Benchmarks (those established by the National Geodetic Survey) are reported in Geocaching.com, but do not count as "cache finds" - they're listed separately.Originally Posted by becket
I have always been amazed how accurate benchmarks are considering the limitations of how they were placed. Imagine setting a benchmark on some remote Maine mountain top 80 years ago.
One of the benchmarks is the compas flower used to calibrate aircraft on BNAS's runway. I am sure that there are more of them at other airports but that is just the one I know of.Originally Posted by WhereRWe?
If you want to 'compare' the coord's you get with your GPSr all you have to do is look for horizontal control points from the NGS web site and then stand over one. As far as the precision with with the 'benchmarks' are located...I was a geodetic surveyer for the US Army (1981-1985) and, although dependent upon the order of precision required, we routinely set new control stations (horiz) to within a few centimeters. Even back a couple hundred years surveyors were setting monuments that were located more precisely on the face of the earth than rec GPSr's can locate today! George Washington, Thomas Jefferson, Lewis & Clark, etc. The list goes on and on. For a fact, though, I'd much rather be surveying today with modern instruments and GPS. I digress....
As far as comparing to "known points" I'm not sure what good it will do because recreational grade GPSr are only going to give you a best case position within a few meters. You may get the same coordinates multiple times as WhereAreWe? said (that's "accuracy" of the GPSr) but that doesn't mean the coordinates are "correct" (precision). Comparison to a known point will give you an answer if you think there's something wrong with your GPSr though. I'm sure everyone has stood in one place and watched the relative accuracy read-out on the GPSr go from 20' to 12' to 40', etc. The position is a function of satellite geometry and satellite health at different times during the day. When I go out to do a GPS project I'll use mission planning software that will let me see the best times during the day to perform observations based on location, obstructions, etc.
The best solution is for most people is occupation times. Make sure you are receiving the WAAS satellite for a differential correction and just wait a few minutes for an averaged position. My etrex doesn't actually tell me it's averaging but the Magellans I've seen tell you it's 'averaging'.
What do the new Garmins read-out (60 & 76 series) when you're "averaging"?
Last edited by mainesurveyor; 02-25-2006 at 03:41 PM.
Well, I'm often wrong when I open my big mouth, but don't we have some spirited discussions? LOL!
I still want one of the "more accurate" X-series Garmins.
I love the discussions...I know y'all don't know me very well but I have a tough hide. I'm not taking anything said personally...unless I get compliments, of course. I just like to add some detailed input to a discussion. Sorry if it gets a little in-depth sometimes.
This is a great board and a great pasttime. I hope to get out a lot more this year.
Feel free to move this portion of the post to a new thread but I've hesitated to do caching this winter because I was concerned about the snow (not that we've had much this winter). What are cacher's thoughts about trails in the snow to the caches and the no longer snow covered 'pile of sticks'?
This is the perfect winter to cache! We've had so little snow that most caches are easy to spot.
By the way, I almost emailed you regarding this post because I was sure you would know exactly how benchmarks worked.
Originally Posted by mainesurveyor
I think the lack of snow this winter has really been a non-issue but even when we have more snow, the winter time is one of the best times in my opinion to go caching. No bugs for one thing,lack of muggles most of the time,even with tracking foot prints through the snow unless you are the FTF most cachers that I know of will create false foot prints all over the place to confuse the next cachers hunting for it... I also usually bring a pokey stick to poke around under those telltale pile of snow laden humps . That familiar thud or clink will tell you if the cache is there. To me walking down a beautiful snow laden trail with boughs hung with that fresh white stuff,what can be better or more beautiful. JMO Any others?
Just smile it won't crack your face
The statistics on sanity are that one out of every four persons is
suffering from some sort of mental illness. Think of your three best
friends -- if they're okay, then it's you.
Just having come back from a "real winter" place, Quebec. It was beautiful with 3 feet of snow on the ground. We even found a reg cache that we had to snowshoe to. Like Haffy being out in the winter is a wonderful almost magical time. All quiet and clean and crisp. Oh by the way. Crisp in french is.....darn near impossible bone chilling cold with a wind whippin off the St.Lawrence Seaway at 20 degrees below zero, COLD. It's tough to enjoy the cache when your freezin your.....fingers off. Glad that we were back in Maine, we did Goodwill-Hinckley in 30 degree weather. And enjoyed the walk in the woods. Ahhhh.. a Maine winter.
Why not live life like it is your last day....instead of pretending to be a member of the Peter Pan Club and believing you will be around forever.
The only problem I've run into caching this winter is with caches frozen in. With all the rain and then cold following they seem to get adhered to the ground a lot of the time. We went caching a few weeks ago in the snow at 14 degrees and it was great. Dress for it and all is good.
Yeah it's a Jeep thing!