Search the Community

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

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!

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?

About to go look for a couple benchmarks in Riverside CA area, and I noticed they are both listed as a "Gravity Station Disk". Anyone have any idea what that is, how it is used? Here they are: http://www.geocaching.com/mark/details.asp?PID=DX3592 http://www.geocaching.com/mark/details.asp?PID=DX3593