What are acceptable coordinates?

1.1k · February 4, 2011

Exactly how accurate must the coordinates be when hiding a geocache? Is being **.001' or **.002' off on the lat. or long. okay? Sometimes, either one of my two GPSr's don't give me the same reading twice. I've had some geocachers tell me my co-ords for a specific cache are spot on while others say either latitude or longitude is incorrect. What's the rule-of-thumb? Thank you. Regards.

6.7k · February 4, 2011

My rule of thumb is to do the best I can and not worry about it. If one or two finders think it is off a few feet no big deal. If everyone says it is off I check it out.

19k · February 4, 2011

The only real answer I can give you would be, "as accurate as possible". Accuracy will vary both by place (buildings, mountains, and ravines can raise havoc with GPS readings) and time of day (the satellite configuration for where you are varies). But if you are using a good, modern GPS and just take a little time for it to settle in before taking your reading, you should be fine. I generally test mine several times by walking away, selecting the marked waypoint, and following the GPS back to ground zero. Repeat until satisfied.

3.8k · February 4, 2011

My rule of thumb is to do the best I can and not worry about it. If one or two finders think it is off a few feet no big deal. If everyone says it is off I check it out.

I disagree.. worry about it, but just a little. You can debate all day about good caches and bad caches but the bottom line is, a cache with bad coordinates is a terrible cache.

If your GPS does not have an average function, attempt to do some averaging on your own. Not hard to do.

7k · February 4, 2011

it's not really accurate, but to keep it simple you can think of a difference of .001 minutes as about 1.5 meters off.

11.2k · February 4, 2011

I try to get an average of about 100 readings before submitting cache coordinates.

18.9k · February 4, 2011

The general accuracy of our handheld units runs between about 15 and 25 feet. You just aren't going to get more accurate than that except by accident occasionally. Thats around .002 to .005 of a minute.

Anybody that would complain about finding the cache less than 40 foot or so from your coordinates doesn't understand.

5.3k · February 4, 2011

The guidelines imply that you should post the best coordinates you can obtain. Don't artificially alter the coordinates in a misguided attempt to make the cache "more challenging."

February 4, 2011

Listen to Fizzy he's a wealth of knowledge.

3.4k · February 4, 2011

I'm working on hiding a puzzle cache where the solution will give the coordinates and have been to the final location 3 times 4 times, each time averaging about 20-30 readings, and have gotten 4 different sets of coordinates. The latitude readings have ranged from .xx1 to .xx3; the longitude readings from .xx5 to .xx9. I plan to go once more, then just choose something that's in the range of all of them. Then I can finish the questions to be answered to get the solution I decide on.

Do the best you can, and realize that different people at different times with different equipment will get different readings.

February 4, 2011

I have hidden a few caches and I too get all sorts of comments.

"Spot on" or "your coords put me inside the building"

I do use the waypoint averaging on my Garmin to get it as accurate as possible.

If I get several notes about my coords I will check them.

Or when I get a note from mtn-man asking if my cache really is in the middle of the Indian Ocean....

February 4, 2011

The general accuracy of our handheld units runs between about 15 and 25 feet. You just aren't going to get more accurate than that except by accident occasionally. Thats around .002 to .005 of a minute.

Anybody that would complain about finding the cache less than 40 foot or so from your coordinates doesn't understand.

we do understand. we also understand that each gps has a tolerance. say gps a is at one end of its tolerance and gps b trys to find the cache hidden by gps a and b is at the end of their tolerance. now we are adding tolerances and it could now be 50+ ft off.

as well as if it was hidden by an old gps or on a bad reception day. this could make it better or worse.

do your best to get good coords. ask here. learn about your gps. mayb find a local cacher to help you in person if you are intimidated by all this. someone who has hides under their belt. no harm in asking for help.

we have been planning our first hides for the spring. the one i have gotten great coords for on dif days as well as dif weather. the other one i cannot seem to get good for the life of me. the location would be obvious when you got there, but to me that is not good enough. mayb i will have to ask for help on that one. i am using a 62s with the averaging feature.

Monty

February 4, 2011

The general accuracy of our handheld units runs between about 15 and 25 feet. You just aren't going to get more accurate than that except by accident occasionally. Thats around .002 to .005 of a minute.

Anybody that would complain about finding the cache less than 40 foot or so from your coordinates doesn't understand.

we do understand. we also understand that each gps has a tolerance. say gps a is at one end of its tolerance and gps b trys to find the cache hidden by gps a and b is at the end of their tolerance. now we are adding tolerances and it could now be 50+ ft off.

as well as if it was hidden by an old gps or on a bad reception day. this could make it better or worse.

do your best to get good coords. ask here. learn about your gps. mayb find a local cacher to help you in person if you are intimidated by all this. someone who has hides under their belt. no harm in asking for help.

we have been planning our first hides for the spring. the one i have gotten great coords for on dif days as well as dif weather. the other one i cannot seem to get good for the life of me. the location would be obvious when you got there, but to me that is not good enough. mayb i will have to ask for help on that one. i am using a 62s with the averaging feature.

Monty

If there is a spot nearby where you get a good signal you might consider making it an off set cache.

February 4, 2011

The only real answer I can give you would be, "as accurate as possible". Accuracy will vary both by place (buildings, mountains, and ravines can raise havoc with GPS readings) and time of day (the satellite configuration for where you are varies). But if you are using a good, modern GPS and just take a little time for it to settle in before taking your reading, you should be fine. I generally test mine several times by walking away, selecting the marked waypoint, and following the GPS back to ground zero. Repeat until satisfied.

I do the same procedure to mark our caches and that seems to work very well. I hold the gps right over the cache and mark it.

I thought it was pretty interesting when I went to a park event and they were using flags to mark the same coords. Everyone used the same coords to Zero out and they stuck a flag in the ground. A lot of flags in about a 15 ft circle. So I say as long as your within 12-15ft your good.

38.2k · February 5, 2011

My rule of thumb is to do the best I can and not worry about it. If one or two finders think it is off a few feet no big deal. If everyone says it is off I check it out.

Exactly. Even if you rented a $10,000 commercial GPS with centimeter accuracy, the GPS of the searchers will still have that 10-30 ft margin of error and will rarely be dead on your cache.

Coordinates are like horseshoes and hand grenades. If they are close enough they get the job done.

February 5, 2011

I am new at hiding caches and actually have only 2 published so far but I have several in the making. I have been lurking around (in the forum) for a while and my hunting team has a 100 or so logged finds so I am not a total newbie.

That said, I was also having a great deal of "pin Pointing" issues with several GPS's. (Iphone, Magellan Crossover, gps on my ATT Solstice and a Magellan 1400t). Every one gives a different pinpoint and every re-do, results in different numbers each time.

I found the GPS Map conversion website and checked my coordinates with that and found them to be very accurate so far. It is FAR easier to spot the location on the internet map and read then convert the coordinates than trying to get multiple readings from my various GPS sources. I use GPS Coordinate Map. This may be old news but I didn't see any mention of it in this thread. I use the "hybrid" view and seems to work terrific. (So Far) This website and my Magellan Crossover (outdoor mode) are almost identical each time I have checked..

Edited February 5, 2011 by BBDawg

6.7k · February 5, 2011

My rule of thumb is to do the best I can and not worry about it. If one or two finders think it is off a few feet no big deal. If everyone says it is off I check it out.

I disagree.. worry about it, but just a little. You can debate all day about good caches and bad caches but the bottom line is, a cache with bad coordinates is a terrible cache.

If your GPS does not have an average function, attempt to do some averaging on your own. Not hard to do.

Like I said. Do the best you can and don't worry about it. If you honestly did the best you can you HAVE averaged coordinates, either with your GPS or by doing a bit of simple math. I stand by what I said. Let's face it, there are people who will complain if they find your cache three feet from where their GPS said it should be.

February 5, 2011

Squirt and I use a Garmin Oregon and a Colorado and we never have the same ground zero.

We have found the best this for us is when we get readings within 20 feet we hang the unit on our belt loop and start looking.

I think it is called GeoSense :rolleyes:

18.9k · February 5, 2011

I am new at hiding caches and actually have only 2 published so far but I have several in the making. I have been lurking around (in the forum) for a while and my hunting team has a 100 or so logged finds so I am not a total newbie.

That said, I was also having a great deal of "pin Pointing" issues with several GPS's. (Iphone, Magellan Crossover, gps on my ATT Solstice and a Magellan 1400t). Every one gives a different pinpoint and every re-do, results in different numbers each time.

I found the GPS Map conversion website and checked my coordinates with that and found them to be very accurate so far. It is FAR easier to spot the location on the internet map and read then convert the coordinates than trying to get multiple readings from my various GPS sources. I use GPS Coordinate Map. This may be old news but I didn't see any mention of it in this thread. I use the "hybrid" view and seems to work terrific. (So Far) This website and my Magellan Crossover (outdoor mode) are almost identical each time I have checked..

What makes you think the map is more accurate than your GPS?? Most are not. Many have a published accuracy around 45 feetor greater at well known locations. About any GPS unit can do better.

If your GPS does not have an average function, attempt to do some averaging on your own. Not hard to do.

Averaging doesn't always work very well. Consider the following:

Poor Sat geometry and poor signals - You just Average bad data
Great geometry and strong signals - really no need to average
So-so geometry and signal strength - Averaging may or may not yield better coordinates

6.7k · February 5, 2011

I am new at hiding caches and actually have only 2 published so far but I have several in the making. I have been lurking around (in the forum) for a while and my hunting team has a 100 or so logged finds so I am not a total newbie.

That said, I was also having a great deal of "pin Pointing" issues with several GPS's. (Iphone, Magellan Crossover, gps on my ATT Solstice and a Magellan 1400t). Every one gives a different pinpoint and every re-do, results in different numbers each time.

I found the GPS Map conversion website and checked my coordinates with that and found them to be very accurate so far. It is FAR easier to spot the location on the internet map and read then convert the coordinates than trying to get multiple readings from my various GPS sources. I use GPS Coordinate Map. This may be old news but I didn't see any mention of it in this thread. I use the "hybrid" view and seems to work terrific. (So Far) This website and my Magellan Crossover (outdoor mode) are almost identical each time I have checked..

How much difference is there in your readings? I'd be willing to bet that if you average what you get you will be more than close enough. Remember, this is not a pinpoint proposition.

7.5k · February 5, 2011

My rule of thumb is to do the best I can and not worry about it. If one or two finders think it is off a few feet no big deal. If everyone says it is off I check it out.

I disagree.. worry about it, but just a little. You can debate all day about good caches and bad caches but the bottom line is, a cache with bad coordinates is a terrible cache.

If your GPS does not have an average function, attempt to do some averaging on your own. Not hard to do.

Like I said. Do the best you can and don't worry about it. If you honestly did the best you can you HAVE averaged coordinates, either with your GPS or by doing a bit of simple math. I stand by what I said. Let's face it, there are people who will complain if they find your cache three feet from where their GPS said it should be.

I agree with what everyone has said so far:

do the best you can
average your coordinates
if one or two finders think it is a little off no big deal. If everyone says it is off, double check it.

I would add:

provide a good hint so even if it's a little off people will be able to find it with the hint.

Recently I've started adding: "Averaged 100 times with a Garmin 60Cx" to our cache descriptions.

38.2k · February 5, 2011

You can spend days trying to get nearly precise coordinates or you can get perfectly functional coordinates in 1 minute. The difference between the two will likely be a matter of a few feet. The question is, are people finding your cache with minimal complaints? If they are then your coordinates are spot on perfect.

February 5, 2011

for the one i am having troubles with i am from 80-110 ft off. to me that is not acceptable. will try again and again til i am acceptablly happy.

a hint would work, but that is not how we want this one. there is a concrete building nearby(40ft) that is 1 story tall that might be playing a role in the bad coords i am getting. will try at dif times of the day next. been trying from 10am-3pm. 5 times so far.

still got time. so will take the advice here and see what i come up with.

for us, i just passed 300 and my gf is just under 200 finds) we have found all kinds of coords. most are within 15ft (i would say 50%), but have had some that are 40. we usually dont say anything unless its been mentioned in previous logs or it is along ways off. heck out 2 gps units (her explorist GC and my 62s) have been the same and dif(by 25ft) at times. geosense definitely helps as does some patience and reality check. why are we out here and are we in a rush?

Monty

February 5, 2011

You can spend days trying to get nearly precise coordinates or you can get perfectly functional coordinates in 1 minute. The difference between the two will likely be a matter of a few feet. The question is, are people finding your cache with minimal complaints? If they are then your coordinates are spot on perfect.

Yes. What he said!

February 5, 2011

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How much difference is there in your readings? I'd be willing to bet that if you average what you get you will be more than close enough. Remember, this is not a pinpoint proposition.

I should have stated that I did do averaging and what I arrived at was almost exactly what I got from the coordinate map within just a few minutes. MY hides are in relatively well developed areas and there is good resolution on the Google Maps of our area, SO, (so far) I feel pretty comfortable taking a couple of readings at the location, then spotting the location on the map and then throw a dart at the two. I am sure, in time, I will gain a lot of insight from those who find my (future) caches.

22k · February 5, 2011

for the one i am having troubles with i am from 80-110 ft off. to me that is not acceptable. will try again and again til i am acceptably happy.

Hey mHm. What type of gps do you have and what is your Map datum set to: WGS 84?

15.3k · February 5, 2011

If you aren't sure your coordinates are accurate enough, then test them. Enter them into your GPSr and approach the site from at least 100 feet away. Then approach the site a couple more times from different directions. The arrow should take you to the cache no matter which direction you approach from. If it does, then your coordinates are accurate enough.

If you want to be doubly sure, then come back the next day and test them again when the satellite geometry is different.

2.2k · February 5, 2011

Anybody that would complain about finding the cache less than 40 foot or so from your coordinates doesn't understand.

40 feet is a rule of thumb I hear a lot on the forums. I fully understand that with a 15 foot accuracy for each unit you could have a good 30 foot variance between hider and seeker.

However, I think 40 feet (12m) may have been "more" true in the era when everyone was running around with eTrex Legends. Around here I find caches are consistently within 3-5m of where I zero out. I get suspicious when it gets out in the 5-10m range. Anything beyond 10m and I think you have a problem. (Naturally it depends on the terrain -- in the canyons of downtown or under a heavy canopy the acceptable difference is must different.)

Defining "good" coordinates also depend on the cache and the location. A micro in a large spruce tree? Your coordinates should at least get me to the right side of the tree. In a parking lot as long as you get me close to the lamp post I'm happy. :laughing:

Most of the caches I come across now where I find the coordinates are really "out" tend to old caches hidden with old hardware or really new caches hidden with smartphones or by new hiders.

As others said -- if one or two people complain about your coordinates you're OK. If the logs start coming in consistently saying you're "off" you might want to check it out.

As others said

3k · February 5, 2011

clip

How much difference is there in your readings? I'd be willing to bet that if you average what you get you will be more than close enough. Remember, this is not a pinpoint proposition.

I should have stated that I did do averaging and what I arrived at was almost exactly what I got from the coordinate map within just a few minutes. MY hides are in relatively well developed areas and there is good resolution on the Google Maps of our area,

The resolution of Googles, or Bing, or whoevers, maps is totally irrelevant. They could provide a resolution so fine that it would let you read the newspaper somebody was reading in a screen shot - but what guarantee have you got that their positional accuracy is any good?

The maps you see online are just pictures - if the provider hasn't positioned them accurately in the first place what good are they?

7k · February 5, 2011

However, I think 40 feet (12m) may have been "more" true in the era when everyone was running around with eTrex Legends. Around here I find caches are consistently within 3-5m of where I zero out. I get suspicious when it gets out in the 5-10m range. Anything beyond 10m and I think you have a problem. (Naturally it depends on the terrain -- in the canyons of downtown or under a heavy canopy the acceptable difference is must different.)

Fully agree. The argument that both the hider's and the seeker's inaccuracy can be up to 6 meters and thus the coords can be off by up to 12 meters is kinda bogus. One reason is that the hider can use averaging to significantly lower his own inaccuracy. With only a short time of averaging, you can get your coordinates down to 1-2 meters accuracy, especially if you have a WAAS/EGNOS lock, in which case your accuracy is higher to begin with. The seeker obviously can't use averaging as they're moving.

The other reason is that accuracy is 2-dimensional, so while it is possible that the hider's coordinates were of by some amount in one direction and the seeker has his coordinates off in exactly the opposite direction, most likely this is not what happens. It's much more likely that the seeker has his coords off into some other direction and so the difference between the two coordinate pairs won't be as much. Since accuracy is just an estimate of probability/likelihood and not a guarantee, this fact has to be taken into account and simply adding up the two accuracy numbers is not how it works.

18.9k · February 5, 2011

However, I think 40 feet (12m) may have been "more" true in the era when everyone was running around with eTrex Legends. Around here I find caches are consistently within 3-5m of where I zero out. I get suspicious when it gets out in the 5-10m range. Anything beyond 10m and I think you have a problem. (Naturally it depends on the terrain -- in the canyons of downtown or under a heavy canopy the acceptable difference is must different.)

Fully agree. The argument that both the hider's and the seeker's inaccuracy can be up to 6 meters and thus the coords can be off by up to 12 meters is kinda bogus. One reason is that the hider can use averaging to significantly lower his own inaccuracy. With only a short time of averaging, you can get your coordinates down to 1-2 meters accuracy, especially if you have a WAAS/EGNOS lock, in which case your accuracy is higher to begin with. The seeker obviously can't use averaging as they're moving.

The other reason is that accuracy is 2-dimensional, so while it is possible that the hider's coordinates were of by some amount in one direction and the seeker has his coordinates off in exactly the opposite direction, most likely this is not what happens. It's much more likely that the seeker has his coords off into some other direction and so the difference between the two coordinate pairs won't be as much. Since accuracy is just an estimate of probability/likelihood and not a guarantee, this fact has to be taken into account and simply adding up the two accuracy numbers is not how it works.

What I find funny about these statements is that my old etrex Legend with a clear view of the sky was is every bit as accurate as my newest units. Rated as low as 3m with a WAAS lock. I know because I have sat them side by side a number of times and compared readings.

Just the other day, I saw a report that new super accurate multiple site GPS readings show that the North American contenintal plate is moving just over 3 inches a year to the west south west. In addition, some of the larger fault lines across the US move as much as 8" per year in varying directions. That got me thinking that some of the oldest caches could have moved as much as 80" off of the spot - even assuming that thier coordinates were 100% perfect to begin with. Now they are 6+ foot off. Another 20 to 30 years of caching and some caches could be waaaay off. (maybe I am just thinking too much) :rolleyes:

February 5, 2011

I just average a reading on the GPS, make a few approaches to see if I get to the area... then before posting to the site I throw them into google maps just to make sure I didn't copy a number down wrong and am in the right area. It's not perfect but it will tell you if you got anything but the last number incorrect.

7k · February 6, 2011

Just the other day, I saw a report that new super accurate multiple site GPS readings show that the North American contenintal plate is moving just over 3 inches a year to the west south west. In addition, some of the larger fault lines across the US move as much as 8" per year in varying directions. That got me thinking that some of the oldest caches could have moved as much as 80" off of the spot - even assuming that thier coordinates were 100% perfect to begin with. Now they are 6+ foot off. Another 20 to 30 years of caching and some caches could be waaaay off. (maybe I am just thinking too much)

Not at all, there's actually a virtual around here that deals with this very subject: http://coord.info/GC8535

These days I assume it could've been published as an earthcache (with some frivolous logging requirements).

3.3k · February 6, 2011

for the one i am having troubles with i am from 80-110 ft off. to me that is not acceptable. will try again and again til i am acceptablly happy.

a hint would work, but that is not how we want this one. there is a concrete building nearby(40ft) that is 1 story tall that might be playing a role in the bad coords i am getting. will try at dif times of the day next. been trying from 10am-3pm. 5 times so far.

still got time. so will take the advice here and see what i come up with.

for us, i just passed 300 and my gf is just under 200 finds) we have found all kinds of coords. most are within 15ft (i would say 50%), but have had some that are 40. we usually dont say anything unless its been mentioned in previous logs or it is along ways off. heck out 2 gps units (her explorist GC and my 62s) have been the same and dif(by 25ft) at times. geosense definitely helps as does some patience and reality check. why are we out here and are we in a rush?

Monty

I hesitate to ask, but if you have not found the cache how do you know you are 80-110 ft. off? Is that what your GPSr is suggesting the EPE might be?

1.5k · February 6, 2011

I agree with the folks that take several readings by walking away and then back to the hiding spot and then averaging those to get the best one can, then not worrying about it unless you get comments about the coords being off.

We have found caches where our GPSr says it is 40 or 50 feet off. Once or twice I have (just as an experiment) walked away and came back to the hide and found the coords were now only 15 feet off! My point is that if you search a cache and find the coords are off, maybe it isn't the cache, but your unit at that particular time!

This isn't an exact science with our consumer grade GPSrs no matter how proud we may be of them! Sometimes they are just off!

Before I were ever to complain about readings being 40 feet off, I'd want to make darned sure my unit was at the top of it's form, on a clear day, with all the sats locked in ... and even then I wouldn't complain! It would be really boring if my GPSr put me right on the cache every time, with no hunting involved at GZ. What challenge would that be?

We will never get to where all the GPSrs agree all the time and put us within 2 or 3 feet all the time!

7k · February 6, 2011

We have found caches where our GPSr says it is 40 or 50 feet off. Once or twice I have (just as an experiment) walked away and came back to the hide and found the coords were now only 15 feet off! My point is that if you search a cache and find the coords are off, maybe it isn't the cache, but your unit at that particular time!

This is very true, and it helps to know the limitations of your GPS and how it behaves for those cases. For example with a modern receiver, if you're out in the open, have a WAAS lock and it shows you an accuracy of 3 meters, then it's not likely to be suddenly 10 meters off, while in a canyon or in a thick forest, the same unit can behave quite differently and it could be just as you describe.

2.2k · February 6, 2011

What I find funny about these statements is that my old etrex Legend with a clear view of the sky was is every bit as accurate as my newest units. Rated as low as 3m with a WAAS lock. I know because I have sat them side by side a number of times and compared readings.

I agree -- the big thing being "with a clear view of the sky". Under less than ideal circumstances (tree cover, or being inside a bar at a caching event :lol: ) my [now aging] 60CSx will outperform my old Legend big time.

3.2k · February 6, 2011

I am new at hiding caches and actually have only 2 published so far but I have several in the making. I have been lurking around (in the forum) for a while and my hunting team has a 100 or so logged finds so I am not a total newbie.

That said, I was also having a great deal of "pin Pointing" issues with several GPS's. (Iphone, Magellan Crossover, gps on my ATT Solstice and a Magellan 1400t). Every one gives a different pinpoint and every re-do, results in different numbers each time.

I found the GPS Map conversion website and checked my coordinates with that and found them to be very accurate so far. It is FAR easier to spot the location on the internet map and read then convert the coordinates than trying to get multiple readings from my various GPS sources. I use GPS Coordinate Map. This may be old news but I didn't see any mention of it in this thread. I use the "hybrid" view and seems to work terrific. (So Far) This website and my Magellan Crossover (outdoor mode) are almost identical each time I have checked..

Many on these forums will not agree with you, but if you are able to interpret the maps accurately you can get good coordinates by this method. Field checking with a GPS will confirm their accuracy and eliminate the need for multiple trips and averaging a bunch of data. Before the flaming starts I realize the accuracy differs in certain areas and of course is not linked in any way to the map reading ability of those that live in those areas.

Edit.. I've cached in the Orlando/Tampa area and found the maps to be accurate there.

Edited February 6, 2011 by edscott

18.9k · February 6, 2011

What I find funny about these statements is that my old etrex Legend with a clear view of the sky was is every bit as accurate as my newest units. Rated as low as 3m with a WAAS lock. I know because I have sat them side by side a number of times and compared readings.

I agree -- the big thing being "with a clear view of the sky". Under less than ideal circumstances (tree cover, or being inside a bar at a caching event ) my [now aging] 60CSx will outperform my old Legend big time.

That is the difference the newer units give you, better performance and accuracy under less than ideal conditions - the ability to drag in even a weak sat signal. But with a clear view of the sky, those older units work equally well.

February 7, 2011

When we decided to start hiding caches, it took us a few days.

First we took coordinates at different times of day and tested each with the walk away method.

At one point we brought a friend it with a different GPSr to check as well.

In the end, we decided we tried our best with a reasonable and diligent effort.

However, to remove as much doubt as possible we made sure we gave really good clues.

Most of our caches even give a warning in the description that the hint may lean towards being a spoiler.

Happy Geocaching! - hawkeyetob

5.7k · February 7, 2011

We use the "Average waypoint" function on our GPSr. On the Garmin 60CSx, we normally let it take around 50 readings to let it settle in. On the Oregon 400t, we let it go until it has 100% on the progress bar.

Other GPS receivers have waypoint averaging built in, perhaps by a different name. The more folks who use it, the better.

18.9k · February 7, 2011

We use the "Average waypoint" function on our GPSr. On the Garmin 60CSx, we normally let it take around 50 readings to let it settle in. On the Oregon 400t, we let it go until it has 100% on the progress bar.

Other GPS receivers have waypoint averaging built in, perhaps by a different name. The more folks who use it, the better.

Before you spend too much time on Averaging - might read: http://garmin.blogs.com/softwareupdates/2009/04/waypoint-averaging.html

February 8, 2011

Our last placement was an LPC where I took one reading, then went home for a container and preped the cache page. Upon return checked that the original coords were horseshoe/hand grenade accurate. Then submitted the cache report. All finders have not had a problem with it.

On another location I averaged for several minutes, then used that to renavigate to the spot when I returned with the container, the averaged somemore for the published coords.

3.3k · February 8, 2011

We use the "Average waypoint" function on our GPSr. On the Garmin 60CSx, we normally let it take around 50 readings to let it settle in. On the Oregon 400t, we let it go until it has 100% on the progress bar.

Other GPS receivers have waypoint averaging built in, perhaps by a different name. The more folks who use it, the better.

Before you spend too much time on Averaging - might read: http://garmin.blogs....-averaging.html

Thanks for the excellent link StarBrand! The article pretty much reinforces the way have gone about arriving at coordinates for our caches in challenging locations. We take coordinates on at least three or four days and at different times of day, then blend the coordinates to settle on the ones to post.

February 8, 2011

for the one i am having troubles with i am from 80-110 ft off. to me that is not acceptable. will try again and again til i am acceptably happy.

Hey mHm. What type of gps do you have and what is your Map datum set to: WGS 84?

i have a 62s and it is set to WGS 84.

i am hoping to get back out later this week when the temps warm up from 0 to try again. i just do not get that it is that far off. if i had not gotten spot on at another location i would not think much of it.

Monty

February 8, 2011

for the one i am having troubles with i am from 80-110 ft off. to me that is not acceptable. will try again and again til i am acceptablly happy.

a hint would work, but that is not how we want this one. there is a concrete building nearby(40ft) that is 1 story tall that might be playing a role in the bad coords i am getting. will try at dif times of the day next. been trying from 10am-3pm. 5 times so far.

still got time. so will take the advice here and see what i come up with.

for us, i just passed 300 and my gf is just under 200 finds) we have found all kinds of coords. most are within 15ft (i would say 50%), but have had some that are 40. we usually dont say anything unless its been mentioned in previous logs or it is along ways off. heck out 2 gps units (her explorist GC and my 62s) have been the same and dif(by 25ft) at times. geosense definitely helps as does some patience and reality check. why are we out here and are we in a rush?

Monty

I hesitate to ask, but if you have not found the cache how do you know you are 80-110 ft. off? Is that what your GPSr is suggesting the EPE might be?

i am getting coords for a hide. the one location i used my 62s for to average coords shows me withing 2 ft after multiple attempts. this 2nd location i cannot get close at all after averaging. i average and then go back to that point and i am 80-110 ft off. odd that one location is spot on and the other is not close enough to say good to go.

will try again. doesnt help that i am new to gps and to caching, but dang it i am not gonna let this win. i will figure it out

Monty

7k · February 8, 2011

Did you maybe turn the GPS on only shortly before starting the averaging?

February 8, 2011

5 minutes or so before. i turned it on enroute to the location.

Monty

2.1k · February 9, 2011

We have found caches where our GPSr says it is 40 or 50 feet off. Once or twice I have (just as an experiment) walked away and came back to the hide and found the coords were now only 15 feet off!

One day I was searching for a cache in a tree. It was winter, there were no leaves on the tree, and not a cloud in the sky. My GPS said I was 3' from GZ. I looked in the tree for a few minutes, then glanced at my GPS and it said I was 90' West of GZ. I was stunned. Then I noticed that the number was changing; I watched as it gradually, over about three minutes, dropped back to three feet.

And it wasn't just my receiver; another cacher was there and his smart phone did the same thing as my Garmin.

What are acceptable coordinates?

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