Kewaneh & Shark

The coordinates are very close to a PLSS section corner location and it is located approximately one mile north of the Township corner. It is also about a mile east of the city limit line of Clinton, Ill. It could be a marker or type of witness post for the section corner. It could be the actual corner, too, but the type of construction (stone column) is an antiquated style, and it looks fairly new. The markings are unfamiliar as well. Were there other markings on the other sides of the column? Columns used for PLSS corners should have different markings on each side of the column. - Kewaneh

Being a surveyor sometimes gets you clearance to areas that others might not get to go, like airports. I worked on a job a few years ago that required me to occupy two marks that were in the restricted area of the Madera Airport, in Madera County, California. One of the marks, GU4273, was located adjacent to the taxiway leading from the hangars, the other, GU4283, was near the runway approach apron. This is not a large airport - mostly light planes with no big commercial flights - but it is busy, and we did need clearance from the airport admin. I was also able to find two other marks while I was on that project, GU1086 & GU3358. While the marks are not in restricted areas, they are in a quasi-private area of the airport near some of the hangar rows. GU4273 - Madera Airport, Madera County, California Designation: FAA MAE A GU4283 - Madera Airport, Madera County, California Designation: MADEPORT AZ MK - Kewaneh

Fresno County, California still uses paper copies of their benchmark list. An online listing has been rumored for some time, but nothing as of yet. The City of Fresno does have an online listing. State: California County: Fresno City: Fresno Link: City of Fresno Benchmark Review The terms Geomatics and Geomatic Engineering are newer buzzwords (to Americans) in some circles, particularly in the area of education. Most old school surveyors prefer the term Land Surveyor and/or surveying, but 'Geomatics' - which means 'World Measurement' - is catching on. 'Land Surveyor' is pretty much an American term. Most of the world, including Canada, calls surveyors 'Geometers', 'Geometres', or 'Geomaticians'. Geomatics, or Geometrics, is the practice of the measurement of land and the world, with the focus being more on the world aspect of it. In the U.S., Geodisists (like DaveD) have traditionally done the ultra-large, world measurement surveys. Land surveyors worked on a smaller (sometimes much smaller) level. Land surveyors have always concerned themselves with the methods used to perform large-scale surveys, and the current use of GPS has brought that concern into a surveyor's daily life. A small project can now easily be positioned on a global scale, making the fact that land surveyors really are 'world measurers', much more obvious than before. Reconnaisance, or 'recon' is a term used by surveyors for fieldwork done prior to the actual measurement portion of the field work. It is done at the beginnings of a survey project, to locate existing field control, like benchmarks and tri-stations, to find local system benchmarks, to set initial project survey control, and to locate any possible obstacles that may be encountered during the survey. It is also sometimes used to determine which equipment to be used for which portions of the project. (GPS is always nice to use, however, many projects require more traditional survey methods such as theodolites and levels.) Site recon may only take a few minutes or it may take a few days (or weeks) depending on the size and complexity of the survey site. Some larger survey firms which specialize in larger projects, may have survey crews that only perform site recon, leaving the site measurements to another crew, and then, possibly, the stake-out portions of the project to yet another crew. In smaller survey and engineering firms, the same crew does every part of the project for recon & design, to execution and follow-up. - Kewaneh

I must be a favored mark hunter as I have seen several marks used. What kind of mark hunter are you when you actually use them? This is GT2079 that I found (and used) on May 3rd, 2006. Ralann - the jackhammer/grinder process you describe is how I occasionally have to set property corners and section corners in the valley hardpan. (Hardpan is like naturally occuring concrete.) Of course, I'm only setting them about 3'-5' down - much easier than 30+ feet. And, along with everyone else, I'll also have to admit a bit of envy at your opportunity to help the crew set the mark. It is a rare opportunity, to say the least, even for surveyors. MLoser - next time I know I'll be using an established and published NGS mark, I'll let you know and you can tag along. - Kewaneh

The PLS number is not a disk ID, but a Professional Land Surveyor (PLS) license number. It is the identification number of the surveyor who set the mark. (Some States use RLS for Registered Land Surveyor, or simply LS for Land Surveyor.) PLS4541 is a Mr. Frederick W. Orban, of Las Vegas. He has been licensed since 1977 and his license is current through 2007. (This is public information that can be found through the Nevada State Board of Engineers and Land Surveyors. Their license holders are listed here.) As stated on the disk, it is a right-of-way monument for Las Vegas Boulevard. The number 055 may or may not be a series number, but it certainly is for mark identification purposes. Most roadways and highways have some sort of right-of-way monumentation, either on the right-of-way lines or along the centerlines (and sometimes both). In this case, the right-of-way line would most likely be defined by the small divot in the middle of the cap, at the center of the 'V' in Vegas. It's easy to see that the City of Las Vegas spent a bit on their street monumentation; they have the money, so why not. Most areas and cities, use much less extravagant methods of monumentation. Additional information about this mark, and the others, could be found by contacting the Clark County Department of Public Works (which the County Surveyor is a part of) and you can find more information about surveying in Nevada on the Nevada Association of Land Surveyors website. - Kewaneh

I'm going to add my cautions to Z15's already well-said advice: If there is a dispute over the position of a boundary line, it is in the best interest of BOTH owners to seek the advice of a professional surveyor. Every land ownership boundary line in the U.S. is described and/or defined by a map or deed. In order to retrace that line accurately (ie: in its proper position) the research must be done to ensure that the footsteps of the original setting surveyor are being followed. That research usually begins at a County level (as mentioned by Holograph) and may require research of adjoining properties to find the necessary evidence to determine proper location of lines and corner monumentation (if any). Angular measurements are defined using compass bearings and distances are usually in decimal feet. Older maps, from the early 1900's and older, use survey chains (not feet) for distance. Some maps in some parts of the country use metrics. Coordinates of any kind (geodetic, State Plane, or other) are very rarely used to define the position of property boundaries and corners. While a handheld GPSr is useful for somethings, determining property boundary and corner location is not one of them, and attempting to locate a line in question with one could create more confusion, particularly if the intent is to set a marker. (It should be noted that looking for a particular property corner for the sake of curiousity is perfectly fine, however, attempting to do survey work in order to define a property corner or boundary is illegal to do unless you are licensed as a Land Surveyor.) I am presently involved in a property dispute over a PLSS corner position. Both properties are in the east half of a section and the dispute is over the line between the northeast quarter and the southeast quarter, between the east quarter corner and the center quarter corner. I found the east quarter corner as described on three maps dated 1941, 1979, & 1980, but the problem lies with the center quarter corner. Yesterday I found a monument described on a map dated 1979 describing the positional perpetuation of a redwood post found in 1901 which was accepted at that time to be the center quarter corner. Along with it I found a 2nd monument, 18.6 feet northerly of the 1st, described as the center quarter corner on a map dated 1980, and referencing the 1941 map and an 1880 map. I also have other evidence that shows that both monuments may be incorrectly positioned. One of the first things that happened, at the beginning of this present dispute, involved one of the landowners, a handheld GPSr, and a now new fence which isn't very close to either of the monuments I found. There are now lawyers involved, a judge, a couple of Sheriff's deputies and a restraining order against one of the owners. The maps show that the boundary dispute is not new (although both properties were under different ownership at the time of the 1979/1980 maps), but the resulting actions taken by both present owners is going to leave some bad blood between them for a long time. Very bad news for adjacent farmers. Again, if there is a dispute, hire a professional. It may be expensive, but nowhere near as expensive as years of feuding with a neighbor. If the neighbors are still on relatively good terms, have them hire the surveyor together, that way neither one feels that the surveyor is favoring the other, and they can split the cost. Just be ready to accept what the surveyor finds and shows you, have him or her map their findings and record them with the County, and get the dispute as far behind you as you can. - Kewaneh

The answer is 'sort of'. There are (or were at one time) apparently two marks either adjacent to, or on top of each other. You were looking for MF0171 , PBM 96 BOLT USE, but MF0172, PBM 96 CAP USE has the same coordinates and virtually the same description. MF0171 is described as '...A COPPER BOLT SET IN A LIMESTONE SLAB DIRECTLY BENEATH PBM 96 (CAP)'. MF0172 is described as '...ON THE TOP OF A PIPE PROJECTING 16-INCHES'. These two marks are not the same mark, however it could be implied that it was intended that they work together, probably similar to a tri-station and its underground mark. While the pipe is technically not a part of the mark you were searching for, it could be used as evidence to identify the location of that mark. - Kewaneh

Your coordinates could very well be on a local & assumed system. It is a very common practice, at the beginnings of a project, to assume a coordinate system, and at times, an elevation (datum). Through the course of a project, if reference to an established coordinate system or datum is required, the proper calculations can be made to transform the existing data. If there is no such requirement, and most times there is not, the local system is maintained throughout the course of the project. This coordinate system is for internal, calculative purposes only, and (very) rarely published or shown on a map. State laws govern accuracy standards, mapping standards, and State Plane coordinate system use standards, not coordinates systems to be used by surveyors on a day to day basis. State law can require that if a coordinate system is to be published on a map, that it meet a certain criteria, or that it be in a particular system for a particular type of map. The advent of GPS has had nothing to do with this. State Plane coordinate systems, their use, and the laws that govern them, have been around for years. What GPS has done is made the use of such systems easier, but assumed coordinates systems are still used on a daily basis because of their simplicity and ease of use. - Kewaneh

Assuming your coordinates are UTM coordinates, the easiest thing to do would be to set your GPSr to UTM as it's primary units and then go hunting. If the units are State Plane (I believe Oregon has 2 State Plans zones which run east/west), the only reliable conversion program you can use would be the NGS conversion programs linked by Holograph above. In the UTM system, the zones run in a north/south direction and the northing units are larger than the easting units. for example, the UTM coordinates for Salem, Oregon are UTM 10 497231E 4976608N. (The northing is nearly 5 million, but the easting is less than half a million.) If you don't know from your coordinate list which numbers are the northings and which are the eastings, change the primary units in the GPSr and go outside and let it show you where you are. The numbers it shows and the numbers on the coordinate list should be similar. - Kewaneh

The purpose of the witness post is to aid in the finding and recovery of the mark in question. It is very common for the marks to get buried and digging for them is, in many cases, necessary. The digging should be done as prudently as possible though. As a general rule, the witness posts are placed in relatively close proximity to the mark. Also, they usually point toward the mark (so you can read the witness post if you're standing on the mark). Read the data sheet (or any other information you may have about the mark) to see if the distance between the mark and the post is called out. If it is, start there, if not, start about a foot in front of the post and work your way out. It's best to start by probing a bit. You can use a probe if you have one. A shovel can be used in a similar manner without disturbing too much soil but they usually can't go as deep. I tend to just kick the dirt and/or weeds out of the way with my boots and 'feel around' for it. Then I start digging. The warning has already been given but I'll restate it: always ask permission before digging on private property. Most property owners wouldn't mind you looking for a survey marker on their property provided you're not damaging or destroying something. Doing so without asking prior permission may put you at the business end of a vandalism or criminal trespass lawsuit. Don't go there. I believe the GC.com search function needs more than three characters to work. There could be a JIM mark in Colorado, but it needs more than just JIM to work with. (Some of the others may want to chime in here to verify or dispute this.) If you've used the coordinates to perform a search and found a mark that fits that description - from the setting to the stamping to the ties (if any) - then it's most likely the correct mark. If you still have questions, let the forum know the PID (benchmark number) of the mark in question, and post a picture (or good description) of the mark. There are many people here who can help you with an answer. - Kewaneh

Berntsen and Mark-It are two of the larger survey monument suppliers for surveyors & engineers. These are the real things - no fakes. They would most likely be able to get you what you are looking for. - Kewaneh

From the National Geodetic Survey Frequently Asked Questions page: The North American Datum of 1927 (NAD 27) is "The horizontal control datum for the United States that (was) defined by (a) location and azimuth on the Clarke spheroid of 1866, with origin at (the survey station) Meades Ranch." ... The geoidal height at Meades Ranch (was) assumed to be zero. "Geodetic positions on the North American Datum of 1927 were derived from the (coordinates of and an azimuth at Meades Ranch) through a readjustment of the triangulation of the entire network in which Laplace azimuths were introduced, and the Bowie method was used." (Geodetic Glossary, pp. 57) - Kewaneh

In geognerd's above reply, the Other Topic Discussing the Same Thing he links to was started in the Benchmark Forum by one of the forum's frequent visitor's, DaveD. The topic of datums is frequently discussed in that forum as benchmarks are listed in the NAD83 and NAD27 datums, not WGS84, and he began that thread as an explanation to the datum differences. (The ensuing discussion can get a bit longwinded, but there is much information to be found in it too.) It should be noted here that DaveD is neither a cacher or a benchmark hunter (in the GC.com sense). He is a Geodesist for the National Geodetic Survey (a branch of the NOAA), with an interest in the benchmark hunting side of geocaching. His office is responsible for the maintenence of one of the Nation's largest survey network databases. It should also be said that he is the nation's formost expert on survey datums. He quite literally helped to define both the NAD83 and WGS84 datums we all use today. - Kewaneh

I've already got four. I don't need another. - Kewaneh

Check out this thread from January 2005: Canadian Benchmark Hunting, Benchmark hunting in Canada Hope this helps! - Kewaneh

Even high-precision, survey-grade GPS systems still need benchmarks to determine an elevation for a particular area. The elevations (aka orthometric height) of most areas are relative to mean sea level, but GPS systems - survey-grade, GIS-grade, and recreational units - all determine an ellipsoidal height, which is relative to a mathmatical model of the earth. That ellipsoidal height can be substantially different from the orthometric height (elevation). While survey-grade systems have the ability to be very accurate both horizontally and vertically (<1cm), a benchmark is still necessary to calibrate the system to the area's elevation. - Kewaneh

As a general rule, we try not to look at the hint until we've looked for it for a few minutes, but whether or not we'll decrypt it before we leave home sometimes depends on who hid the cache (See rant below). Because we cache with with kids with short attention spans, we may look a bit sooner than most. If we're caching paperless, we won't decrypt it until we're at the cache site and out of options. If we've got a printed cache page, usually we'll decrypt it before we leave the house and try not to look at the hint until we need it. <RANT> I've noticed this correlation too. Thoughtless 'hint = thoughtless 'hide'. There are exceptions to this, but they are seemingly few. I've also noticed that certain cachers are more prone to give a useless hint that others, consequently, we tend to avoid caches hidden by those cachers. I subscribe to the school of thought that I WANT people to find my caches (muggles notwithstanding). A hint is to help them do that. I've found that if the decrypted hint is something like 'too easy for a hint' or 'It's a 1/1, you don't need one', or some other type of non-hint, the cache is probably a spur of the moment film canister hide in a bush or rock pile with coordinates that are less than spot-on. I don't have the patience to look for 90 minutes for one smiley at a thoughtless cache site. (A 90 minute hike to a nice view is well worth it, smiley or not!) I've got to a point in my caching career where I don't need to log every hide and the given 'hint' helps filter the good hides from the trash. </RANT> - Kewaneh

Benchmarks are still being placed, they are however, they are not set as often. The national agencies that used to actively set the marks don't get out as much as they used to. Usually the work falls to local agencies, sometimes under the direction of the national agencies. It could be in your area that 1972 was the last time that the area was actively worked. In my area, the marks are clustered with dates in the early to mid 40's, and again in the late 60's, but there are marks with dates scattered in between too. The advent of GPS has not made benchmarks any less important. Benchmarks are part of what defines GPS - at least the help to define the shape of the Earth and the Datum that GPS uses. One thing that GPS has done to benchmarks is made it possible for the marks to be spaced a bit farther apart. With that, farther spacing equals fewer benchmarks. - Kewaneh

The gauges may still be in use. It would depend on whether or not the water would still need to be monitored or not. The only way to know for sure would be to contact the agency that monitors the gauges. I frequently work near the California Aqueduct, a canal that moves water from the San Francisco Bay Area to the LA Basin. It is heavily monitored by the Department of Water Rescources and the Army Corps of Engineers for movement. This is not a small undertaking considering that it's over 400 miles long and portions of it parallel the San Andreas Fault. It is consequently heavily benchmarked, and many of these marks are placed at the bases of gauging/monitoring stations. This is what the monitoring stations look like near the aqueduct and they are very much in use. Benchmarks GU1472 and GU1477 are located at the base of these monitoring stations. Yours may look similar. The view southeasterly down the California Aquaduct showing the recorder station. GU1472 is at the base. The view southeast down the California Aquaduct showing the recorder station. GU1477 is at the base. - Kewaneh

In function, tidal benchmarks are just like regular benchmarks - a vertical reference point - and they are used in a similar manner. The difference is usually the datum being referenced. The 'regular' benchmarks are now referenced to the North American Vertical Datum of 1988 (NAVD 88). Tidal benchmarks reference a local tidal datum which are defined by a phase of the tide in a local area. NAVD 88 and local tidal datums are different. There are also differences between tidal datums in different areas. The marks are clustered to help define the datum in that local area. - Kewaneh

A boundary marker would be a good hunch. Many government lands, including military bases, can be identified by the fairly large or otherwise prominent posts used to mark their boundaries. Do you have a picture and/or coordinates of the marker in question. There are many people who frequent this forum who may be able to identify it, and the additional information would help to narrow down the possibilities. - Kewaneh

Above and beyond, Photobuff. Well done and keep it up. - Kewaneh

I know plenty of cachers who wouldn't even flinch a little bit of bushwacking. Some would even look forward to it. Placing a cache near a mark may even introduce some cachers to benchmark and benchmarking. I have three caches which see. use, or otherwise identify a nearby benchmark. None require a great deal of bushwacking (or even walking for that matter), but all of the benchmarks are logable on GC.com and many cachers have said in their posts that it was the first benchmark they'd found and logged. See GCD754, Do not pass GO. Do not collect $200 for an example. Keep on Caching! - Kewaneh

Grid azimuth is simply using true North as a basis of bearing. An azimuth bearing of 157 degrees should be, as you suspect, south and east of the original position. I think you may have put the data into the FORWARD incorrectly. When I look at your numbers, your results look to me to be due North of your starting position. From the datasheet as shown on your post: Lat: 35 05 53.99253 (N) Long: 089 14 53.51921 (W) Your results as shown on your post: Lat: 35 05 54.99229 (N) Long: 089 14 53.51921 (W) Deltas: Lat: 00 00 00.99976 (N) Long: 000 00 00.00000 (W) Obviously not the intended position from the setting survey crew, or the intended results from you. When I run your data through FORWARD, these are my results: Deltas: Lat: 00 00 00.92074 (S) Long: 000 00 00.47401 (W) You may need to be sure that you completely 'spell out' all of the bearings when you use the FORWARD program. For example, the azimuth as shown on the datasheet is 157 04. When that is put into the FORWARD program, it should be input as 157 04 00. Hope this helps. - Kewaneh

A ridgeline is the continuous top or peak of a line of hills or mountains. Think of the roof on a house: where the slopes meet is the peak, the line of that peak is the ridge, or ridgeline.