actual Data is for Vertical purposes, so the Least squares adjustment is in the vertical, not the Horizontal. Even the Datum is different. NAD 83 does not adjust for the Vertical. The Vertical realm is all NAVD 88. Conversely the Least Squares on adjusted marks is all Horizontal Survey and since the location of all vertical stations is not part of the NAD 83 Datum, they do not become part of the adjustment. If there are any further questions about the come and go of all this, Please feel free to ask. It can be a confusing subject! In Edit, I want to add this point. I have been reading a lot lately where people are finding the coordinates off by many feet. It is not a bad thing, and we are not finding grievous errors here. The Meaningful data on those stations is in the Vertical not the Horizontal. But we can improve it. This is just a scaled vertical control station and they will never be found as adjusted unless they were GPS'd or optically Triangulated, and almost always be off. We can make an effort to hunt vertical control and add our found NAD 83 Waypoints to the database Narrative to improve this, if it is not a GPS Station. GPS will be A or B order Vertical Control. In GPS land the Horizontal Location will be to the millimeter. Optical Horizontal Control will always be Adjusted and more accurate than a GPSr can reveal. I covered a way we can format this for the narrative earlier in this thread but this should give us all a look at a way we can format the addition to the data for the narrative as a for instance: WAAS CORRECTED NAD 83 GPS COORDINATES: 47 40 59.3(N) 122 23 11.7(W) Remember to use NAD 83! I Hope this helps! Rob
  25. Marty, There is literally tons of survey in the field and much of it only matters to the companies that placed it or had it placed. Beings this is so, you and I both probably drive past hundreds of survey stations of various types every day and we hardly notice. Like the stations we hunt here, the data for those is recorded in various ways and they are placed for various reasons, so if a game company places a bunch of marks across the country, how is it any different than having yet another survey company in town doing it? And further, no one will know what they mean unless they have the data, just like all the rest of the survey markers in the country. They will make no impact at all... No more than a manhole cover does and no one cares about those either. I am a surveyor, If I saw one in the field, I would not have the data for it with me and I would move on. Even an NGS Bench Mark is useless to me without the datasheet that corresponds to the station, yet the design keeps the placeholder out of most peoples way. I sat at a park one day and watched people parallel park next to 2 NGS RM's which were in drill holes in the top of the curbs. They were stepped on and over, yet no one even noticed or cared... Monumented in 1940, they are still in fine shape, no biggie... The gps fun folks have a similar design and it will be just another mark... another of many, many... And we don't notice most of them now... Rob
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