Kewaneh & Shark

Many States have a 'Right of Entry' law for surveying purposes on the books. Those laws allow the surveyor to accomplish his task without the fear of breaking any trespass laws, whether or not the property is fenced or posted. However, it IS in the surveyor's best interest to ask permission if possible. Knocking on a door or two and letting the property owner or resident know who you are and what you're up to can solve a multitude of problems before they happen. I probably does not need to be said, but it should be noted that a recreational benchmark hunter is not performing a survey, and is still very much subject to any trespass laws. From the California Business & Professions Code, Section 8774: ( a ) The right of entry upon or to real property to investigate and utilize boundary evidence, and to perform surveys, is a right of persons legally authorized to practice land surveying, and it is the responsibility of the owner or tenant who owns or controls property to provide reasonable access without undue delay. The right of entry is not contingent upon the provision of prior notice to the owner or tenant. However, the owner or tenant shall be notified of the proposed time of entry where practicable. ( b ) The requirements of subdivision (a) do not apply to monuments within access-controlled portions of freeways. ( c ) When required for a property survey, monuments within a freeway right-of-way shall be referenced to usable points outside the access control line by the agency having jurisdiction over the freeway when requested in writing by the registered civil engineer or licensed land surveyor who is to perform the property survey. The work shall be done within a reasonable time period by the agency in direct cooperation with the engineer or surveyor and at no charge to him or her. Keep in mind that you DO give the power company the permission to read your meter every time you use their power and send them a check for it. You have the right to use a particular utility and they have the right to monitor your usage. You don't have to let them read your meter, and they don't have to send any power through that meter. - Kewaneh

From the Pocket Query page: Pocket Queries are custom geocache queries you can have emailed to you on a daily or weekly basis. They are in a format you can bring along with you on cache hunts on your GPS and/or PDA. You can select a GPX or LOC text file and/or MobiPocket eBook format that works with supported software applications. Because of the detailed queries, each search can run only once per day. You have up to 5 pocket queries run every 24 hour period. - Kewaneh

I can remember when using a cell phone to contact a fellow cacher for a hint while you were at the cache site was unheard of. I can also remember when 'tele-caching' was just considered bad form. (Of course, I still think it is.) It seems to be the norm in some places now. Keep on Caching! - Kewaneh

I noticed this feature about a week ago and thought it was a nice touch - gives kind of a sense of place to this virtual forum world we all get lost in. (My apologies to the sense of place geo-stuff we're all here for in the first place.) My 'from' doesn't seem to show under my avitar whether I'm logged in or out though. I've checked my edit profile page and the 'from' dialog box is filled in. Thankfully I know where I am.... I think. Any ideas? - Kewaneh (maybe lost)

Using trees as reference points for survey marks has been practiced for many years. They are still described as standard marks, and the proper method for using and describing them as such, is still published in many current surveying manuals, including the United States Public Lands Survey System Manual of Instructions. Many years ago, before development was rampant, trees would stand nearly forever, and could be an excellent reference, even though the tree would obviously grow. When searching for a mark that uses trees as a reference, take into account the amount of time that has passed since the description was made and look for an appropriately sized tree or stump. Whether the reference is natural or man-made, nothing is truly permanent. Every surveyor who puts a point in the ground knows there's a possibility that it may get damaged or destroyed. Reference marks also have that possibility, whether that reference is to a tree, a power pole, a building, or a bridge. - Kewaneh

All of the above. There are many rail lines that have been abandoned and the tracks removed that remain owned by the rail lines. Sometimes the right-of-way is donated to a park or trail concervancy. It can also be purchased by adjacent land owners, or the local city or county government. I worked on a boundary job for a local county a few years back that involved a six-mile stretch of abandoned railroad right-of-way. Within that six miles, the right-of-way had been divided, and redivided into no less than 44 different parcels - some owned publicly (for park purposes), some owned privately (by adjacent land owners), and some was still owned by the railroad that had abandoned the line in the 1930's. - Kewaneh

Let's not confuse GPS measurements with photogrammetry. GPS systems use radio waves of a known wavelengths to measure the distance from the satellite to a GPS receiver on the ground. Through triangulation, a position for the receiver can be calculated. The GPS satellites can't actually 'see' anything as they have no cameras. 'Hearing' is probably a better term as the GPS receivers actually listen for the signals from the satellites. Aerial photogrammetry uses a camera to take a picture of the ground from (mostly) directly above. The aerial targets are used to show common points between images (many times the images are sequential), and to help the photogrammetrist 'ortho-rectify' the image. A surveyor provides x,y,z, coordinate information to the photogrammetrist to help them with stitching the images together for the mapping processes they perform. - Kewaneh

So, I take it that your opinion is that unless we are a professional surveyor like yourself, we should always answer the NGS satellite suitability question (that appears at the last phase of logging at the NGS website) with I don't know. BDT - My explanations are not intended to be as extreme as 'If you're not a professional, don't make the suitable/unsuitable call'. I'm only trying to explain that there are times when making the determination as to whether a site is suitable or not is more complex than counting tall objects on the horizon. There are times when unsuitability is very obvious, like marks under heavy tree cover, marks placed in heavy urban or downtown area with many tall buildings, or the often mentioned indoor benchmarks. There are others which are obviously suitable, like many of those found on mountain tops, open plains, and the deserts of the southwest. In cases like these, (and many others, I'm sure), make the call. My explanations are to express that caution be used when making a suitable/unsuitable determination, particularly if you plan on reporting the mark to the NGS. Because the NGS database is generally used by professionals for professional work, care should be taken when making a claim about a mark. This is similar to the declaration of mark being destroyed - destroyed on GC.com and at the NGS are different, and a mark declared destroyed by a recreational benchmark hunter may still be usable by a surveyor. Many times it's a simple call, other times, it's not so simple. Use caution when making particular claims about a mark if you plan on logging it to the NGS. If you're sure it's suitable (or destroyed), report it as such; if you're unsure, write to the NGS and ask, log it as 'I don't know', or don't provide information that indicates an opinion either way. - Kewaneh

It would be nice if there was a simple formula to determine whether or not a site was observable, but there isn't. That determination involves more than just what is on the horizon, or just above it. Much of it is based on experience and professional site interpretation, proper planning prior to the site visit (using sky plots and DOP charts), and the ability to know the strengths and weaknesses of the equipment to be used in order to achieve the desired results. Signal problems and interference are only one of the criteria used to determine site suitablilty. In addition to trees and buildings, problems can be caused by overhead and/or nearby power lines (usually well above the horizon), chain link fences, even large bodies of water (at, or below, the horizon). I once screwed up an occupation by parking my truck too close to the antenna, which was much higher than my truck. The horizon at a given station can be a relative thing. The effective horizon for GPS station set-up is determined by the antenna height of the GPS station, not the eye, or shoulder height of the user. In my GPS work, I use a fixed height, 2.250 or 2.333 meter (about 7.5') tripod to set my station antenna on. If the station mark is elevated at all, the antenna is even higher, and consequently, so is the effective horizon. There can also be physical obstacles which prevent the proper, or safe, set up of a tripod or other equipment that deem the site unsuitable. A station set on a steep hillside, on the edge of a building roof top, or a mark set on the top of headwall of a railroad trestle abutment can all make for precarious positioning. I know of one mark set in an airport runway apron. While it has a perfect view of the sky, it's also in line with the port-side landing gear of the incoming 767s and DC-10s. A technically suitable mark, but I wouldn't want to occupy it. (And hoping the airport would close runway two-niner left for a few hours is out of the question.) It should be remembered that the term 'suitable for satellite observations' is not only a relative term (as mentioned in my post from yesterday), it is a technical term used by surveyors and engineers to describe a technical aspect of the marks. There is much more to it than counting nearby trees. - Kewaneh

The term 'suitable for satellite observations' can be a relative term. Sites which were marginally suitable (or questionable) years ago at the advent of GPS, may be suitable now due to newer technologies and more satellites. Some sites which were unsuitable, may be marginal, or even suitable now with a little bit of work. Not withstanding, a tree, building, or mountain will always be in the way if it's between the receiver and the satellite, no matter how good the technology is. It has already been said that this term is intended for survey-grade GPS systems. This term does not apply to recreational grade GPSrs with a 10, or even 5 meter accuracy at best. The loss of a signal, whether momentarily or longer, from one or two satellites will not make much of a difference on the already large inherent error of the unit. Most survey systems measure sub-centimeter, often in the 3-5 millimeter range. A signal loss there can wreak havoc on the data and the positional results. With older types of surveying (non-GPS), 'line of sight' was always critical. The instrument man needed to be able to see the rod man in order to take a measurement. That 'line of sight' is still important now, it's just that there are multiple rodmen (the satellites), and they're in the sky. Care must always be taken so the instrument man (the GPS receiver) can see them. - Kewaneh

Along with the quality of signal reception theory: different models of GPSr may have different types of antennas, which can affect that quality of reception. Make sure that you hold the GPSr away from your body and that the top of your GPSr is generally pointed upward for the best signal reception. WAAS could have also been a factor. Did your friends have the WAAS capabilities turned on on their units while yours was turned off (or vice versa)? If your ETrex has WAAS capabilities, turn it on and the inherent error of your GPSr will be about cut in half. - Kewaneh

I use a Magellan Meridian Gold that spends much of its time attached to the handlebars of a motorcycle. The screen is large and easy to read, and the buttons are big enough to use at freeway speeds with winter gloves on. It does well enough under tree cover that I have no complaints, but the truth is, tree cover will give EVERY GPSr fits, regardless of make or claims. (That includes the very high-dollar, survey-grade GPS systems.) Some recreational units just handle it better than others and the MeriGold does fine, particularly if the WAAS is locked on. The MeriGold is an older unit, but it has SD expandable memory, computer connectivity, and can be powered externally. Mine is more than three years old and is seemingly bullet-proof. I use mine for commuting, traveling and for work, and there are many days where the unit is left running for 8-10 hours at at time. Prices are in the $200-$300 +/- range. If you want to stick with Garmin, I know that the GPS V is an excellent unit, and can be attached to a motorcycle easily. Price and features (and age) are similar to the Meridian Gold. I think the buttons would be a bit small to use while riding though. - Kewaneh

Cadastral surveying deals with the measurement of land boundaries and most generally applies to surveys of the Public Land Survey System (PLSS), but can also include parcel and tract boundaries, and limits of ownership or land use. Cadastral surveys are horizontal only in nature as there is no vertical component. They are a two-dimensional type of land measurement. Geodetic surveying is three-dimensional and used to help define the shape of a particular area of land, land mass, or the earth. Geodetic surveying uses both triangulation stations (horizontal) and true benchmarks (vertical). These are the marks that are primarily in the NGS database. While the triangulation stations used may not have a vertical component applied to them, the vertical angles between the stations are measured along with the horizontal angles in order to define the shape of said area of land. The triangles are then linked together to model that shape. From this type of measurement, and the resulting mathmatical calculations, map datums (ie. NAD 27, NAD 83, & WGS 84) can be defined, and refined. Geodetic surveys are generally used as survey control points and/or positions used to define other smaller control networks and surveys, done on a more local level. - Kewaneh

The stampings of the mark you found show it to be LY0675, but the description for LY0675 states that it's '... ABOUT 3 FEET HIGHER THAN THE TOP OF THE RAIL'. Aren't the rails up on the bridge deck? Your picture of LY0675 show that it's well below the rails. I wonder if the descriptions got mixed up and the chiseled cross of LY0677 is actually on the abutment above the track. - Kewaneh

As a general rule, triangulation stations are set with five seperate marks: a surface station, and underground station, at least two reference monuments, and an azimuth mark. The triangulation (surface) station is identified with a triangle in the center, as shown on the mark in Shirley's post. It is stamped with the name of the station and usually the date it was set. The underground mark is stamped identical to the surface station, usually about 3-5 feet down and exactly below the surface monument. It is used to relocate (or use as the station) in the event that the surface station is lost. This is the most important mark of the the group, and the point from where all geodetic and survey measurements were taken. The reference monuments are identified with an arrow in the center, and stamped with the name of the station, the reference mark number (RM#1, RM#2, etc), and the date the reference mark was set. The set date for the RMs are usually the same as the set date for the station, but not always. Reference monuments that get replaced are stamped with the newer dates and usually have a higher RM number (RM#3, RM#4, etc). [i have found triangulation stations with up to five RMs, with the first three RMs confirmed missing. Also, I couldn't find RM#4 and only found RM#5.] Generally the reference monuments are set within 100 feet of the station. The setting surveyors used 100 foot, steel tapes for measuring and wanted to be able to set the RMs on one pull of the tape. The reference monuments are accessory monuments used to locate and verify the position of the main station. The azimuth mark was set some distance away from the main station, often a half mile or more. The azimuth mark is also identified with an arrow in the center, and stamped with the name of the station. Instead of a number, it is marked 'AZIMUTH' or 'AZM'. The purpose of an azimuth mark was/is to orient a compass and to provide surveyors with a compass bearing, or azimuth, of a known line (with the station mark being on one end and the azimuth on the other), and ultimately identify true north without relying on astronomic calculations. Also, from the Benchmark FAQs: Also, a quick search of 'azimuth mark' in the benchmark forum turned up these additional threads. (I only went back a year, but there are more.) A Little Help Please, Finding RM's and a Azimuth mark? Where Does Arrow On Disc Point To?, Does the bearing indicated have meaning? Do The Arrows On Reference Marks Point Exactly To, the benchmark just generally toward it? Station Marks And Reference Marks - Kewaneh

When you say all sats show as '14', does that mean that you show ten satellites all labeled as #14, or that you only get a signal from #14 and no other satellites? If multiple sats are showing as the same number, or the signals from one sat is getting multiplied, it's probably (hopefully) a firmware issue. An update may solve the problem. If not, it may require service from Magellan. If your GPSr is only finding one satellite, your unit may be 'lost' and a re-initialization should solve the problem. As far as the satellites today, they're working fine. I used GPS for about 7 hours today with not even a hiccup. - Kewaneh

A surveyor's steel tape is heavier and a bit stiffer than a fiberglass tape. They are not blown around as easily and are not as prone to stretching as a fiberglass or cloth tape can be. However, they are also not as easy to find and much easier to damage (by kinking or breaking). If measuring shorter segments (called 'breaking chain' by surveyors, particularly on sloped surfaces) is the preferred measurement method, a surveyor's set of 'chaining pins' would help. The pins are 14 inches long, pointed on one end with a loop on the other, and come in sets of eleven for about $20. Many surveyor's supply stores carry them including Forestry-Suppliers and Hayes Instrument. - Kewaneh

For the purposes of geocaching and benchmark hunting with a recreational GPSr, the NAD83 and WGS84 datums are identical. There is no real need to switch the datums to hunt either caches or benchmarks. The positional differences between the datum origins is relatively small (<3') and should only be of concern if you are using high precision, survey-grade GPS equipment. - Kewaneh

Microsoft Paint, which is bundled with any Windows system, allows you stretch an image in one direction. That may work for you. - Kewaneh

The mark has obviously been tampered with, but I would doubt that a survey crew removed the mark. I would believe the possibility that a crew installed the pipe as a long distance backsight, of sorts, after finding the mark missing. There are, however, many methods of creating a semi-permanent backsight over an existing point without damaging, let alone removing, said point, so a surveyor would not have removed a mark for that purpose. The removal could have happened any number of ways. Vandalism is one possibility. Heavy equipment is another possibility, and the first thing that came to my mind. You mentioned in your logs that on your first visit that you did not find RM#4 due to brush, but you found it on your return visit. What removed the brush to allow you to find it? In my area, it is not uncommon for large agricultural equipment to damage, and remove, benchmarks. Not just the marks from the settings, but the entire settings as well. It is also not uncommon to find marks 'protected' from equipment by tall pieces of PVC or steel pipe painted white. That sort of 'protection' is usually not installed by surveyors, but usually by the farming companies who understand what the marks represent. (In most cases, the guy driving the tractor doesn't know, or care, what a benchmark is, but a tall white pipe sticking out of the ground, that looks like a part of an irrigation system will get a wide berth.) This ag-land scenerio is probably not the case in a State owned wilderness area, but large equipment is used there too, and an 8 foot tall piece of PVC probably stands above the brush higher than a witness post that would have been installed by any surveyor. It would likely stand as a 'protection post' for not only the mark, but the RMs too. The datasheet says that the mark is an NGS Benchmark, although it is/was set by the Orange County Surveyor's office. The stamping and original description indicate that. Given that the mark is the County's, they have the right to do what ever they want to with it, whether or not the mark has been incorporated into the NGS database. The mark belongs to the County, the NGS only distributes the associated data. There is a possibility that the County is in the process of maintaining and/or updating their survey network. That maintenence may include the repair and replacement of any marks. The fact that you found RM#3 & RM#4 still intact mean that replacement is possible, and that it could be every bit as accurate as the original. You can contact the County Surveyor's office and they be able to provide more information on this mark and it's condition. Asking for additional information from them may be a good idea prior to submiting a report to the NGS. They may have plans to replace it next week. - Kewaneh

I would imagine that it could be a lightning strike that would cause damage like that. I haven't seen many things that have been struck by lightning, let alone a brass cap, so I have nothing to compare it to. Benchmarks, and triangulation stations & their reference monuments, are commonly set in high locations. Exposed metal on a high peak would be a good target for an electrical storm. The damage could be man-made as well, although most man-made damage done after the mark is set, is in the form of scrapes and dents, not chipped holes. (Or melted or burned holes, for that matter.) Or, it could be a flaw in the brass too. The only person who would know for sure is the person who actually did the damage, be that man, or God, or Mother Nature. - Kewaneh

I'm not familiar with that brand or model of unit, but any recreational handheld GPSr won't get you much better than 10 meter (33 feet) accuracy. A WAAS or DGPS enabled unit will nearly cut that error in half and get you within about 5 meters (16 feet). Usually, GPSrs show position well within those areas of accuracy, given good conditions. If the benchmark you're using has known, high-accuracy (survey grade, not scaled) coordinates for it, and your handheld unit is showing that you're within three feet of the mark, consider yourself on the mark. It won't get much better than that. - Kewaneh

We have a few options. When it's the whole family, it's a 2005 Honda Odessey. Lots of room for everyone and easy in & out for when we get to the cache sites. When it's just me, it's a 1993 BMW R100GS. Not the easiest motorcycle to look at, but it gets me everywhere I want to go, in all kinds of terrain and weather. It doubles as my avitar. Mount the GPSr on the handlebar and I'm off & running. Thirty to thirty-five MPG for a 13 year-old bike (with a 30 year-old engine design) isn't to bad either. We also have a 1986 Nissan King Cab 4x4, just in case. Keep on Caching - Kewaneh

I don't make a habit of using my GPSr for navigation on a vehicle but I do use it when the fog gets bad. I've never had a fog related problem with it and have found that I can rely on it to tell me where I am when I can't tell by looking out the window. It's especially helpful when nearing intersections - the map lets me know when I'm approaching one. Any errors that may have occured were not outside of the norm of the unit. I would suspect that a 200 foot error was due to only having four satellites locked, but I doubt that the fog attributed to any lack of, or loss of lock. In my part of the world (San Joaquin Valley, California) we have some of the worst fog in the world (from what I understand) called Tule Fog. It's a very common occurance in the winter nights, particularly in the rural areas, and visibility can easily be less than 50 feet. Sometimes much less, like a zero-visibility snowstorm. There are times when literally you can be lucky to see even one dash of the dashed center line on the road you're driving. If any kind of fog would mess with a GPSr, it would be this stuff, and I've yet to see a problem. - Kewaneh

A Trimble R8 with a TSC2 Controller. It's a bit bulky for Geocaching (can you say 'overkill'?), but with near millimeter precision, the ability to receive the new L2C satellite signals, on-the-fly data processing, and Bluetooth connections, it's absolutely amazing. It's my weapon of choice for work. For Geocaching and Benchmarking, my GPSr of choice is a Magellan Gold. Mine is nearly three years old and still going strong. ... but a good Sextant will never let you down either. - Kewaneh