LSUFan

Artman, you are correct. The number and position of the satellites (the "constellation") make a big difference in the signal. Has anyone ever noticed that at times you get great accuracy and other times, even though you are "outstanding in your field" so to speak, you can't seem to get a good signal. Well it all has to do with the constellation--what satellites are visible and high in the sky. GPSWorld discussed this in 2009 There are calculators for determining the best times to get GPS readings. Trimble has a downloadable one.Navcom has an online one. I am sure there are others out there. Edit: found an even cooler one (through a link on the John Deere site). http://navcomtech.com/Support/Tools/satellitepredictor/main.cfm Thanks for that link, mloser. I just bookmarked it. Not trying to get off topic too much, has anyone here had much experience with the Russian GPS system (GLONASS)? I've been reading where a lot of the smartphones can use our and their systems......as well as some units able to read both at the same time. I was just wondering how accurate of a reading you could get utilizing both systems at the same time.

Thanks for finding out where Garner is. It's a good ways from Louisiana. I am just guessing, that it is some kind of data entry error, for the reason those two disks are showing up in the photos for Louisiana's COP.

If the mark is not in the NGS database (which is what gc.com has on their website, or actually a copy of from around the year 2000)......then you can log it in the benchmarking category of Waymarking. http://www.Waymarking.com/cat/details.aspx?f=1&guid=424f2581-a02d-4914-9bc8-8f4cafe02680

The first thing you need to understand about benchmarks is if the coordinates listed on the datasheets are "adjusted" or "scaled". Adjusted coordinates will be precise, even more so than your handheld gps unit. Scaled coordinates can be off as much as 600+ feet. Here is some reading on that subject. http://www.geocaching.com/mark/default.aspx#adjscl http://www.nelageo.net/index.php/forum/13-benchmarking-and-related-topics/10956-understanding-a-ngs-datasheet-scaled-vs-adjusted-coordinates

Patty, if you are a GSAK user, then it is easy to do after a little initial preparation and learning curve. Garmin has it's own piece of software called POI Loader for placing poi's on its units. However, you first must take the datasheets, and get them sorted to your liking....which is what GSAK can do. This forum below is about placing benchmark POI's on the Garmin Nuvi......but CallowayMT also placed them on his Garmin 62, and he might can answer your questions concerning a Garmin handheld instead of the Nuvi. And yes, these benchmark poi files store the entire datasheet (at least on the Nuvi). http://forums.Groundspeak.com/GC/index.php?showtopic=267951 From what I have read on the Garmin site, I believe you can load just a direct gpx file into the POI loader software and make your own. You might can bypass GSAK all the way.I bought my son a Garmin Dakota a few months ago. I will play with it some this weekend and see what it takes to put the datasheet poi's on it......and if I can do it without GSAK in keeping all the datasheet information intact.

Was that disk set in 1961, or am I reading it upside down? Jim, you dog. I caught myself turning my head to see the if the numbers were upsid..............then just started laughing. My mind is working real slow this Friday afternoon.

Ok, I am firmly placing the blame for my obsession for finding one of these on you now, frex3wv. When I look at CQ3244 on google maps, I can see a four-legged tower, and it looks real similar to the ones in the history links provided. However, there also seems to be more mast above the platform, which I guess could have been added later. I will be over that way in a few days and take a looksee. It is all fenced in, so I won't be able to get but so close.

OK, all this talk about old airway beacons got me curious as I have seen some datasheets for them before in my local area. Normally I don't do many intersection stations, but the history of these was too tempting. I used GSAK to filter them out and it appears there are about 5 of these old airmail route ones still listed in the NGS database for LA, and they are all on the Ft.Worth to Atlanta route, which passes right over me. I used google earth/maps to see if I could see any structures but couldn't decide on what I was viewing on a few of them. I happened to be near three of them today........and you just know I had to take a personal gander (wouldn't you?). None of the three were there (and I didn't really expect them to be). There is one that maybe is there. It is further west, but I will be that way later this week to check, and the power squadron submitted a found recovery report on it in 2003. The satellite view and street view show a three-legged tower, so this may not be a true one. I now need to say it's all frex3wv's and EdrickV's fault.

Maybe, they're off doing ninja training.

Thanks southpawaz. I am 99.9% percent sure this LOT is not there anymore. It is almost across the road from where you park to access the trail to Mount Driskill (the highest point in LA). As many times as I have went up Driskill with geocaching friends, I believe I would have noticed a fire tower nearby. I think there are just cell phone towers there now, but will definitely make sure the next go around. I think I looked one time, but may be confusing this with another one. I might be able to search for the Gentry triangulation station though, depending on if there is access. It's probably fenced off.

Is it safe to assume they took the elevation of the base of the LOT on the topo map, and didn't add the 80 foot to it......and/or does the term orthometric tie it to the surface of the earth? Thanks

As usual, when Jim/Holograph posts his monthly statistics, after I look at the maps, I seem to always end up looking at the extreme stations while on his site. I keep looking at the highest elevation benchmarks for Louisiana, and noticed something today that I haven't really studied........so I brought my questions to the experts here. The highest benchmark in LA is the Gentry LookoutTower CQ2886 and the point intersected is the TOP CENTER OF A 6-FOOT SQUARE CABIN SUPPORTED BY A 4-LEGGED STEEL STRUCTURE WITH AN OVERALL HEIGHT OF 80 FEET. It's scaled height is 512 feet. It has adjusted horizontal coordinates. Now the second highest point is Gentry triangulation station CQ2887 This station is down on the ground near the Gentry LOT. However it's elevation (vertcon)is 511 feet....or one foot less than the 80 foot high Gentry LOT In obtaining the elevation for the Gentry LOT, would they have just measured the ground level that the LOT sits on? I don't guess I have enough experience with intersection stations to have ever really looked at how the elevation information is derived for them. I just thought it was real curious the there was only 1 foot difference between the two........even though one of the points is 80+ feet above the other. I'm just guessing that difference is because the LOT has scaled elevation numbers (which just coincidentally put it within a foot heighth of the other), but would welcome any guru knowledge about this. Thanks

John, using DSWorld...... clicking "Stations", then Published, By State & County (Beaver County, UT)....I see what you are talking about. Those two lines run way down into Iron County.

John, do you use the current version of DSWorld? It has a way to submit correct state/county listings to the NGS You can also use DSWorld to see the counties on Google Earth, and get lists of all the NGS marks listed for each county....to check and see if they are correct.

A local store that sells surveyor supplies/equipment may also have the 7.5 minute topo quad maps for purchase. I think they are 22" X 27" and 1/24000 scale. We have a supply store like that here in Monroe, LA that sells each quad for the entire state of Louisiana. They're all in drawers (like a tool chest), that you pull out the drawer and get the map. You might can look in the phone book under "surveying" to see if there is a store that sells supplies nearby and give them a call.

Thanks everyone, for the responses.

On GC.Com logs, I think it is OK to say whatever you want. If you have an experience that deserves telling, I tend to believe that all of your fellow benchmarkers would like to read it. Ex: "and the smell was so bad that it would have made a skunk commit suicide" Now if you log with the NGS, just factual.........and in the same terminology as you read on the actual datasheets.

I'm heading out of town this evening for a football game, and plan to check on one tomorrow that I hope the Power Squadron couldn't find (2 different times). I think I may be seeing the actual benchmark from 1919 on the side of a building using Google Maps/streetview ....but can't tell for sure. I will know tomorrow if I can correct (or agree with) their assessment.

There used to be a pdf benchmarking explanation sheet (similar to Geocaching University) that kinda explained what you were doing to landowners. I downloaded this and had many copies printed out.....but can't for the life of me remember where I got it. Maybe others here can point it out, and you could add it to your presentation.

I know all the government agency acronyms can get confusing too. The USGS (United States Geological Survey) and the USC&GS (United States Coast & Geodetic Survey)are two different agencies.....but almost have the same letters so you have to be mindful of them. The USC&GS is what is now the NGS (National Geodetic Survey) and is the database we use on geocaching.com. Here are some links to both of them, and helps explain their different functions and purposes. These links are great reading (when you have time)......explaining the NSRS (more acronyms) and the history of the USGS (many pages) http://www.ngs.noaa.gov/web/about_ngs/history/ http://celebrating200years.noaa.gov/foundations/spatial/welcome.html http://pubs.usgs.gov/circ/c1050/intro.htm

BlueMoth, welcome to the world of benchmarking, and congratulations on wanting to get it all correct. There is a little learning curve, but you will get it. Your question is probably the most common one in these forums (I asked it myself). Hopefully, the following which is copied from the benchmarking FAQ's will help....including on what to do with USGS disks not listed in the NGS database: http://www.geocaching.com/mark/ Benchmarks Not in the Database I found a benchmark, but it isn't in the database. Why? To answer this question, you need to understand a bit about what "the database" is. The database used by Geocaching.com is a copy (from around 2000) of the database that NGS maintains. Although the NGS database has lots of marks in it, it does not have them all. In order for a mark to get into NGS's database, it has to go through a process known as "bluebooking" which ensures the disk meets the minimum requirements to be of geodetic quality (aka the highest quality possible). The NGS is not the only organization that creates and uses benchmarks and other types of control markers. In order for any mark to get "in the database" they must be "bluebooked", which can take a lot of time and effort and is often not done to save money. Remember, even though some marks might not be in the database, they are still highly important, both to businesses and to individual citizens such as your neighbors, so please treat them with respect, while enjoying the thrill of the hunt. We'll try to find other databases and add them to the site as well. If you have access to one of these databases and would like to submit it to Groundspeak, contact us. Since the Groundspeak benchmark database was obtained from the NGS in the year 2000, newer benchmarks and recent reports on older marks will not be visible here in Groundspeak's copy. Besides new disks, there are many cases of benchmarks monumented significantly before 2000 but entered the NGS database only after the year 2000. The benchmark I found is not in the database, how can I log it? If the benchmark is a disk-type marker or is referenced in an online database, you can log your find in the US Benchmarks category in Groundspeak's Waymarking site. If the benchmark is in Canada, you can log it in the Canadian Benchmarks category in Waymarking. I found a U.S. Geological Survey bench mark where there is a "BM" mark on a topographic map, but it isn't in the database. Where can I find more information about this kind of mark and how can I log them? The U.S. Geological survey (USGS) established thousands of benchmarks to help them make their topographic maps. The number next to the "BM" is the originally measured elevation of the disk. A large number of these USGS marks are not in the NGS database be cause they were never "bluebooked" as explained in the section above. The NGS and the USGS are separate government agencies so the inclusion of USGS marks in the NGS database is not automatic. Unfortunately the USGS did not get their paper records of benchmark location notes onto computer files. This makes those USGS marks that are not in the NGS database quite a challenge to find! You can log USGS disks you find that are not in the database in the US Benchmarks category in Groundspeak's Waymarking site.

Hey Everyone. I got to find one benchmark while on vacation this weekend and it looks like it may have been reset by a crew who put in a handicap ramp in place of steps. Would you mind looking at the pics and reading the datasheet......then giving your opinion? The datasheet says it should be in a step, but it is now in a handicap ramp, and is angled where it would have been placed in the ramp when it was made. I made an initial log on gc.com, basically as a way to place the pics for everyone to see....and will edit it accordingly. Thanks Bobby http://www.geocaching.com/mark/details.aspx?PID=EJ1548

As Wister6813 pointed out above, if the RM or AZ mark doesn't have it's own PID, then you just leave that part off of the beginning and start with the name (then everything else is the same)..... and would include the pics in with the triangulation station mark recovery. I have submitted some like this, but actually used the PID of the triangulation station, then the name/number of the reference/az mark secondly. Apparently, I wasn't supposed to do it like that........but without a PID, it would be hard to look at later and know which station the reference/az mark went with....just from the name itself, especially if the station is a common name. I guess the NGS isn't going to give me that raise I asked for. LOL

Mike, a little more clarification on the naming schemes The photo numbers of 1,2,3 (or more with earlier releases of DSWorld) that come after the marks name, are specific to the view you are capturing. You will use the number 1 when it's a closeup pic of the mark You will use the number 2 when it's a tripod height/eye level pic of the mark You will use the number 3, then add the compass direction initials you are facing, when it's a horizontal/scale pic of the mark. With earlier releases of DSWorld, you could just keep using higher numbers of 4+ for each scale pic you submitted. However, it seems with the latest release that every scale pic is going to have only the number 3 and compass direction with it.....even if you took 5 scale pics, they all will have the number 3 in the name. I also talked to Malcolm about why DSWorld will actually name the pics one way, but change the order of the PID/Name on the pic when you use the software to put a stamp on the pic itself. He said that was the way NGS wanted it. So, to make it simple for naming the actual jpeg photo. It needs to be the 1.PID# (then a dash -) 2.mark name (use underscores_ for spaces in the name)(another dash -) 3.number of photo (1 for closeup, 2 for eye level, or 3 for scale/horizontal...if it's a 3, then you also need the compass direction following (N,S,E,W,NE,NNE, etc) then (another dash -) 4.Date photo taken (YearMonthDay all together, no spaces) Here are some examples: I use DSWorld to name the pics for me as well as stamp them for me......and use the same named photos for geocaching and NGS recoveries now. You can see the name of the pics and when you click on them, you can see how the stamp has the PID/Name order reversed.....but that's what DSWorld does. Also, I didn't take a tripod/eye level pic of the mark, so there is no # 2 pic http://www.geocaching.com/mark/details.aspx?PID=BW1569 http://www.geocaching.com/mark/details.aspx?PID=DK0988 Using DSWorld (or manually doing them in the NGS format) to name the photos does make it a lot easier to go back and look them up again on your computer. You can instantaneously look at the name and know what it is.

Thanks. I saw a bunch on the Capitol, but just a few close to the White House, using Scaredycats viewer. I figured that they must be marks not necessarily listed in the NGS database.