survey tech

Exactly, if you live in a recently developed area, you may have to travel quite some distance to have a good rate of success, 50% or so is about the best one can expect.

Azimuths can be measured from a reference line either to the north or to the south in a clockwise direction. At different times and places both methods have been used. In the northern hemishpere, land surveyors prefer north azimuths and geodetic surveyors prefer south azimuths. In the southern hemisphere the opposite is the case. Its easy to tell by checking the latitude of the stations involved. If the data says the azimuth from station A to station B is 300 degrees for example, and the latitude of B is greater than A, then B is 60 degrees west of north, or if the latitude of B is less than A then B is 60 degrees east of south.

Greg Assuming normal circumstances, the only compensation you really need to consider to use a good compass for geodetic directions is the correction for magnetic declination. There are a lot of good articles on the subject available on the internet. Heres one for example. http://www.geography.wisc.edu/sco/maps/magneticdeclination.html

Recovery is inherently confusing and was a particularly poor choice of words by the NGS. I suppose whoever came up with it was operating on the assumption that everyone involved understands that the markers are permanent and therefore would never even imagine moving one. The words removed or reclaimed are, or should be, used to denote a marker that has been rendered useless and taken away.

Thats right, the statement about magnets in the article is an oversimplification, intended to convey a general idea of what the future holds, without getting into all the technicalities. The truth is that if our technology continues to progress at its current rate, GPS will eventually become the standard means of measuring, identifying, monitoring and controlling everything, great and small, on the surface of the earth.

The ones knocked out by local workers were probably replaced nearby. In fact, there are almost certainly a lot more markers now in any given town that has experienced development than there were when the NGS database was created. The local surveyors and engineers rarely see any need to submit there work for inclusion in a national database, since only local parties would ever be likely to need to know about them anyway. Remember, the NGS work was merely a skeleton, your local professionals have put the meat on the bones over the past several decades.

I think nearly all of them have been dismantled, most long ago. The only one I ever saw was in the mountains east of Las Vegas NV, and I have been through all the lower 48.

If the description called for a disk and you found and X, then its just a coincidence that its in the same location. An X is a very common type of mark, frequently made by local surveyors. In fact, if you serarch closely, you wlll probably find an X somewhere on virtually every bridge or major culvert, particularly those at or near road intersections. Its also not uncommon to find some kind of marker at or near the location where an NGS marker once was, since the NGS surveyors generally chose their locations very well, and subsequent surveyors have set what amount to undocumented replacements for the lost original at the most useful spots, such as the one you describe. Still, the fact that its in the same vicinity does not mean that it is historically connected to the original in any way, and usually they are not.

You may want to consider getting a Suunto (Finnish) compass, of the look-through type. They are made with many kinds of graduations, some of which are incremented in degrees of azimuth, which makes getting a good direction much easier than it is using the traditional boy scout type compass.

Good job, sounds like you did everything exactly right and in a very professional manner. I hope everyone follows your example.

I thought you already knew about that, BD. I remember mentioning it at least once. By the way, the azimuths are astronomic so they will not be changing appreciably in our lifetime. Remember also however, that some azimuths are measured clockwise from north and some clockwise from south, so you can get completely turned around if you do not check the relative latitude of the station you are at compared to at least one nearby station to verify which way they are referenced in your area.

Thats right, its just an early design. Many designs were tried and some used for many years, so I could not say exactly how old it is.

If you really want to go hunting with GPS only and skip the descriptions, you need to distinguish between horizontal control points, all of which have precise coordinates, whether they were set using GPS or not, and vertical control points, all of which will be off by widely varying amounts because their coordinates were never intended to be precise. Since there are more verticals than horizontals, you will probably soon find that you have to travel a considerable distance to find new horizontals to look for.

Under normal circumstances, just walking up and asking them about it should be fine. Many people are not aware of markers on their property, so they would need an explanation, and some will be skeptical and suspicious even then. If there is any reason to suspect that the owner might be upset about being approached face to face, a letter would be appropriate. Once they fully understand the real nature of the markers, most people are proud to have one on their property, and I have met several who are even anxious to show them to anybody who is interested.

Dalton The answer to your original question is no, a legal description of the kind you recited cannot be converted to coordinates without more detailed information than you have listed. Descriptions of that kind are not intended to relate the property to latitude and longitude. Still, the place should be fairly easy to find, unless its way out in the middle of a large forest, way back in the mountains, or somwhere else thats a long way from the nearest road. I would go to the county tax assessors office, hand the descriptions you have to them, and ask to see the maps they have showing those areas. The maps are free for the public to examine and copies are usually only a dollar or two each. These maps show property lines and roads, which should make it easy for you. USGS topographic maps, usually available from sporting goods stores for the local area, often show section lines and section numbers in red, so they can also be used for this purpose, but the disadvantage of them is that most roads are not identified by name on them, making it easy for those not experienced with them to get lost when venturing into unfamiliar areas. Also, be careful not to wander onto private property and get yourself torn up by their dogs or shot for trespassing.

The answer to that question really depends entirely upon the specific circumstances. In some cases, where construction is going on, or is anticipated in the area, it may be a good idea to call attention to the marker to avoid its being knocked out accidentally. In other cases, where a marker has survived for many years in quiet obscurity, it may well be best not to call any attention to it, since it may become an object of local curiosity and a target for vandals. Generally, I would recommend the policy of leaving it just as it was.

Its a very close facsimile of an NGS disk, but it appears to belong to a local network. Technically, it is a triangulation station, not a benchmark, but a very important point all the same.

The underground mark is typical, particularly for first order triangulation stations, which would be very difficult to precisely reset otherwise if the surface mark is damaged. If someone comes careening down the road and runs off the road and hits it, which happens surprisingly often on rural highways where people drive like The Dukes Of Hazard, the surface mark is ruined, but the subsurface mark would remain. The last part about the ASHD ROW marker is strange, since no data is provided for this marker, I suspect they intended to use it as an azimuth mark but never did.

The original North American Datum base station, Meades Ranch, was seriously damaged or destroyed long ago and reset as KG0640, which may or may not still employ the original disk set in 1891. The original azimuth mark, Waldo, KG0648, survived somewhat longer but may now be gone also and has never been reset according to the record. You can read about the history and evolution of the North Anmerican Datum at the NGS website. The special significance these points once had ended when the entire network was readjusted in 1983 to a more advanced spheroidal model of the earth.

Walking along a major arterial street in a typical city, you are probably passing within a few feet of a benchmark at an average rate of at least one per block, though most are not documented in such a way as to be readily available to the public. Most are at intersections, for maximum visibility in multiple directions, in or near sidewalks, for convenience and safety. Most are established by agencies or companies in the transportation, communication and utility industries to support their own projects and are shared with others at their discretion. Some are willing to allow public access to their information, others are unwilling or reluctant to provide it to anyone, even surveyors, primarily due to economic and liability concerns. [This message was edited by survey tech on January 31, 2003 at 07:26 PM.]

Thats right, although some here rebeled when I said the same thing several months ago, its best to refrain from sending any recreational coordinates to NGS. They will not supplant the existing professional coordinates as a matter of policy, even though they may be better than the scaled coordinates, as has often been mentioned here. If you list the coordinates within the text of your description your submission may or may not be used, which is what I was referring to above about creating confusion in the datasheets. For those who cannot resist the urge to publish their own personal coordinates, using the handheld disclaimer is a way of preventing any potential confusion as a courtesy to future readers of the datasheets who may eventually be confronted with long descriptions replete with varying coordinates for markers that have been frequently visited by GPS enthusiasts.

Anyone is welcome to submit updated description data, but only professionals may update coordinates due to the rigorous precision restrictions which are in place to maintain the integrity of the data. One may express one's opinion about the status of a marker that one did not find, but should refrain from jumping to conclusions and pronouncing it destroyed without positive proof. Likewise, positive identification of the marker, usually by matching the stamping exactly with the deignation given on the datasheet, is needed to pronounce a marker found. The older markers are just as important and valuable as the newer ones, and while the NGS is not vitally interested in recording them anymore, this should not be misunderstood to indicate that they are no longer important.

I agree with El Oso also. As I have said before, A carefully updated description of the vicinity, whether you actually find the marker or not, is the most beneficial thing one can provide for anyone, surveyors or geocachers, who may follow. In some cases, where the scene has changed drastically and few or no original objects remain, the description may seem to point to the likelyhood of the demise of the marker, and one may even state one's inclination to believe that it is gone, without going so far as to declare it categorically destroyed. Read a number of the better existing NGS descriptions and you will see many good examples of this. If you choose to mention the coordinates you obtain in a recovery note to NGS, it would be prudent and helpful to specifically state that they were derived from a handheld unit to avoid any confusion

The magnets are not large enough to deflect a compass beyond a distance of a few feet and most markers do not contain magnets anyway, although those in your area may be an exception to this.

The NGS is no longer in the business of replacing ground markers. They have moved on to other things, such as the CORS project. These markers never belonged to the NGS. They were set because there was a need, sufficient to mandate doing so, and a federal agency was the logical means of accomplishing such a wide ranging task. The markers as they sit now are essential tools of local surveyors and engineers everywhere, for whose benefit they were specifically set, and who therefore naturally bear the responsibility for preserving, maintaining and replacing them, which is why surveyors occasionally visit here and express concerns about what the fate of the markers may be. Ironically, a great many markers have been deliberately destroyed down through the years by people with some grudge against the government, who read the federal stamping and imagine they are getting some form of revenge against the feds by destroying it, while nothing could be further from the truth, so at least some of that concern is justified