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Satellites Hate My Neighborhood, I Guess


angiem357
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Hi, cachers. I know this subject has been touched on before, but I haven't found any threads with my specific issue.

 

I recently moved to a new city, so I'm placing my front yard cache at my new place. Problem is, every app, online map, or GPS coordinate identifier is coming up with different coords and locations; some of them are very clearly too far off to even attempt to publish. I mean, like, backyard, two houses down, house behind mine on a different street. I've tried 5 so far, and none of them come close to where it belongs. I've dropped the device and left it alone for a few minutes to see if it would even out; no dice. I've cross-referenced some; I drop a waypoint and then use those coords in cgeo or the Geocaching app and none of them match up with any acceptable distance.

 

Truthfully, this is a pretty easy cache so if it's even 20 feet off, I'm sure most people would walk right up to it, but still. What do I do if this continues? What do y'all feel is an acceptable level of inaccuracy? My tolerance is a lot higher than most, I think, because I want the challenge of actually *looking,* but I've read some really rude logs from others when the coords are off on others' caches. I don't want to make people mad.

 

All my caching buddies are back home, otherwise I'd work on it with them. :(

 

Thanks in advance and, if you've gotten this far, I applaud you.

 

- AngieM357

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Sounds like you're using a phone. Is it set to use the built-in GPS chip, or just the cellular network? The latter would certainly explain your problems. (This is why phones have been tarred-and-feathered in the forums for years as a means for placing caches. They've gotten better, but still...)

 

Do you have access to a dedicated GPS unit? Using that, combined with the waypoint averaging feature, would be ideal.

 

PS, satellite imagery can sometimes be out to lunch for accuracy. Never use it to fine-tune a cache's coords.

Edited by Viajero Perdido
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Sounds like you're using a phone. Is it set to use the built-in GPS chip, or just the cellular network? The latter would certainly explain your problems. (This is why phones have been tarred-and-feathered in the forums for years as a means for placing caches. They've gotten better, but still...)

 

Do you have access to a dedicated GPS unit? Using that, combined with the waypoint averaging feature, would be ideal.

 

PS, satellite imagery can sometimes be out to lunch for accuracy. Never use it to fine-tune a cache's coords.

 

I've used both methods with a phone, a GPS unit that is probably 15 years old which may or may not be working correctly, and satellite off of three different sites using my desktop and dropping a pin. Even my regular street address in maps is coming up wrong. What I was saying before is that I have tried to see if any of the coords are matching up with each other, and while several are, those are still pointing to the middle of the street, two houses down.

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Oh, I'd also like to mention that I have tried using the Geocaching and cgeo apps to see what THEY say my coordinates are while I'm standing there. I figure most people use those apps to locate caches, so I might as well try to see where they think I'm standing. Again, coords were totally off and they didn't agree as to where I was, either. Regardless of what some systems say, people really do seem to go off the apps so it makes sense to take that into consideration as well. Oddly enough, I haven't had problems with this in other places; just here at my new house.

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A few random thoughts:

 

When the apps are reporting you're co-ordinate position they're just telling you what the GPS in the phone is reporting, so the numbers you see aren't dependent on the app.

 

When you say "the co-ords are way off" "pointing into the middle of the street two doors down" do you mean that the co-ords reported by your GPS/phone, when displayed on a map don't show up in your yard? Bear in mind that maps are often way out, google maps can be up to 100m off in some locations, while being spot on in others. I would trust my GPS (Etrex30) over an online map any time.

 

Do you know how many satellites you have in your "constellation"? The more satellites you have the better the accuracy should be. You should be able to get a satellite display on your GPS to show you how many it is locked on to. On your android phone install "GPS tools" it will also allow you to see how many satellites it is locked onto.

 

I would expect my original, first gen Etrex to be correct to within about 30 feet, I expect my Etrex30 and Android phone to be correct to within about 10-15 feet.

 

I would say if you take your phone and GPS and place them together, leave them to settle for a couple of minutes, then check the co-ords they're reporting, if those co-ords are within 20feet of each other then they're probably working fine and can be relied on. Bear in mind that atmospheric conditions etc. can cause variations on different days.

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I've used both methods with a phone, a GPS unit that is probably 15 years old which may or may not be working correctly, and satellite off of three different sites using my desktop and dropping a pin.

 

By "satellite", it sounds like you mean satellite images, not GPS. As I said, do not trust the accuracy of satellite images. GPS only. And that's GPS via satellites, not a cellphone using just cell-tower triangulation. (Your brand of phone operating system will determine the terminology.)

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I've used both methods with a phone, a GPS unit that is probably 15 years old which may or may not be working correctly, and satellite off of three different sites using my desktop and dropping a pin.

 

By "satellite", it sounds like you mean satellite images, not GPS. As I said, do not trust the accuracy of satellite images. GPS only. And that's GPS via satellites, not a cellphone using just cell-tower triangulation. (Your brand of phone operating system will determine the terminology.)

I meant both.

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A few random thoughts:

 

When the apps are reporting you're co-ordinate position they're just telling you what the GPS in the phone is reporting, so the numbers you see aren't dependent on the app.

 

When you say "the co-ords are way off" "pointing into the middle of the street two doors down" do you mean that the co-ords reported by your GPS/phone, when displayed on a map don't show up in your yard? Bear in mind that maps are often way out, google maps can be up to 100m off in some locations, while being spot on in others. I would trust my GPS (Etrex30) over an online map any time.

 

Do you know how many satellites you have in your "constellation"? The more satellites you have the better the accuracy should be. You should be able to get a satellite display on your GPS to show you how many it is locked on to. On your android phone install "GPS tools" it will also allow you to see how many satellites it is locked onto.

 

I would expect my original, first gen Etrex to be correct to within about 30 feet, I expect my Etrex30 and Android phone to be correct to within about 10-15 feet.

 

I would say if you take your phone and GPS and place them together, leave them to settle for a couple of minutes, then check the co-ords they're reporting, if those co-ords are within 20feet of each other then they're probably working fine and can be relied on. Bear in mind that atmospheric conditions etc. can cause variations on different days.

None of the coordinates on any device, app, or map are being reported as correct. If I cross-reference any of them, my location - and I mean, within 20 feet at least - is not close to correct. I have used GPS Tools as well as two other GPS apps for the phone part. I've had the best luck with GPS Essentials in the past, but I try them all just to see what coincides. There have been some small clouds here and there but the number of available vs used satellites has been variable all day.

 

As I said, I have never before had this issue until I got to this location. Five miles away, no problem. Back in Houston, no problem. It doesn't seem scientifically sound to say that there's something weird going on right in this area, but that's what my wild imagination is thinking!

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I don't see a problem. You have not told us what devices you are using (brand and model). You have not described you present location (flat open area, heavily forested, tall buildings, adjacent steep hill, etc). You have not told us why you think readings are "incorrect." You have not described how you are testing your devices. Different devices can give different readings even when set side by side.

 

Have you tried obtaining and recording a reading, then using the same device to navigate to that location the next day?

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GeoTrekker26 is right - there's a lot of bad science here. Additionally, the placement guidelines https://www.geocaching.com/about/guidelines.aspx require you to "obtain the coordinates with a GPS device" - not guessing where a pin drops on a map or using a phone. Please place geocaches only using an actual working GPS.

 

As a seeker, I generally dread caches placed in yards because even tens of feet of disagreement - which is common even with real GPSes - can mean you're digging in the wrong shrubs and get to explain geocaching to a homeowner while the police are on the way for suspicious shrubbery fondling.

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"obtain the coordinates with a GPS device" - not guessing where a pin drops on a map or using a phone. Please place geocaches only using an actual working GPS.

 

Uhhh... In general I agree, except for the part where you are saying that phones are not GPS devices. If a phone is GPS enabled, it IS a GPS device.

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"obtain the coordinates with a GPS device" - not guessing where a pin drops on a map or using a phone. Please place geocaches only using an actual working GPS.

 

Uhhh... In general I agree, except for the part where you are saying that phones are not GPS devices. If a phone is GPS enabled, it IS a GPS device.

True, but it really depends on the phone and it's age. Early smartphones were bad.

 

My very first smartphone, a Samsung Galaxy S, while equipped with a GPS chip, had pathetic accuracy and was useless for finding caches.

 

My previous smartphone (LG Optimus G) and my current smartphone (Sony Xperia Z3) are just as accurate as my Oregon 600 in most cases.

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Yard caches are fine as long as the description and/or hint are sufficient enough to keep you in the correct yard and the correct part of the yard.

 

Yes. Be specific so there's no worry that the finder ends up in the wrong yard or traipsing through your petunias.

I've been to houses where the owners placed a geocaching banner somewhere very visible, often a prominent window, so that when you drive up you are sure you have the correct house.

Edited by L0ne.R
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You log more DNFs if you fail to read listings and look at attributes.

 

Is what I wrote not clear? MOST people just go and look. When they have trouble, then they read the hint and if that does not help the description and past logs. This has zero affect on the amount of logged DNFs. Owners that do not understand how the average cacher works, create poor caches, IME.

 

Most people do not read the description or hint until they have searched and not found it.
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Most people do not read the description or hint until they have searched and not found it.

Was there a poll?

Would "Many people" be good enough? The argument being made here would be supported by "from my own personal experience, I know that once in a while people..." So I don't think a poll is needed. (Although, personally, I suspect a poll would, in fact, support the claim that more than half the time people look for a cache -- i.e., "most" -- they don't read the description before they start searching.)

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By "satellite", it sounds like you mean satellite images, not GPS. As I said, do not trust the accuracy of satellite images.

The Aggies are safe. At least the GE imagery around the College Station, TX area (where the OP is located) is spot on. Might be a problem where you live, but not there. You'll find the center of the A&M dome nailed pretty much dead nuts.

 

Please do not make blanket statements about the quality of the alignment of overhead imagery. I can't remember the last U.S. city I visited where there was an issue with it.

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...support the claim that more than half the time people look for a cache -- i.e., "most" -- they don't read the description before they start searching.)

That must make 'urban caching' pretty tedious. If we're going to cache 'in town', we go armed with every bit of information on the cache page. It is well nigh IMPOSSIBLE to cache in a major downtown area without added info thanks to view of the sky and plenty of multipath issues. Coordinates often run +/- 200 feet or more. Edited by ecanderson
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I am guessing I read the description about 2% of the time if that. That happens when I haven't found it in the initial search. Even then most descriptions don't have info relevant to the search. Have gone whole days or more without needing it. As to it being so necessary in urban I haven't found that to be true. The coords and hint if there is one seem to be all I need.

 

As to front yard caches when I pull up on my bike (probably 95% plus of my caching is on a bike) and see it is one of those mark it for my ignore list and move on. Just not fond of them.

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I am guessing I read the description about 2% of the time if that. That happens when I haven't found it in the initial search. Even then most descriptions don't have info relevant to the search. Have gone whole days or more without needing it. As to it being so necessary in urban I haven't found that to be true. The coords and hint if there is one seem to be all I need.

 

You might have gotten away with that because of the high amount of traditionals you have done. Won't work for multi's or even traditionals that aren't just grab and go caches. We tend to avoid "simple" trads so not reading listings is asking for trouble.

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Satellite images can be severely "off" in one part of a town, yet spot-on just a few blocks away.

Apart from a goat track somewhere in the boondocks with imagery dating back some years ago, please provide examples. See prior post. Is it really THAT bad up in Canada?

A few years back, west-central Calgary was notably off. River-side caches appeared to be in the middle of the river.

 

I don't have any current examples because I don't use satellite imagery much these days. That doesn't mean there aren't any.

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As to it being so necessary in urban I haven't found that to be true. The coords and hint if there is one seem to be all I need.

I don't think you're thinking of the right "urban". While I don't normally look at the description right away out in the suburbs, when I go caching in San Francisco, my GPSr only gets me within a block of the cache, so the description is often important, although admittedly most times it's the hint that tells me where to look.

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A few years back...

Exactly. "A few years back", the alignment was poor in MANY areas. It's that old history that keeps being brought back to the fore, even after they've done a great deal of work to clean it up. It used to be too far offset in too many places to be of much use. These days, I encourage use of GE as a double check against accidentally posting problematic coordinates when placing caches. Not much help in the woods (one tree looks pretty much the same as all the rest!) but If GZ is actually visible and there's a discrepancy between coordinates to be posted and what you see on GE, it's time go to back and take another set of readings... at least anywhere I've been in recent history.
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As to it being so necessary in urban I haven't found that to be true. The coords and hint if there is one seem to be all I need.

I don't think you're thinking of the right "urban". While I don't normally look at the description right away out in the suburbs, when I go caching in San Francisco, my GPSr only gets me within a block of the cache, so the description is often important, although admittedly most times it's the hint that tells me where to look.

+1 to that, right down to the location. I was at a trade show in SFO in June, and was glad that most of the COs were helping me out a bit with some text. Like any major downtown area with tall buildings, it's a right bugger to get a decent fix. Similarly in the last couple of weeks, caching in downtown Denver posed the same problem. Bad view of the sky + multipath makes for a tough day unless you're armed with a bit of additional information. Sometimes what would otherwise pass for 'the hint' is IN the description.
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As a seeker, I generally dread caches placed in yards because even tens of feet of disagreement - which is common even with real GPSes - can mean you're digging in the wrong shrubs and get to explain geocaching to a homeowner while the police are on the way for suspicious shrubbery fondling.[/color]

 

Quoted for truth. Bolded for :lol:

 

I all but refuse to look for caches in people's yards, apartment complexes, townhouses, etc. for that very reason.

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Are there by any chance major power lines passing the front or back yards that would interfere with gps device reception?

 

Have you by any chance double checked the Garmin street number address range interpolation at your particular location, if route address search feature is used?

Edited by 39_Steps
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