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Welkom Geo-Gravity en Sus Antigoon. Ter info: ik heb jullie aankondiging ook gepost op het Geocaching.BE forum (link)

Hallo Belgische geocachers, Mijn naam is George Gravitalis. Ik ben een aangename belg met griekse roots. Sinds kort ben ik het Nederlands-Belgisch reviewer team komen versterken. Zoals mijn collega's reviewers stel ik mij vrijwillig ter beschikking van de geocache-community en zal ik mijn uiterste best doen om jullie geocaches op een zo goed mogelijke en snelle manier proberen te reviewen. Zoals verschillende onder jullie al zullen gemerkt hebben, en ik zelf ook, ben ik bereikbaar via volgende kanalen om op al jullie vragen te antwoorden. Twitter: @Geo_Gravity Mail: geo.0.gravity@gmail.com groetjes George

Hallo Nederlandse en Belgische geocachers, Mijn naam is George Gravitalis. Ik ben een aangename belg met griekse roots. Sinds kort ben ik het Nederlands-Belgisch reviewer team komen versterken. Zoals mijn collega's reviewers stel ik mij vrijwillig ter beschikking van de geocache-community en zal ik mijn uiterste best doen om jullie geocaches op een zo goed mogelijke en snelle manier proberen te reviewen. Zoals verschillende onder jullie al zullen gemerkt hebben, en ik zelf ook, ben ik bereikbaar via volgende kanalen om op al jullie vragen te antwoorden. Twitter: @Geo_Gravity Mail: geo.0.gravity@gmail.com groetjes George

Training was good, Frogfoot1 have a nice holiday. I'll make you proud. @Geo_Gravity geo.0.gravity@gmail.com

BOS, From the best I can research this out and avoid giving a Bibliography longer than the answer, Here is the Gist of what I could find. Prior to the take over in 1970, when NOAA and the NOS basically Swallowed the CG&S (Coast and Geodetic Survey, NGS basically ended their Geomagnetic program. Perhaps as late as 1973, as there are differing sources, the USGS took over the Bulk of that work. It would appear you found the website for USGS coverage, but it does not seem to treat the subject really well with respect to the history. Though it appears that the CGS was involved in taking geomagnetic readings as early as the late 1800's perhaps prior to the early 1900's, the bulk of the work appears to have gone on after World War II. The NOAA history of NGS seems to allude briefly to this Geomagnetic work in places, but even though electromagnetic observations are very important, it really turned out to be not as important to the study of Geodesy as Gravity and Other forms of physical observation and so they gave it to an Agency to whom it would be a better fit to their mission. As such, it is only touched on just briefly in the NGS History. I suppose you could redirect your study of this towards the actual instruments and methodologies, Perhaps some of the College based and private website will allude to the history of this work as well. For the worst part, A Government Career generally lasts only 30 years so the people who may have been players in the geomagnetic game at NGS have likely been long since retired. I would well imagine that the Bulk of them closer to the 35 years ago when the work there ended. That is a pretty cold trail. Best bet would be to see if a Historian at NOAA or NGS knows of or has read of history beyond that which seems to be currently available. As to your direct questions: >they don't seem to get replaced when destroyed. They really have little value beyond their Optically Derived Triangulation Data. Today's Models are GPS CORS and HARN. >What is their significance? They were places to specifically measure geomagnetic values at specific places in the country. This still happens but in different locations and is a real time network. There are also Satellite and aircraft derived observations as well. These stations are simply, Old School if you will. >Why were they set? To create a replicatable location from which data compiled over time could be compared. >How are they different from other marks? Well, They are similar in that they were often Optically Triangulated and so are part of the Horizontal survey network, they are different in that they served an additional duty in the Compiling of Geomagnetic Data. I would imagine that some scouting in a local area and knowledge of the local geological conditions in that given area helped determine the Net Value of a given location, before it was determined to be suitable for making this sort of observation. In other words, It is likely that not just any location is good enough, you have to find the best ones. >How often were they occupied or visited? The frequency may be determined and seeing if a filing was made on the datasheet. That would be the way to reverse engineer that answer anyway. >For how long at a time? Before real time observations became doable, Most any survey measurements ever made are meant to be productive so we, as observers, take only as long as it takes to get the information needed and verify (as in double check) it is as accurate as we can manage. I am unfamiliar with the specific equipment used in that era. This is really pretty specialized scientific work. >What equipment used Well Here is a site which may help with today's take on the question: http://www.gemsys.ca/Quantum/Scientific/Pr...39;s%20Fury.htm For some super in-depth information have a look at this site and prepare to spend some time reading. http://www.lund.irf.se/HeliosHome/geomag_magnetometers.html >What parameters measured? Again I think you may find that covered at this link: http://www.lund.irf.se/HeliosHome/geomag_magnetometers.html The USGS may also have outlined what data they collect and how they use it. Good Luck and enjoy! Klemmer, Thanks for the Link but we were talking Gravity in that discussion rather than Geomagnetics. But I think we can agree there is a lot to know about the world. In the news just today we learned that the Earthquake in the Indian Ocean on Dec 26, 2004, the one that caused Tsunami's has been observed to have altered Geodetic measurements reportedly by as much as a half inch globally. I look forward to seeing more fact that support that news flash soon! Rob

Thanks for talking me down, I just wanted people to understand the gravity of the situation. I didn't want to launch another controversy.

Just out of curiousity, did you happen to do the questioning in a raise-your-hand environment or was it more of a pen and paper questionaire where the responses are less likely to be influenced by their neighboring friends and family? (Not a criticism...just a question.) Anyway, I think its neat that you proposed a bit of research and came back with some results to share. Among other things... You have planted a seed in the mind of fifty people who may walk away with a more comfortable definition of geocaching which may come in handy as the terminology is passed in public and people discuss the newspaper articles and broadcast stories to come. When the people who have experieinced your polling are confronted with the topic in the future, they may have something positive and beneficial to provide to those who are not as familiar with it. Even a passing familiarity in a positive light is better than no reference to a topic at all. Part of the problem with this rapidly growing sport (South Carolina being a prime example) is the lack of knowledge people have of the sport. More questionaires of this type done across the globe and across the board (not just particular races or groups) may not only help with marketing research for GC but also help promote and advocate the sport as a whole. It helps us learn to guage the perception of geocachers by the society at large: Information that will be very useful in the growing effort to keep GC safe, legal and "un-regulated" by those who would have geocaching go the way of the gravity boot. "What's a gravity boot?" you ask. Hmmm. Good Question.

Actually it wouldn't have to be that heavy (approx. 1/6 gravity, you know....). Actually, wouldn't it have to be 6 times as massive in order to be the same weight on the moon? Got to think about that one... BUT at least you could ignore WIND loadings on the pole. Amongst other factors. Scrabblers: It depends on what satellites and for what purpose. GPS (Earth system) would not be good at all. They broadcast towards Earth surface and are so distant that the signals would all come from the same place if they could be received at all. A Moon based MPS nav system would be OK. Doug 7rxc

Actually it wouldn't have to be that heavy (approx. 1/6 gravity, you know....). Actually, wouldn't it have to be 6 times as massive in order to be the same weight on the moon?

Actually it wouldn't have to be that heavy (approx. 1/6 gravity, you know....). Of course, having a cache on the moon would have its advantages....you could use anything at all for a cache container as water intrusion would not be a concern...no more damp logs!

Two logs that made my day. The first isn't even my cache, but it is so cool that I feel compelled to repeat it here. "FTF!! But, OH what a day it was. Started the drive in on Telegraph Canyon Rd, Then on to Ajax Mine Rd. The driving was fairly easy going in my Tacoma. Got to the Orphan Boy Mine Rd turn off to head South, and my concience told me to stop there and hike the rest of the way. I've never been one to may much attention to that little voice in my head. so I drove in a ways. Not too bad. Found a spot to park, and walked the last 1/4 mile or so to the cache. Found the cache easily enough and signed the log. Took a few pictures, then headed back to the truck. This is where the day starts getting interesting. On the way out towards Ajax Mine Rd., I got the left front tire caught in a runoff wash out an the side of the road, as I was just getting the tire clear of that, I felt the left rear go over the edge. After that, it was gravity that took over, and I could'nt do anything about it. As the tires caught during the siways slide, over she went, finally landing on the roof in the creek bed. After kicking out some of the already broken glass, and getting out of the truck, I checked my phone, and I had NO cell signal, and an almost dead battery. So I fished my pack out, and a few other belongings, marked a waypoint for the truck, and headed up the road to a high spot, about 1 1/2 mi, to try and get signal. Called 911, gave them my coords, and waited. After about an hour and a half, and no sign of help, I called 911 back, and stayed on the line with them. About 15-20 min later, I spotted the DPS helicopter. After they finally found a spot to land, they loaded me up and flew me into Superior, to be met by an ambulance. I did not realise how banged up or injured I was, or could have been, because of the adrenilan rush I was on. Once in superior, it was decided that it would be best if I was flown to a neurological trauma center. So, I got a second helicopter ride to Scottsdale. Fortunatly, nothing was broken. Just beat up a bunch. And the let me go home after a few hours. Now we just need to figure out how to get my truck out of that canyon. 2008 Toyota Pickup Truck (Totaled) - Close to $30,000 Medical bills/LifeFlight Fees - close to $30,000 Vehicle Extraction/ Towing Fees - $4,800 Getting the FTF and a Smiley - Priceless Took - nothing, Left - nothing(except my truck, in the canyon) and signed the log. Dipping my personal TB for the mileage and the adventure. This will most probably be my MOST MEMORABLE cache ever. Thanks *Update - June 1, 09* The truck has been recovered. It took the towing company 10 hours, 3 guys, and 3 trucks. They could not get the 24' flatbed in anywhere near, and had to upright it, and drag it out with thier huge 4wd truck." The second is on one of my caches. YOu have to feel good about one like this. "Well my hat is off to you. I can officially crown you owner of the most and best views from caches in Payson!!! I left at four this afternoon and came off the hill in the dark. The hides were absolutely brilliant. Great first container! The last hide is wonderful. I am glad you and I think alike. I walked right to the only large cedar I could find on the east side of the ridge, climbed around sat down and said " hmm- iwould hide a cache right here." Amazingly that is right where it was. The rock placement for camoflage was absolutely incredible. I placed them all back with exquisite care because I can appreciate the effort it takes to find and arrange those rocks just so. Found a rattlesnake in the dark on the way out from the final cache, luckily he sang REALLY loud so he saved us both from a miserable afternoon. Moved the TB from stage three to stage five. I must have missed the other TB. Don't know how, but did not see it. I was in a real hurry a stage four, so I might not have seen it. Can't say enough about what an amazing series this is. Lots of work and scouting. I always love the ones on top of hills and mountains and this does not disappoint. The sunset was beautiful and the bulls were bugling like crazy as I went after stage 5. What a great day caching. Thanks so much for this multistage- Probably the best Payson has to offer! T: Coin out of Stage 5 L: TB from stage 3 to stage 5. Thanks again!"

Bicknell, Testing at the most basic of levels is something where you define a criteria for observing something such as some specific property a certain way on a certain thing and then you observe it the same way many times to gather the desired information. One way the data could be looked at is how the observations compare over time. The old CGS Gravity Station is actually a triangulated station with values for what ever order horizontal survey it had, and additionally it was chosen as a place where gravimeter observations would be made and tracked. So we have triangulated the where of the testing, meaning this is a location where we want to make repeated observations and then we measure the gravity here at whatever the prescribed frequency of testing is prescribed. There is no way to collect meaningful data if a stringent practice is not followed. The procedure has a standard and methodology that has to be followed so the results remain consistent. If we come across this sort of station in the field we will immediately know that it holds additional importance and data that other stations may not have, just from seeing the additional information on the disc. There are also Magnetic stations for monitoring geomagnetism as well. Rob

The US Department of Defense (and other similar organizations worlwide), as well as NASA, have spent many millions of dollars mapping the gravity variations worldwide. It is necessary to know this information for accurate orbital calculations. In fact, even the GPS constellation of satellites needs it! GPS would be useless if the control system didn't know the exact gravity data worldwide, since it effects the orbits. NGS data was fed to NASA, DOD and others. May still be, but it's not something that doesn't change much, as I understand it, barring major rapid earth movements (i.e. earthquakes). All part of mapping, just a different part.

The Colorado uses SD not microSD memory. You must push the SD in a little to click and release. The SD will not simply fall out just by gravity. Your SD slot is defective if it will drop out on its own.

Not anti-inertia either. To be honest, this book was published in 1928 and so well before the stuff it attempts to describe were understood. The mechanism for transmitting the power is very loosely described. Some of that description borders on gravity, but it's more than just gravitational attraction. That said, I'm after just the source of power rather than the mechanism by which that power moves stuff. To make this fair on those who're not familiar with E.E. Smith, I'll mention that getting the answer by reading the book is not cheating, and that some of the Skylark series are available as free eBooks. They can be downloaded in a variety of formats from http://manybooks.net/authors/smithee.html (among others). BTW, I loved the Lensman series when I read them decades ago, but I haven't been able to find more than Triplanetary as an eBook and so I might be a while before I get around to re-reading them!

Not anti-gravity, so anti-inertia? I've only read the Lensman series by EE., not the Skylark books.

I've started using GS's geo app since c:geo stopped working as it used to. I thought it was the bee's knees to start with but i've since found a few foibles with it, but it does the job almost as good as c:geo used to do it. At least now it's a purchased app there is some gravity gained regarding requesting updates etc. at least i hope!...

Doc, I am in understanding with what you say, in fact you have said many things I have said here many times but not in complete agreement. We see the world a little differently but mostly the same, I take no offense at all. NAD 83 compensates for a lot of Tectonic plate movement we see here out west, and is specialized as a Datum for the North American Continent and so it is much more accurate than WGS 84 in this country. I am aware we tossed NGVD 29 out in 1991 and now go with NAVD 88. Not just the former reference of 26 tidal stations as opposed to a single one in Quebec, but they were right to confirm that mean sea level as a stable actuality does not exist. It was basically the Surveyors Loch Nest Monster, an elusive creature. Since we have an unstable apple and an unstable orange, yet they need to be compared by virtue of both being fruit that grew on trees as a commonality, what can you do? This is what Vertcon tries to attempt. I mean if an orthometric height comparison is needed between datum you are bringing Geoid height and ellipsoidal height to the table, Orthometric height differences can then be obtained from ellipsoid height differences by subtracting the geoid height differences. As an orthometric height is a derivative of a geoid height, (which model?) and an ellipsoidal height, (again Which model?)(NAVD 88) We have to define our terms and remember that Clarke 1866 was not used Vertically,(NGVD 29) and sea level is ah.... Tidally dependent on 26 averages that were ahhh not then known to be geoidally (gravitationally) dependant.(NGVD 29) When even differential leveling is path dependent, taken as a whole, it is a tough apple and orange to compare, yet all considered orthometric heights all the same. I am also aware that when NAD 83 was adjusted from NAD 27 all stations were not changed with a Nadcon or Vertcon adjustment. You are correct in stating 67% confidence but the ballpark is taken as .15 meter in the continental US and that is 6 inches roughly. With it we should be able to use the NADCON program to Find the survey marker and that is good. If we are a Surveyor, we then know what we need to do. If we actually have to use NADCON or VERTCON, then the survey is considered low accuracy, the onus is on us to state this and the buyer is beware the accuracy. Accuracy is plainly stated by NGS. I am not saying I don't find errors either because I do. But it is not with A, B. and first order work as much as with third order. There was a least squares adjustment based on new leveling and triangulation of the networks during the 80's. I take the NGS term ADJUSTED to mean a least squares adjustment rounded to the fifth decimal. Not bad really, and close enough for most infrastructure. Yes there are inaccuracies, but I am glad I am not doing this with a Wild T-3 and paper with pencil, aren't you? Besides, the entire NGS database is not the NSRS. I have found GPS comparisons to be very good with the NSRS data, and Optically triangulated third order stuff is not taken as NSRS quality. I don't take the Geoid in either 99 or 03 to be a static force so I realize despite the spheroid models being used, the earth constantly moves, the atmosphere and it's distortions never end, the constellation of satellites is up and down, on and off and there is no less than several government agencies in control of each little part of the puzzle. Either way, when you get to the highest accuracy, there still is no one sure place. If you could attain it you would never arrive at the same number twice. Either way, that one sure place is a difference of approximately 1 meter due to the datum shift between NAD 83 and WGS 84. Besides, It is all in constant motion. This big earthquake a week ago has not done us any favors when it comes to trusting numbers. I would say that many bets are off on Geoid 03 now. It seems hard to trust a Gravity Model after a 98 foot tectonic shift. Beyond that, Both NGA and NGS have done so much accurizing of both their Datum as it is that they really only continue to call them by those names as a political courtesy. Neither one of these are close to the datum they were when so named. We are aware that political needs come before the scientific needs. Always has. Prepare for another update soon. As for HARN problems from State to State, and the fit problems, well I see that as a bit of a political situation as well. I have heard that not all states are playing the HARN game the same way and until they do, I don't see how we can really ever prove a thing. Again a Political problem is likely the culprit more so than the science. More so, no one will ever officially comment as such and we both know that. If it is the science, we would have to see after we cure the political problem. Science has been found to not best describe reality before so I would not be surprised. In these parts we still have counties that insist all vertical control be done to NGVD 29 Datum. But cross a city limits the vertical control becomes NAVD 88 Have that County road hit a State Highway and you immediately have a Datum Shift. Yup, It's a pain. All Political. You can take my old datum if you can pry my cold dead fingers from it. Imagine the fun I have laying out a gravity pipe job complete with datum shifts. Bleh. Each municipality will extract it's due. Most interestingly this horror tale often comes true brought by a inspector who has never heard the word Geodesy. The Hellbentness that you say about NGS is true in the respect that they are finding better ways to accurize their Datum as the science and technology becomes available, besides, I am not sure we know all there is to know about geodesy yet. From what I read, there is a lot still being revealed. Don't get me wrong, I am not trying to big deal it but look how far we have come in the last 40 years, 20 years, and 10 years. Maybe the 6000 became 600 but much of the heavy lifting that once was necessary is done, and done by old ways. We have easier ways now. I was a member on a crew of 3-4 back in the Day and most of the time I am now a force of one. I think NGS probably let go of 2000 of the bunch of 6000 when computers took over the calculus. That was a lot of pencil and paper... Since WGS 84 is used worldwide by other countries and governments, those countries (Europe, Asia) who use it become a local accurizer of that datum, and are equally hell bent, So much so that they are developing their own GPS systems and Datum, so you see it really isn't different, other that the truth of the political matter. WGS 84 is really about DOD and that means Bombs and missiles, and here in this country there is not a lot on the ground to accurize it. NAD 83 is about the north american continent. When it comes to what is going on in the dirt on this continent, I feel the NAD 83 is far more accurate. Either way, I have to tie in to the right numbers. The difference truly is that Plate movement is different in North America, and WGS 84 was not developed to account for it. The question of accuracy is highly unanswerable the closer we get to it. It is like the last mile of a fiber optic network or absolute zero. You are right, It is nothing which can be seen in the hand held unit of consumer grade accuracy, but it is not correct to have people think that WGS 84 is substitutable for NAD 83 as that is not correct and wrong minded. There is no point in developing bad habits or wrong thinking at any level. It doesn't serve anyone well. And no, I don't use Nadcon or Vertcon for hard survey numbers. Those have to come from field observations as you know. But they have their uses. In the end, I am not trying to argue the Math with you Doc, nor am I really trying to contradict you, as all your points are good in many ways, but this is the system we have and despite flaws distortions or Fubars, it is what we have and we should use it. It came from marginal instruments and mathematics which had barely been developed to what we have today. We did give up Clarke 1866 for GRS 80 and we may yet give up GRS 80. I know it is a pain and a work in progress, but still I'd like to think of things becoming more correct, not less. We may be able to measure to the gnat someday, if we can find the gnat and get it to hold still. Rob

I think Edward is spot-on here. The popularity of location-based utilities (like the geocaching website) and mobile apps (tablets and smart phones) is really, really bad news for us all. A few years ago you could run a free tile server and maybe get a few hundred, or a few thousand hits per hour. Now you have millions of people using androids and iPhones as their car GPS... Lay users just don't understand the gravity of the problem. Not even google can afford to provide the scale required for millions of tile server hits per second for free. The CPU and bandwidth costs to serve up tiles at this volume are simply staggering. One by one, every free map service has been utterly crushed into non-existence by user demand. Our appetite far outstrips our ability, or willingness to pay... The free tile server model started to crumble about two years ago, when a few regional/niche tile servers had to send out cease-and-desist letters to mapping software authors like mobac and Locus. Since then the closures of free services has come like an exponential tidal wave. More and more previously free map services have had to go to an API Key model to stem the tide. Once one goes away, then all those thousands, or millions, of users simply migrate to the next free tile server they can find, until we crush that one, which then has to stop providing free tiles too. The tidal wave has become so large that not even google can take it any more. Map tiles have become the crack cocaine of a mobile society. As for performance, this is another place where the free model is breaking down... Tile server operators do not want you to cache (temporarily store) tiles locally, and their ToS will usually prohibit this. I think that is the problem we are having, and will continue to have with the aerial images on the geocaching website. Caching of just-viewed tiles is probably prohibited and thus, every time you zoom in and out, or pan your map, you are reloading a fresh set of tiles even if you just had that tile loaded seconds ago. Again, this is the way of the future, no free tile server can afford to allow local caching of tiles any more. Again, I don't think we really understand the size of the problem. It isn't JUST geocachers, it's millions of us worldwide, roving from free server to free server like a band of marauders. The "everything free all the time" model is not sustainable. It never was.

Or ... how about if we just stop complaining, period? We know there will always be people who don't expend the time, effort or expense to fill caches with "nice" stuff. It's a fact of life. Complaining about it is sort of like complaining about gravity. I get so p***ed off when gravity holds me to the earth and I can't slam dunk a basket ball.

Unless you happen to be next to a black hole, I'm pretty sure gravity doesn't play that much a part in accuracy. Large rock masses may cause multipath or block line of sight to a satellite, and power lines may cause electromagnetic interference. Point? Gravitational sources does not affect accuracy in any perceptible way.

Unless you happen to be next to a black hole, I'm pretty sure gravity doesn't play that much a part in accuracy. Large rock masses may cause multipath or block line of sight to a satellite, and power lines may cause electromagnetic interference. Point?

Unless you happen to be next to a black hole, I'm pretty sure gravity doesn't play that much a part in accuracy. Large rock masses may cause multipath or block line of sight to a satellite, and power lines may cause electromagnetic interference.

That could be it. The version I am posting screenshots from is DSWorld 2.10.19 I do recall using an older version of DSWorld that didn't let me select multiple photos. This is probably the version you have. Here is Malcolm's list of changes just from version 2.10 to 2.10 + What's New Version 2.10+ Stations>All NGS IDB>By PIDs selection added. FTP tool added. File output directory change added. Get>List of Photos by PIDs added. Calibration baseline (CBL) data viewer added. Ability to send multiple photos added. Additional photo name checking added. HH position submittal form changed. A new photo problem reporting procedure has been added. Photo editing and submitting procedures modified to allow 1024 x 768 photos. The ability to view NAVD88 vertical control was added to the control type selection menu. The projects menu item was moved under Stations. CORS plotting options added Observed gravity information link restored New photo editing tools added. Disk type editing added to photo edit tool. Disk logo editing added to photo edit tool. New data transmission logging added. Disk stamping editing added to photo edit tool. View datasheets by PIDs menu item added. One can now change the registry timeout setting. I am also going to add this part, in case anyone may be having problems getting a timeout error. 12/17/11 - Timeout problem Microsoft's internet explorer (which DSWorld's WinInet.dll uses) has a timeout setting of 30 seconds by default and was overriding DSWorld's timeout setting. The 'Stations by project ID' retrieval and other processes can take up to a minute or more. To fix: 1) Start DSWorld. 2) Click 'Tools>Options>Change Timeout Time' from the main menu. You will be prompted to change the registry entry for the timeout. Select a time in seconds up to 120 seconds. Note: This setting becomes the new global timeout which applies to both Internet Explorer and any WinINet application. The setting only applies to the current user. Other users on the same computer will have to changethe setting for them. 3) Re-start the computer for the new setting to take effect.

Wow! Stu and Sandy aren't afraid to jetski even in the most dead defying places!