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This happens all the time and nobody does anything about it. NGS doesn't have funds to send crews out for this stuff. The "right" way is for a local surveyor to go through the NGS official RESET process to preserve a related elevation on a nearby new mark. That takes time $$ and knowledge that isn't going to happen very often. NGS officially says you should send in a destroyed disk, but that doesn't happen often either. Lots of people have souvenirs. We just hope they don't end up on eBay to encourage people to grab ones that weren't already destroyed. And then there is the upcoming redefinition of elevation NATRF2022 that should be released by 2025, after which all new work should use that, with GPS corrected for gravity variations, instead of physical disks. So the old disks will only be of use for finishing work in progress or checking historical work. Don't think your past recovery reports have been in vain. Many of the old disks were used to check whether the new datum was coming out consistent, via the GPSonBM program, so knowing which markers were still there helped guide the collection of the check data.

Currently I do chose the categories I list here by my own submissions waiting for over a week. I do not want to let someone else's submission sit there for too long, so this reveals mostly categories where I am active in posting myself. This time I have identified three more. They are all more global than the last one. and not really difficult. So there is no reasson to limit the candidates. Except for the usual stuff, of course. People who constantly try to ignore category requirements and/or always try to get away with the least possible effort will not become good officers. I believe that is fact, not opinion. Let's start with the easist one of them: Hydroelectric Power Stations. Things to look for: We are looking for the site where the generators are, not dams or lakes. The picture requirements ask for pictures of the machine house and the water supply. If possible. There are stations where one or the other are underground. We try to welcome these as well, but then we expect that the submission adapted to the special situation and impossible requirements are not just dropped without any replacement. Special cases need special quality. They can be abandoned, but there must be recognizable relics. And here Hydroelectric means: Water + Gravity = Electricity. No hot water, geothermal energy is not covered by this category. Who's interested?

Thanks for posting that, Ernmark. I'm gonna try that Android App. Though I don't plan on going back to the US anytime soon, I'm hoping it may be of some use with Border Monuments in the future. And while we're at it here are my most used Canadian Benchmark URLs: Passive Control Networks - Canada wide map of all Canadian Benchmarks. Lots of other tools, options and links on this page. Gravity Network - Canadian Gravity Network stations PROVINCIAL NETWORKS - Portal to all provincial networks within Canada Alberta Geodetic Control Unit - pointer to Alberta benchmarks and survey markers of all types. Lotsa stuff to wade through here, but INVALUABLE in discovering thousands of markers not catalogued anywhere else. SPIN - Alberta Spatial Information Network - land titles data products, registered survey plans, township images, survey control markers Geodiscover Alberta - The essential Alberta map. Instructions on how to use are in a pane on the left. MASCOT Home - British Columbia's portal to BC survey markers, including Canadian Benchmarks. International Boundary Report - For the more adventurous Benchmark Hunters, a very interesting 1937 Report by the International Boundary Commission. It includes information on boundary monuments, as well as information on now obscure Benchmarks related to border monuments. Other than by serendipity, few would likely find many of these benchmarks without the aid of this book.

bugcrowd2022_36 Category Name Waymarks Visited Birdwatching Locations 4 Histoires de France (French historical markers) 1 Vortexes, Mystery Spots, and Gravity Hills 1 Off-Leash Dog Areas 1 Washington Historical Markers 1 Vortexes, Mystery Spots, and Gravity Hills is my waymark and when I try to view it, I get this message: Please login with valid credenitals: Username: Password: However, I am able to edit it. I have tried to delete the visits, I am unable to remove them. bugcrowd2022_36 Visits

NGS is working on an update to the vertical datum. Just as NGVD29 was replaced by NAVD88 and NAD27 replaced by NAD83 when much better data became available, now there will be new horizontal and vertical datums labeled NAPGD2022, but unfortunately delayed somewhat beyond that year by funding and COVID. When the new vertical datum is released, elevations will change by some amount from the NAVD88 datum values. It has been found that NAVD has about a meter of tilt across the country. Three feet in 3000 miles isn't too bad, but they can now do better. Most importantly, as we know bench marks tend to go away and you are lucky if 1/4 of them are left in your area. The 2022 vertical values will be defined as what is measured by GPS (GNSS?) plus a geoid value, so that projects are no longer dependent on having a physical mark nearby. We have seen a series of geoid updates to better model the gravity, but those "hybrid" geoids still hold the old NAVD88 elevations on the marks in the data base, and only provide more accurate interpolation between those points. The 2022 datum will change all elevations to be more self-consistent across the country, using the best new geoid model they can make without depending just on old leveled benchmark values. For this they have been working on the GRAV-D project to get aerial measurement of gravity across the country and some gravity measurements on the ground. NGS needs a tool to allow people to convert NAVD88 elevations they have to good estimates of 2022 elevations. To check and refine the conversion model, they are using comparisons of GPS measurements versus NAVD88 values on good bench marks. Most of this data is being submitted by state DOT or DNR agencies, with some from various other sources including individual surveyors or researchers with the required equipment, submitted as OPUS Share data (see map of submissions). Look up the GPSonBM project for details. I hope that explanation helps, and is sufficiently clear. DaveD can correct me if I misstated anything.

Dayton-Harris Gravity Disk Death Valley https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=GS0206

An open letter to Groundspeak administration: In the early 2000s a fledgling company, looking to expand its product line and thereby increase its customer base, imported a database of benchmarks that its customers could search and log from what is now know as NOAA. Over time the customers provided the necessary additional products (geocaches) to allow the company to survive and grow. To Groundspeak’s administration benchmarks became a forgotten backwater as evidenced by the benign neglect that the platform has endured for many years. Now this same administration wants to remove benchmarking and its remarkable compendium of logs and photographs, one of the elements that helped the company survive its infancy. Let’s examine the reasons that they have stated for this wrongheaded decision: The game is global and benchmarking is a United States pursuit. As others have stated, there are multiple geocaching pursuits that are all or nearly all US based among them the APE cache(s), the original stash plaque and various events limited to HQ and environs. So “globalism” does not make a compelling argument. Very few people engage in benchmarking so it doesn’t make economic sense to support it. This should be entered in a dictionary of “self fulfilling prophesies” as a quintessential example. I can think of no other segment of the Groundspeak universe that has received as little marketing and promotion as benchmarking. For quite some time you have had to stumble over it to find it compared to everything else. I know some people that primarily looked for benchmarks during the early part of the pandemic before much was known about the virus’s survivability on caches or other surfaces. Imagine what a boost it would have been to the hobby if Groundspeak had actively promoted benchmarking during that time. The code is old and upkeep is costly. Who’s fault is that? I am certain that the code running the geocache part of the platform is not from 2002. I’ve lived through outages (that I fully understand) caused by multiple upgrades over the years. The ONLY reason we are at this juncture is because administration decided not to spend the money years ago to do the maintenance needed on the benchmarking side. Now we, the paying customer, will pay the price by losing part of the game. Shame on you, Groundspeak, for failing to spend our money wisely. Speaking of spending our money wisely, now I turn to the excuse that the benchmarking code is getting in the way of new and exciting projects. I have no idea what those are because no one has shared that information. Unlike some members of this board I have no faith, based on the last decade of “innovations” some of which have gone by the wayside, that I and many like me will find them a good trade for removing benchmarking. Imagine if the money lost on some of those “innovations” had been directed at upgrading the benchmarking code. Groundspeak likes to talk about the “Language of Location” The language of location in the United States was established by the survey crews that gradually established the network of horizontal and vertical locations that enabled the building of roads and bridges, homes and factories, canals and railroads, cities and towns that made the USA. This was often backbreaking work in inhospitable conditions. It required axe work and lugging surveying chains as often as using precision instruments like theodolites. These precisely measured locations (whether horizontal, vertical or both) are still used today, even in the era of the Global Positioning System, to make sure that water doesn’t flow in the wrong direction, houses aren’t built on the wrong property and for many other reasons. As benchmarkers we have helped find missing markers and reported those that have been destroyed. As august a presence as Dave Doyle, retired NGS chief geodetic surveyor, recently said in the Benchmarking forum “Many thanks to so many who have posted great pictures and hand-held positions that I've been able to harvest and improve the quality of tens of thousands of stations in the National Spatial Reference System.” Perhaps if Jeremy, Bryan, Elias or one of the more public facing lackeys had ever made the hike to station Buttermilk, (https://www.geocaching.com/mark/details.aspx?PID=LX4113) the oldest surviving triangulation station in the country, they might have experienced the same sense of awe and history that I did when I visited that site. But none of them did, despite traveling to many parts of the USA to promote Groundspeak and its activities (and, for many of the lackeys, to geocache.) They might have learned with a little research that Ferdinand Hassler, the first superindentent of the US Coast Survey, spent two weeks in June of 1833 with his wagon of instruments and his survey team setting this mark. I’ve been to the Original Stash Plaque and the Tunnel of Light APE cache. They are certainly historical but not remotely in the same class as finding Station Buttermilk. The only things that have come close are finding TU2116 (https://www.geocaching.com/mark/details.aspx?PID=TU2116) a benchmark placed by the Republic of Hawaii (check your history boys and girls) in 1896 and GS0206 (https://www.geocaching.com/mark/details.aspx?PID=GS0206) a gravity station in Death Valley (there are as many types of “benchmarks” as there are geocaches, some as rare as webcams.) None of the solutions that have been proposed on this forum have the same functionality as the current system. Waymaking does not have the database, NGS DataExplorer does not have the photographs and NOAA certaily does not want recovery notes every few months on the more popular and easily found stations. Finally, eliminating benchmarking from this site would be the equivilant of burning down a unique and valuable library, a library that has played a far more valuable civic role than any other aspect of this hobby. The current situation of low usage and old code is primarliy the result of decisions, conscious or subconscious, made by Groundspeak’s administration over the years. These same people can fix the problem by spending the money to revamp the system and market the activity. To rather spend money to move the hobby further from its roots toward more instant gratification may result in short term gain but long term loss. I urge reconsideration of this decision. Benchmarking is this community’s connection to the history of geolocation. Let’s strengthen that connection, not lose it. Michaelcycle and Susancycle

Back in 2016 I attended an event hosted by The Maryland Society of Surveyors that was a presentation/Q&A session about benchmarks. I learned a lot about benchmarks, but the most important thing that stuck out to me was how the NGS (National Geodetic Survey) was using the information submitted by Geocachers to help update their database. To see this in action consider one of the benchmarks I found recently: HV0059. The originally imported datasheet on Geocaching list scaled coordinates of 38 46 29 (N) 076 04 35 (W). Scaled coordinates means before the days of GPS someone tried to line the description up with a map and made their best guess. Now compare that to the current datasheet. It has handheld coordinates of 38 46 29.00 (N) 076 04 36.54 (W) and look at who made the last recovery note. This is common when looking at the updated datasheets. Just like CITO this is a way Geocaching has given back to the community, and soon it will be gone. NGS still has their own program for citizen submission, but it is hard to imagine they will obtain the same amount of information without benchmark logging integrated into the Geocaching site. Perhaps it is an extreme long shot, but have you even contacted NGS for the potential for some amount of funding or at the very least for their comments on this decision? You say their is no one to perform maintenance on them. Did you try to find volunteers like there are for reviewing Geocaches? You say they are only available in the US. This does not have to be so! The UK has trigpoints you could add. And look how cool they are. It was a choice not to try to extend the concept to other countries. You say only few people log them, but they seem almost intentionally hidden. How were new members to even learn they existed? It is so disheartening to be powerless to a constant barrage of short sighted money based decisions (including but not just at Geocaching) to make the internet worse than it was or could be. The memories I have from benchmarks are up there with the rest of the memories from Geocaching. The time I hung off the side of a bridge with one arm to get a picture without being in traffic. The one and only time I was able to find an azimuth disk. Taking the time to look for all the reference marks. And there was so much I was still looking forward to. Trying to get the rare gravity and magnetic types of disks. Trying to convince this building to let me on their roof. Something to log on mountains where Geocaches aren't allowed to be placed. At least I never bought a metal detector like I had been planning...

In the Interesting, Yet Not Permanent category I submit the following: Much of the interest here lies in the snowman's gravity defying properties. However, he could never be considered permanent, however much we might wish him to be. While he is a couple of months old, he once was much more robust. The weather of the past couple of weeks has trimmed him down considerably and he is due to do a face plant in the ground any moment now.

Ran a query on my database (which is valid and complete as of NGS's archive at the beginning of this month (Aug 1st), and here is an interesting breakdown of the number of station types. The 'CDE' column is the 1 or 2 letter/digit marker type as seen on datasheets. The 'IN?' is wither it's a Intersection or not (1 - yes, 0 - no), and the # is the number of datasheets that list that as a marker type: CDE IN? # MARKER TYPE DESCRIPTION J 0 2 Earthenware jug Y 0 3 Drill hole in brick 23 1 3 VOR antenna 24 1 3 REN antenna 69 1 4 Regulatory sign 95 1 4 Rooftop blockhouse DK 0 5 Gravity reference mark disk DP 0 5 Base line pier disk 68 1 9 Commercial sign 05 1 11 Rock awash 28 1 11 LORAN mast 88 1 13 Observatory dome 93 1 13 Microwave antenna on building 17 1 17 Flag tower E 0 18 Earthenware pot L 0 22 Gravity plug 74 1 28 Large cross 18 1 30 Signal mast 84 1 39 Lightning rod 92 1 44 Antenna on roof 25 1 45 Radar antenna 26 1 46 Spherical radome 94 1 51 Rooftop ventilator 64 1 57 Silo DW 0 60 NOS hydrographic survey disk DA 0 61 Astro pier disk 27 1 63 Radio range mast 01 1 71 Lone tree M 0 76 Ammo shell casing 56 1 78 Skeleton tower 70 1 84 Monument 67 1 85 Oil derrick 12 1 88 Dolphin T 0 95 Chiseled triangle 11 1 96 Piling 58 1 150 Control tower G 0 150 Glass bottle K 0 156 Clay tile pipe 54 1 169 Water tower 02 1 176 Conspicuous rock 75 1 195 Belfry 41 1 223 Antenna mast DM 0 231 Magnetic station disk 82 1 242 Finial O 0 252 Chiseled circle DG 0 256 Gravity station disk 04 1 272 Rock pinnacle U 0 333 Concrete post (without other marks) 66 1 349 Windmill 89 1 357 Spire 61 1 363 Pole 83 1 387 Flagstaff DQ 0 416 Calibration base line disk 73 1 462 Lookout house 71 1 478 Boundary monument 87 1 542 Dome 65 1 560 Grain elevator 81 1 598 Gable W 0 606 Unmonumented 44 1 634 Microwave mast 72 1 636 Cairn V 0 670 Stone monument 13 1 698 Lighthouse 16 1 701 Daybeacon 21 1 724 Airport beacon 03 1 745 Mountain peak DU 0 780 Boundary marker 45 1 823 Microwave tower 91 1 824 Church cross 62 1 887 Flagpole 15 1 958 Range marker 43 1 1081 Radio/TV tower 86 1 1090 Cupola 22 1 1147 Airway beacon 52 1 1263 Standpipe tank 85 1 1321 Chimney A 0 1411 Aluminum marker other than a disk included elsewhere in table 55 1 1545 Tower C 0 1601 Cap of cap-and-bolt pair S 0 2036 Spike X 0 2107 Chiseled cross DT 0 2192 Topographic station disk 51 1 2626 Tank 57 1 2719 Lookout tower H 0 2806 Drill hole 90 1 3255 Church spire N 0 3469 Nail 63 1 3479 Stack 14 1 3916 Navigation light 42 1 3980 Radio/TV mast DJ 0 4356 Tidal station disk Q 0 5266 Chiseled square B 0 7676 Bolt DO 0 7827 Disk not specified (see description) R 0 8413 Rivet P 0 8743 Pipe cap 53 1 9769 Elevated tank DZ 0 10900 Azimuth mark disk F 0 17623 Flange-encased rod DH 0 18746 Horizontal control disk DE 0 19119 Traverse station disk Z 0 20695 See description DV 0 24159 Vertical control disk I 0 33163 Metal rod DR 0 33680 Reference mark disk DS 0 78967 Triangulation station disk DD 0 158147 Survey disk (other agency) DB 0 328935 Bench mark disk Not listed above are the just under 44k datasheets that have no marker type specified.

What "kills" most caches are water and sunlight and not being closed. An easy to close waterproof container, placed in a "sheltered from the elements" location and not in direct contact with the ground is your best bet for longevity. Any placement that gravity can affect benefits from a tether. Hiding well off the beaten path where possible is the best defense against muggle discovery. No guarantee, but higher terrain placements increase the chances that finds will be made by folks who are more likely to actually close the container properly. As noted: ammo cans, plastic boxes with sturdy gaskets and latches, and lock& locks are some of the best containers. I've also had pretty good luck with lock&locks loosely wrapped up in piece of plastic tarp: the tarp sheds water and snow and keeps out the sunlight while the lock and lock keeps stuff dry. Most folks can open and close a lock&lock and rewrap a piece of tarp...

By the most commonly understood definition, this shouldn't be acceptable in Preserved Machines on Public Display. Machine, from Wordnik: "A device consisting of fixed and moving parts that modifies mechanical energy and transmits it in a more useful form." Yet, by another definition, from the same source, it could, while broadly interpreting said definition, become acceptable, "A system or device, such as a computer, that performs or assists in the performance of a human task" , as it assists in performing what would otherwise be a human task, that of providing water to steam powered locomotives. A pretty loose interpretation of the general understanding of the word "machine", I'll admit, but potentially applicable, nonetheless. Also, strictly speaking, this isn't a "water pump", as the pumping of the water occurs underground, likely accomplished by an electrically driven pump. This is simply an elaborate spigot, hydrant, outlet, etc. - can't think of a proper definition for it. Keith Edit: Despite the fact that I once Waymarked a STOP Sign, one of our legendary Waymarkers (which one I no longer recall) once stated that: "Not everything needs to be Waymarked". Edit #2 - Looking once again at the photo, it appears that the spigot, hydrant, outlet, etc. stands beside what may well be a water tower, making this a gravity-fed spigot, hydrant, outlet, etc., and the water tower Waymarkable.

I have again been trying to understand what elevation means. Probably not one person in 100,000, and very few professional surveyors, understand the answers to these questions: What does Orthometric mean? Why wouldn't a large loop of perfect optical leveling measurements come back to the same elevation at the starting point? Dynamic height? What is the geoid? Why isn't gravitational force the same everywhere on the geoid? How do you find the geoid under a land mass? Bouguer plate? What approximations are made in the definition of NAVD88? Does water flow uphill some places? (That comes back to the definition and measurement of "uphill.") I have _Physical Geodesy_ by Hoffman-Wellenhof and Moritz. I can almost read it with what college calculus and vector math I remember, but they give almost no examples so I'm not always sure I know the implications. I have Elementary Surveying by Wolf and Ghilani, but their chapter on the subject is a cut and paste of some relevant material that is not complete enough for continuity. A brief search has not found the ideal tutorial, although I did find some helpful stuff including a powerpoint by someone at NGS. Maybe what I'm looking for is a college sophomore level explanation of a graduate level subject. So does anybody have any recommendations?

Two years ago I found a benchmark in Great Falls Montana that had a Marker Type listed as "gravity station disk" The disk read "International Gravity Station University of Wisconsin" as was stamped "Great Falls B". So what is an International Gravity Station? Didn't notice any changes in gravity in the area []

Hello! Our family has just started geocaching, we got equipment for Christmas and have already had a good time trying to find some local caches. We got the GeomateJr and it has worked pretty well thus far, but I'm wondering if I can augment our experience with my phone. I have a TMobile Gravity T phone like this one: http://www.t-mobile.com/shop/Phones/cell-phone-detail.aspx?cell-phone=Samsung-Gravity-T I don't generally have a data plan, but right now I do have data access that I got for free for a month. I've never had a phone with data, so I'm pretty inexperienced with it, plus it doesn't seem all that intuitive or easy to use. Would I be able to geocache with this phone even after my free data month goes away? If so, what would I need to install? Any help would be appreciated very much! Thank you! - Kirk

Please bring back the "Wear Your Best Suit" photo goal. I've just completed the goal and now I see it has just been archived. Why? Just because someone thinks its not daring or death defying enough?? As my log stated, "Everyone likes getting dressed up now and then, and these days we don't seem to get enough opportunities to put our glad rags on. " This is what photo goals used to be about, just doing something and having fun, didn't have to be an ‘eye rolling’ thing or a ‘Dare You’ thing. Getting really dressed up IS doing something, especially if it’s for an important occasion. The Past Activity page makes interesting reading, so many Declines then Approves then Declines again, for the same goal, it looks like no-one knows what they're doing! Wear Your Best Suit was one of those, approved and now gone, PLEASE bring it back for good!

I bought a Samsung Gravity 3 yesterday. Is there a compatible geocaching app for it? I've looked and looked, but I'm so new, that even if I found a compatible app (and recognized it as compatible in the first place), I wouldn't know how to get it to my phone. Geobeagle (which I have heard good things about) supports the Samsung Gravity 2. But the 2 wasn't an option when I was shopping. I figured the 3 was just a newer version. The tutorials are vague (at best), assuming that app buyers know how to download and install the app in the first place. Is If there isn't, I have 30 days to trade it for something that will work. Any help is appreciated! Diane

I just recently bought a Samsung Gravity Touch. And was wondering if anyone knows if there is an app or widget for these phones. I was just curious. Thank you.

Good evening fellow cachers! So a friend and I may be taking a mini-detour to SLC on our road trip to Denver in a few weeks and I was wondering if any locals know anything about the gravity hill near the capitol? Apparently, (on this hill) when you put your car in neutral it will appear to roll uphill due to an optical illusion from the surrounding scenery. If anyone knows the exact location of this place (coordinates would be great), I would greatly appreciate it if you could post them here. I've googled it, but the location descriptions are kind of vague only indicating that it is somewhere near the capitol. I know it kind of sounds like a silly request, but it's something I heard about when I was a kid and always thought it sounded like an interesting place to visit. And of course, any suggestions for good nearby caches would be appreciated as well Cheers!

If you hold a normal compass (mine is an old Boy Scout compass) flat the arrow points to Magnetic North. You then rotate the base to point towards your waypoint to set the bearing. All works fine, but if you tilt the compass it will display corrupted information. The same could be true for GPSr units, however... On my GPSr I display the heading arrow and the actual bearing to the next waypoint. The bearing is determined by the GPS signal, but the heading is determined by either motion (>1.5 mph) or, if no motion, magnetometers. Just like my BSA compass, tilting the GPSr will corrupt the heading unless corrected. Older GPSr used a bubble level to fix the compass’ orientation but now most GPSrs use accelerometers. There are three accelerometers that are used to orient GPSrs by determining which way is down (center of the earth) by measuring the acceleration forces in 3-space (XYZ). Gravity is an acceleration force. Magnetometers are constantly changing as the GPSr moves through local lines of magnetic flux. Accelerometers are calibrated once (unless they become corrupted) so the GPSr knows how it is oriented. If tilted the GPSr can mathematically reorient itself to find the center of the earth. It should be noted, magnetic compasses don’t necessarily point to Magnetic North. They align themselves to the local lines of force which generally point to Magnetic North. These lines of force are subject to local disturbances that may bend them and throw off the compass needle.

The planned service life of WISA Woodsat is approximately 2 years but if all goes well, it might be significantly longer. The time on orbit is estimated to be 7-10 years. During that time the velocity will slow down so much that gravity will start pulling the satellite from the orbit. As WISA Woodsat is small and made of wood instead of e.g. aluminum, it will turn into gas (it will not burn due to the lack of oxygen).

I am pleased to announce that we have three winners of the Survey Mark Quiz. First place goes to “Bill93”, second place to “m&h”, and third place to “billwallace”. Congrats to all! More good news, everyone passed and the average grade was 81.25%. No one got 100% however. I did an analysis to see which questions were answered incorrectly most often. Question #1 was the worst, followed by questions #23 and #27. There were 16 questions that everyone got correct. Here are the correct answers (at least my opinion) and some brief comments. 1. In which time frame were the first survey disks set in the U.S. by any agency? A. 1810-1819, B, 1850-1859, *C. 1870-1879, D. 1900-1909. The key words in the question are “..by any agency?” Verplanck Colvin set survey disks in the Adirondack Mountains during the 1870’s as the Superintendent of the Adirondack Survey (New York State agency). In fact, the earliest USC&GS disks (1900) bear a striking resemblance to Colvin’s disks. See page 9 of my paper on survey marks at: http://www.ngs.noaa.gov/web/about_ngs/hist...ey_Mark_Art.pdf and: http://www.colvincrew.org/verplanck-colvin . 2. What is the definition of a bench mark? A. Any point in the Geocaching or National Geodetic Survey databases, B. Any survey disk, *C. A mark with a known elevation above or below a certain datum, D. A brand of booze. Glad to report that no one selected “D” - everyone got this one correct!! 3. The Bilby Tower was first used in the year: A. 1870, B. 1900, C. 1917, *D. 1927. It was designed by Jasper Bilby in 1926 based on the common windmill towers, and first used in 1927. The last tower built by this agency was built in 1984. For a photo of one of the first towers built, see: http://usasearch.gov/search?v%3aproject=fi...amp;rpaid=& 4. A “Base Line” is: A. A line between two survey points that is carefully measured for use on controlling the scale of triangulation, B. A line between two survey points that is carefully measured and used to calibrate electronic distance measuring instruments, *C. Both of the above, D. Neither of the above. 5. Which if the following is not a standard height for a Bilby Tower: A. 37, B. 50, *C. 63, D. 103. The standard heights were 24, 37, 50, 64, 77, 90, 103, 116, and 129 (discontinued). The most common heights were 77 and 90 feet because these heights would get above most trees and also provide enough height to help compensate for the curvature of the earth. These heights were to the top of the inner tower – the height of the instrument. The light plate at the very top of the outer tower was 10 feet higher. Note, the tower leg sections were 13 feet, 8.5 inches long so that the heights could be varied at the above intervals depending on the reconnaissance work done ahead of time by a reconnaissance party. The leg sections overlapped and were joined by two bolts. The section length, this overlap, and rounding to the nearest foot caused the height differences to not be exactly 13 feet and caused the 14 foot difference between the 50 foot tower height and the 64 foot height. The 1965 version of the manual for Bilby Towers is on-line at: http://docs.lib.noaa.gov/rescue/cgs_specpu...5U352no62-3.PDF . This document contains excellent photographs and drawings. 6. Which of the following were used as survey marks by the USC&GS: A. Bottles, B. Wooden stakes, C. Nails, *D. All of the above. 7. Which of the following types of USC&GS survey disks had arrows on them? A. Reference marks, B. Azimuth marks, C. Gravity reference marks, *D. All of the above. 8. Which of the following were used to measure distances by the USC&GS/NGS? A. A chain, B. A rod in an ice bath, C. A laser, *D. All of the above. 9. The first survey disks used by the USC&GS were: A. Flat on top, *B. “Cup” shaped, C. Convex on top, D. None of the above. 10. A tower such as a church spire, radio mast, or water tank which has been surveyed is called a: A. Bench mark, B. Survey mark, *C. Intersection station, D. None of the above. I guess this is one of my “pet peeves” – when people refer to “Intersection Stations” as “Bench Marks”. 11. Most USC&GS survey disks were set between the years: A. 1807 – Present B. 1880 – 1970 *C. 1900 – 1970 D. 1910 – present. 12. National Ocean Survey (later National Ocean Service) disks were set to mark: A. Tidal bench marks, B. Third-order horizontal points for hydrographic surveys, C. Airport surveys, *D. All of the above. 13. Reference marks are generally within ______ meters of the triangulation station. A. 10, B. 20, *C. 30, D. 40. Because 30 meters (or 100 feet) is the length of many measuring tapes. 14. USC&GS or NGS survey disks have been made of: A. Brass/bronze, B. Iron/steel, C. Aluminum, *D. All of the above. 15. A USC&GS disk with a circle in the center could mark a: A. Topographic Station, B. Hydrographic Station, C. Bench Mark, *D. All of the above. 16. The rarest USC&GS disk is probably the: A. Hexangle shaped Gravity disk, B. “Cup” shaped triangulation station disk, C. Magnetic station disk with 6-pointed star, *D. Hexangle shaped Gravity reference mark disk. Our current NGS “gravity guy” told me he has only ever seen 1 or 2 of these. I have never seen even one. 17. Which of these is usually the only one with a horizontal position? A. MAGNETIC STATION, B. GRAVITY STATION, C. BENCH MARK, *D. TOPOGRAPHIC STATION. Topographic Stations have third-order horizontal positions, formerly used to control shoreline mapping. 18. Which of these types of disks may have an underground mark beneath it? A. TRIANGULATION STATION, B. REFENCE MARK, C. AZIMUTH MARK, *D. All of the above During the 1970’s it was common practice to set underground marks at Azimuth Marks (because the Azimuth Marks were positioned then). Underground marks at Reference Marks were rare but were set at one point in time. 19. Survey disks are set: A. Above ground level, B. Below ground level, C. Flush with the ground, *D. All of the above. 20. Which of the following types of disks do not have a blank spot for stamping the elevation? A. BENCH MARK with 3 crossed slashes, B. TRAVERSE STATION, C. USC&GS AND STATE SURVEY, *D. GRAVITY STATION. 21. Which of the following symbols used in the center of a disk were not used on a BENCH MARK disk? A. Slash, B . Circle, C. Three crossed slashes, *D. Triangle. 22. Which of these USC&GS disks did the NGS HORIZONTAL CONTROL MARK not replace? A. TOPOGRAPHIC STATION, B. HYDROGRAPHIC STATION, *C. GRAVITY STATION, D. TRAVERSE STATION. The Topo. Sta., the Hydro. Sta. and the Traverse Stations were all set and surveyed to provide horizontal positions. 23. Which of these following disk symbols were used to mark horizontal control points? A. Triangle, B. Circle, C. Cross, *D. All of the above. USC&GS Topographic Station disks and Hydrographic Station disks have circles in the center. “Topo” disks were used for horizontal control for shoreline mapping and airport surveys, and “Hydro” disks were used for horizontal control of hydrographic surveys. These surveys were mainly third-order, and positioned from higher order triangulation stations. NOS disks used for horizontal control have a “+” in the center. 24. When searching for a survey mark on a hill top, look for: A. Highest point, B. Point with best visibility around the horizon, C. Place where you would have set the mark, *D. All of the above. Hilltop points would almost always be triangulation stations (its too time consuming to level to the top of a tall hill or mountain). All three factors apply. 25. When looking for a bench mark (vertical point), consider: A. Mark spacing along the level line, B. Exposed bedrock, C. Clues in the Description, *D. All of the above. 26. Which of the following is not true about Reference Marks? A. Disks have arrows pointing to the Triangulation Station, B. Marks usually less than 100 feet from the Station, *C. Always higher than the Station, D. Station Description contains the distance and direction from the Station to the RMs. 27. Which of the following usually do not have an accurate horizontal position? A. GRAVITY STATION, B. MAGNETIC STATION, C. BENCH MARK, *D. All of the above. This is the third of the most commonly missed questions. Gravity Stations, when originally set, usually have only gravity information, Magnetic Stations have magnetic information and Bench Marks have elevations. Later, any of these might be surveyed again as part of a triangulation project and given an accurate horizontal position. 28. The most important factor in a close-up photograph of a survey mark: A., No debris covering mark, *B. All stamping is clear and legible, C. Even lighting, D. Disk fills most of photo. 29. Which of the following is not needed when recovering a survey mark? A. Station Description, *B. Hammer, C. Tape measure, D. Magnetic compass. A hammer is sometimes useful, but is the least essential of the four. 30. Which of the following is not a parameter for setting a concrete mark: A. Four feet deep, B. Twelve inches in diameter, *C. Rebar placed in concrete, D. Collar or form used around top portion of mark. We stopped putting magnetic materials in monuments many years ago. 31. Survey towers were made of: A. Steel, B. Wood, C. Aluminum, *D. All of the above. 32. Which of the following can be used to measure horizontal angles: A. Transit, B. Sextant, C. Theodolite, *D. All of the above. A sextant can be turned 90 degrees (flat with the horizon) and used to measure horizontal angles. In fact, fixes from two horizontal sextant angles were the method used for many years to position hydrographic survey launches. Angles were turned between a series of marked points (signals) along the shoreline. 33. Tools used to dig a hole for a concrete mark include: A. Auger, B. Post hole digger, C. Sharp-shooter shovel, *D. All of the above. 34. The back of a survey disk might contain: A. A Stem for setting in a drill hole in bedrock or a large structure, B. A Tube for mounting on a buried rod, C. A Collar for mounting on a pipe, *D. All of the above. 35. Which type of disk came in two shapes? A. MAGNETIC STATION, *B. GRAVITY STATION, C. HYDROGRAPHIC STATION, D. None of the above. 36. During the 1950’s and 1960’s, the number of disks set at a Triangulation Station was usually: A. 3, B. 4, *C. 5, D. 6. Station disk, underground station disk, RM1 disk, RM2 disk, and Azimuth Mark disk. 37. For many years, the specified distance range from the Triangulation Station to the Azimuth Mark was: A. 30 meters to 3 miles, B. 100 meters to 3 miles, *C. 1/4 mile to 2 miles, D. None of the above. 38. USC&GS disks were phased out of usage when NOAA was formed in: *A. 1970, B. 1971, C. 1972, D. None of the above. 39. The NGS disk that did not replace a USC&GS disk: A. HORIZONTAL CONTROL MARK, B. VERTICAL CONTROL MARK, C. GRAVITY MARK, *D. CALIBRATION BASE LINE. 40. The following types of aluminum logo caps were made (collar and lid to protect stainless steel rod marks): A. Vertical Control Mark, B. Geodetic control mark, C. Tidal Bench Mark, *D. All of the above. All three were made and we still use “B” and C”. Three winners - please email me your mailing addresses and I will mail your prizes. T-shirts, like the one awarded for first place, are available for sale by the U.S. Coast & Geodetic Survey Heritage Society. Let me know if you are interested. T-shirt graphics at: BM on front ( ) and the un-official USC&GS logo of an Eagle with a sextant on the back ( ). GeorgeL NGS

Can someone explain a gravity station in brief non-surveyer's terms? I understand a triangulation station (horizonal) and a benchmark (verticle). What's the purpose of a gravity station? I'm sure it has something to do with measuring gravity . What does gravity have to do with mapping and surveying?

I'd like to propose new category based on my personal interest in the topic. Comments and suggestions appreciated. Description: The goal of this category is to waymark works of Space Art that are on permanent public display around the world. Expanded Description: Space Art is the genre of modern artistic expression emerging from knowledge and ideas associated with outer space, both as a source of inspiration and as a means for visualizing and promoting space travel. Like other genres of artistic creation, Space Art has many facets and encompasses realism, impressionism, hardware, sculpture, abstract imagery, even zoological art. In general, works of Space Art strive to visualize the wonders of the Universe. Though artists have been making art with astronomical elements for a long time, the genre of Space Art itself is still in its infancy, having begun only when humanity gained the ability to look off our world and artistically depicted what we see out there. Whatever the stylistic path, the artist is generally attempting to communicate ideas somehow related to space, often including an appreciation of the infinite variety, wonder, and vastness of the Universe which surrounds us. There are several sub-genres of Space Art, each with their own unique characteristics: - Descriptive Realism (“Rocks and Balls”) - it is an aspect of Space Art whose primary emphasis is to show a viewer a scientifically accurate visual depiction of alien places in the Cosmos. - Cosmic Impressionism (“Swirly Art”) - like works done in the impressionist era, Space Art works in the Cosmic Impressionism style use color and form to give a viewer the artist’s impression of the image subject matter without trying to be technically accurate, highly detailed, or adhering to known scientific principles; despite being more loose, the subject matter is still clearly inspired by space. - Hardware Art (“Nuts and Bolts”) - it is usually similar to Descriptive Realism but focuses on the detailed depiction of the hardware of spaceships, probes, and equipment being used in a space setting. - Cosmic Zoology - Though the question of other life in the universe has yet to be answered, artists can speculate about it and imagine the possibilities; Cosmic Zoology is the depiction of extraterrestrial life in extraterrestrial settings. - Astronomical Photography - it is a form of extra-terrestrial photography, usually via space probes, where a photo is deliberately framed to place esthetic value over scientific value. - Space Sculpture - Works of Space Sculpture are more difficult to recognize as such as they are usually more symbolic or abstract in nature, like a rocket shape, stained glass windows representing stellar objects, or a sculptured work designed specifically for zero gravity display. However, the prime inspiration for three dimensional works of Space Art is the same as other sub-genres, space itself. The premier organization and only guild in the world dedicated to the creation of Space Art is the International Association of Astronomical Artists (IAAA). Sources: iaaa.org; wikipedia.ord Instructions for Posting a Space Art Waymark: We are interested in works of Space Art that are on permanent public display. Please post at least two original photographs of Space Art. In the Long Description section provide at least one paragraph of text about the Space Art that you are Waymarking. Name your Space Art waymark as: Space Art Name - City, State, Country Bilingual and multilingual Space Art waymarks are accepted and encouraged, but one of the languages must be English.

I, too have heard that story and told it more than once. I remember as a kid in the 60's seeing the TV commercials for the "Space Pen" that would write upside down or in weightlessness!! Wow!! But, this, from Wikipedia's entry on "Writing in Space": <Quote> "A common misconception states that, faced with the fact that ball-point pens would not write in zero-gravity, the Fisher Space Pen was devised as the result of millions of dollars of unnecessary spending on NASA's part when the Soviet Union took the simpler and cheaper route of just using pencils. In reality, the space pen was independently developed by Paul C. Fisher, founder of the Fisher Pen Company, with $1 million of his own funds.[1][2][3][4] NASA tested and approved the pen for space use, then purchased 400 pens at $6 per pen.[5] The Soviet Union subsequently also purchased the space pen for its Soyuz spaceflights." </Quote>