I!
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Posts posted by I!
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Hoosier Ranger, I want your GPSr13.2 feet of accuracy100 averaged locations
11 satellites received
!!!Many thanks for the data. Table updated.
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Here are the scores on the doors so far:
+--------------------------------+ +------------------------------+ GPS receiver reported ... +----------------+ | Google maps location | location | accuracy | contributor | +------------------------------+---------------------+----------+----------------+ | N 29° 43.###' W 095° 46.###' | N +0.001' W +0.000' | 13 feet | Hoosier Ranger | | N 30° 54.###' W 084° 34.###' | (~30 feet North) | ? | GeoBain | | N 37° 01.###' W 088° 41.###' | N -0.001' W +0.000' | 17 feet | trailhound1 | | N 37° 01.###' W 088° 41.###' | N -0.003' W -0.003' | 17 feet | trailhound1 | | N 37° 24.###' W 122° 05.###' | N +0.002' W +0.000' | ? | niraD | | N 41° 38.###' W 088° 14.###' | (5.25 feet away) | ? | Markwell | | N 40° 59.###' W 074° 57.###' | ? | 174 feet | mchaos | | N 41° 01.###' E 028° 57.###' | N +0.015' E +0.011' | 20 feet | ustune | | N 41° 49.###' W 103° 47.###' | variable (way off) | ? | StarBrand | | N 43° ##.###' W 080° ##.###' | N ±0.002' W ±0.001' | ? | dfx | | N 51° 51.###' W 002° 04.###' | N -0.004' W -0.002' | 131 feet | I! | | N 51° 51.###' W 002° 04.###' | N +0.001' W +0.002' | 24 feet | I! | +------------------------------+---------------------+----------+----------------+
To clarify: in this table, "GPS receiver location N -0.001' W +0.002'" would mean that the GPSr reported a location 0.001 South and 0.002 West of that claimed by Google Maps.
So, yep, there are some places where G-maps are pretty well calibrated and others where it's baaad.
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In a nearby town, Google Earth is near spot on in the center of town with features and GPS coordinates and many caches. Just 15 miles East the images are a good 150 feet off as are then given coordinates. Useless for caching. See: http://www.geocaching.com/map/default.aspx...;lng=-103.79042
North of here, about everything is 25 foot off and just another 5 miles away - everything is a good 250 foot off.
This is really interesting. Your map, switched to satellite view, is most illuminating: it shows that the images have been stitched together. I wonder if you notice much variation in Google Maps' accuracy either side of those 'stitches'?
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•Standing at Google Maps point: N ## 01' 01.58" W ### 41' 22.84"
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•Standing at Google Maps point: N ## 01' 03.07" W ### 41' 24.58"
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From these two locations Google Earth and my PN-20 are not very different. Even though I have seen Google Earth not show cache locations accurately before.
Thanks! I'll add these data to a single table later - but no time now as I'm late for work.
(btw, I'll assume these are in the vicinity of N 37° W 088°)
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@dfx - let's stick with satellite view, thus getting round the aerial view problem (which in any case is minor, like GPSr variation, compared to the large-scale calibration errors that I'm asking people to demonstrate).
@ustune - thanks for the data!
@mchaos - how far different were your Google Maps and GPSr coordinates?
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This is a waste of time. Your GPS is not going to give the same reading every time you go back to that spot. (At least, mine doesn't.)
No, GeoGeeBee, it's not a waste of time. If Google Maps calibration is as bad in places as is claimed then it would be instructive to see evidence of that in data of the proposed form. Then, at a glance, we can say that Google Maps is horribly-calibrated in locations X,Y,Z and pretty well calibrated at A,B,C. We might even be able to draw some evidence-based conclusions about accuracy vs. latitude, say. I think that would be interesting; and few-feet natural variation in GPSr readouts would not significantly detract from that.
EDIT: mchaos, thank you, that's what I'm getting at.
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as for my own caches, the only cache where i can even try to use google is my one and only LPC (which is a puzzle cache). the difference is .002 minutes in the latitude and .001 in the longitude
Cool. So that's two data points now:
- Standing at Google Maps point: N 51 51.### W 002 04.###
- GPSr reported location: N 51 51.###-004 W 002 04.###-002
- GPSr reported accuracy: 131 feet
- Standing at Google Maps point: N 43 ##.### W 080 ##.###
- GPSr reported location: N 43 ##.###±002 W 080 ##.###±001
- GPSr reported accuracy: ?
Any more? How about the original poster?
- Standing at Google Maps point: N 51 51.### W 002 04.###
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is there a site or a tool that allows the hider to see property lines? apparently i hid my newest one within the property lines of a government building, it was well outside of the fence, and therefore i figured it was outside the property lines, any help?
It doesn't help you in the U.S. except perhaps to give a glimmer of hope, but here in Blighty there's MAGIC. I understand that geocaching reviewers use it in assessing whether or not a cache may require permission to place, e.g. because it's on land owned by the Woodland Trust, or a Site of Special Scientific Interest, or whatever. Very handy.
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eTrex Legend, 2002 model, since you ask. Next time you upgrade to a new GPSr, feel free to donate the old one
lol? what kinda GPSr is that? iphone?GPSr reported accuracy: 131 feet
Back to the plot ...
Come on, people, let's have some quantitative data, like this:
- Standing at Google Maps point: N 51 51.### W 002 04.###
- GPSr reported location: N 51 51.###-004 W 002 04.###-002
- GPSr reported accuracy: 131 feet
- Standing at Google Maps point: N 51 51.### W 002 04.###
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I'd be interested to see how closely GPSr typically matches Google Maps in various places.
Example, partially censored:
- Standing at Google Maps point: N 51 51.### W 002 04.###
- GPSr reported location: N 51 51.###-004 W 002 04.###-002
- GPSr reported accuracy: 131 feet
Any others want to play?
- Standing at Google Maps point: N 51 51.### W 002 04.###
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Ah yes, fuel. Geocaching creates unnecessary car journeys, poisoning the planet. Discussi did not disagree that spending money in america fuels the american economy
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I had to do some research before I understood this thread (oh, I'm such a forum n00b)
then I found this ... hahahaha!
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Such verbosity. Drop the 'N'.Ni! -
third, as a cache finder, do you avoid multi's since sometimes they can not only be way more difficult to get the smiley, but they may run you all over town looking for the next stage in the cache.
I tend to cut multis short with a bit of internet research, then go straight to the final. I suppose it's like treating a multi as a mystery cache: great fun if you like puzzles, and it works for about half the multis round here.
And, yes, to answer your question, a factor in me doing that is my reluctance to be "run all over town".
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If there's a particular micro-saturated location in which you'd like to place a cache, have you considered putting the cache there anyway (but not -yet- attempting to publish it) then mailing the guy politely to say "I'd really love to activate the ammo can at <coords> but am barred from doing so by the saturation guidelines. Would you consider removing cache GCxxxxx to make space?".
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My preference is neither urban nor forest, but rural. The finds are usually pretty easy, but the walk's lovely.
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Do Groundspeak entertain suggestions for updates to the Guidelines? For example:
Cache SizesThese sizes apply to all caches that have a physical container.
- Micro (35 mm film canister or smaller – less than approximately 3 ounces or .1 L – typically containing only a logbook or a logsheet)
- Small (sandwich-sized plastic container or similar – less than approximately 1 quart or 1 L – holds trade items as well as a logbook)
- Regular (plastic container or ammo can about the size of a shoebox)
- Large (5 gallon/20 L bucket or larger)
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Other (not adequately described by size alone - cache listing may give further information)
There is also a "Not listed" option intended for use when the owner does not wish to reveal the size of the cache.
- Micro (35 mm film canister or smaller – less than approximately 3 ounces or .1 L – typically containing only a logbook or a logsheet)
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I hope GeoBain joins in. Hide to find ratio 58:0 ... er ... what?
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There's no misunderstanding. I choose to disobey the Guidelines' instructions on how to obtain accurate coordinates.What part of the word "must" are you having trouble understanding?Let me say it again (have you taken your blood pressure pills?). I CHOOSE TO DISOBEY. *gasp*
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dfx, Google Maps are evidently well calibrated to the true coordinates where I live, so I'll continue to use them. Sure, g-maps' coordinates may not be accurate everywhere on the planet, but that doesn't warrant a blanket ban as implied by your opening "can't use google maps/earth to place caches". Your later "not supposed to" is much more reasonable.
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@dfx - I should be used to barnacle-like adherence to The Guidelines by now, shouldn't I?
Of course you are referring to:
You as the owner of the cache must visit the site and obtain the coordinates with a GPS. GPS usage is an essential element of geocaching. Therefore, although it is possible to find a cache without a GPS, the option of using accurate GPS coordinates as an integral part of the cache hunt must be demonstrated for all physical cache submissions.I choose to obey this in spirit, not to the letter. The comments I've had on my hides have demonstrated the option of using accurate GPS coordinates as an integral part of the cache hunt. Finders happy, job done.
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of course. you can also bury your caches. or place them on somebody else's private property. or not place them at the coordinates you've given in your listings. or ...
... or place them legally at the Google coordinates and see comments come back about them being "spot on".
Not that I think your alternative suggestions lack merit, of course.
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no, you can't use google maps/earth to place caches.
On the evidence of my own hides, I'd say yes you can.
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I suggest another size category called the Quark.
You've done that series too? A good leg-stretch, but I thought having only eight caches was a bit miserly.
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Corrdinates from GPSr compared with Google Earth coordinates
in General geocaching topics
Posted
Do you happen to know what alignment accuracy Google would regard as acceptable in the U.S. and Europe?
Also, since you "understand rather well how Google Earth and related processes work" and "this thread is full of bad science", perhaps you could give us some further information about how the mapping process works in practice and what some of the common sources of errors are.