working out the coordinates for your new cache

[+Hayche]

I am currently in the process of hiding my new cache. Went out with it today, nice sunny clear (rather chilly) day. Found the spot I have been working on, hid the cache and set to the task of working out the coordinates. Two different android apps on one device and about half an hours worth of wondering around and sitting still, notes taken and returned home. Plotted them on my memory map software and I am still not happy that any of them are accurate, I seem to be jumping around the area. How do other cache hiders get coordinates that they are happy with? Do you go out with more that one GPS device and compare or two different apps on once device?

 

(Not liking my auto correct on my new tablet either, sorry about the error in the subject)

Edited December 29, 2013 by Hayche

[+Manville Possum]

I use a Garmin GPS GPSmap 60 and average the coordinates. I can get within 7-12 feet of a location with a clear view, even in wooded areas average of 14 feet. I also recheck the coordinates in Google Earth, sometimes. My cell phone only gets me in the general area of around 40 feet. I think somewhere it suggests not to use a smartphone to take coordinates for a geocache placement.

[+The_Incredibles_]

I take maybe 4 different readings over a period of 10 minutes with my android then I average them by hand. If I'm in an area of bad reception like a valley, slope, rock wall, near a building or for other reason, I will give a good hint and likely also put some flagging tape up.

Is yor phone accurate for finding caches? Then it should be good for hiding caches.

[+Hayche]

My phone (HTC Sensation) usually does a fantastic job, both for hiding my last two caches and finding lots. I am just interested in what techniques others have.

[+K13]

Try this: Take a reading to get the coordinates of your location. Write them down, noting the time and date. Repeat this process on a couple of other days at different times. After the last reading, go away and average those coordinates. Enter this average as a waypoint on your device and try to navigate to that point. If this gets you within a suitable distance to your cache placement, all is good and you can feel confident about using that average. Others will suggest using a similar method, walking a few hundred feet away between readings, all in the same day/time.

Personally, I use a GPSr (all my placements were done with my old Magellan) and have never had any complaints with my coords.

Good luck with your cache.

[+Chief301]

I'm glad to see that over time the conversation has turned away from "Never, ever hide a cache with a smartphone" and more toward "If you must use a phone, here's how to get the best results" 😊

 

I'm not familiar with the Android system but iPhone has an app called Perfect Mark which is designed specifically for waypoint averaging, which is what you need. Search the Android marketplace (or whatever they call it) for "Waypoint Averaging" or something along those lines. It will simplify the process a great deal. Then, plan on visiting the site two or three times (on different days if you can) and adding additional samples to that reading. Then check those coordinates by plugging them in to your device and see how close they bring you to the spot.

 

Besides that and the other advice already offered, there's not much more you can do.

[+Hayche]

Thats exactly what i did with my first two and i expect i will make the return trip and hopefully final decision tomorrow. I am very glad to here that i am not one to do a bit of back and forth to check.

[+Hayche]

I'm glad to see that over time the conversation has turned away from "Never, ever hide a cache with a smartphone" and more toward "If you must use a phone, here's how to get the best results"

 

I'm not familiar with the Android system but iPhone has an app called Perfect Mark which is designed specifically for waypoint averaging, which is what you need. Search the Android marketplace (or whatever they call it) for "Waypoint Averaging" or something along those lines. It will simplify the process a great deal. Then, plan on visiting the site two or three times (on different days if you can) and adding additional samples to that reading. Then check those coordinates by plugging them in to your device and see how close they bring you to the spot.

 

 

(I am also glad that this has not turned to a no smart phone app as even if i when back to the OS maps they would be on some sort of smart device I started geocaching with a PDA that did GPS positioning on Memory Maps)

 

Yes, that's what i need, waypoint averaging app. that sounds like a really good idea. i had looked though a few of the geocaching apps looking for place new cache feature, but i did not think to come from that angle. Thanks

Edited December 29, 2013 by Hayche

[+niraD]

If you don't trust your coordinates, then test them out. Enter your coordinates into your device and then use it to navigate to the cache from at least 100ft away. The arrow should point to the cache location as you approach. Then repeat the test, approaching from various directions from at least 100ft away. No matter which direction you approach from, the arrow should point to the cache location as you approach.

 

If it doesn't, then adjust your coordinates and repeat the test until it works.

 

Bonus points for repeating the test at a different time and day, when the GPS satellites are in a different configuration.

[+Sharks-N-Beans]

If you don't trust your coordinates, then test them out. Enter your coordinates into your device and then use it to navigate to the cache from at least 100ft away. The arrow should point to the cache location as you approach. Then repeat the test, approaching from various directions from at least 100ft away. No matter which direction you approach from, the arrow should point to the cache location as you approach.

 

If it doesn't, then adjust your coordinates and repeat the test until it works.

 

Bonus points for repeating the test at a different time and day, when the GPS satellites are in a different configuration.

 

Super double bonus if you have a friend do the test.

[+The_Incredibles_]

 

Yes, that's what i need, waypoint averaging app. that sounds like a really good idea.

 

You don't really need a waypoint averaging app. It's nice to have, but not necessary and can give you less accuracy if you don't use it right. You can do everything you need with a calculator. Ideally, you will take a waypoint, go back another day and time and take another, then return another day and time to take yet another. Not always practical if you're hiding a cache up a hiking trail and certainly unnecessary if you're hiding it in a place with excellent reception, such as in a flat, wide-open area.

 

If I'm hiding a cache up a hiking trail, I will often mark a couple waypoints, go look for other cache, come back and mark a couple more waypoints, then average them.

 

For example, lets looks at these partial coordinates. To average the North, just do (0.920+0.914+0.916+0.924)/4=0.919.

So you get N 48 27.919. I've ignored the 27.950 because it was so far off from the others.

 

N 48° 27.920

N 48° 27.914

N 48° 27.916

N 48° 27.924

N 48° 27.950

Edited December 30, 2013 by The_Incredibles_

[+Heli Leo]

I use a Garmin Montana 600 or a Garmin GPSmap62sc to place the cache and then come back on different days at different times with a Garmin Nuvii 500. a Samsung III Android phone, the 62sc, and the Montana. I approach the cache from different directions with each GPSr. If those four different GPSr get me within 15 feet then I publish the coordinates.

[+Bunya]

<snip>

Bonus points for repeating the test at a different time and day, when the GPS satellites are in a different configuration.

(Emphasis mine.)

 

I think this is a more important point than many geocache placers realise.

The more widely distributed (far apart) the satellites are in the sky the better the accuracy.

If you are taking a reading with the only visible satellites in a line or close together it won't be as accurate.

[+bjohio]

 

For example, lets looks at these partial coordinates. To average the North, just do (0.920+0.914+0.916+0.924)/4=0.919.

So you get N 48 27.919. I've ignored the 27.950 because it was so far off from the others.

 

N 48° 27.920

N 48° 27.914

N 48° 27.916

N 48° 27.924

N 48° 27.950

 

I use this method above and also verify it on Google Maps. Pull up your location on Google Maps. Move your mouse to the location on the map you want the coords for. Right click (control click on a Mac) and select from the menu "What's Here". You get the exact coords from the location. I use this method all the time and have had no complaints about the accuracy (sometimes even a compliment).

[+dprovan]

Move your mouse to the location on the map you want the coords for. Right click (control click on a Mac) and select from the menu "What's Here". You get the exact coords from the location.

You get (in the search bar) coordinates in decimal degrees, right? I always have to use FizzyCalc to convert to degrees/decimal minutes that's required for a cache listing. Does google maps show that format somewhere I'm not noticing?

 

But, to get back on topic, watch out because google maps aren't always aligned with reality. The space views, in particular, can sometimes be way off from actual coordinates. I'm in the SF bay area where things are aligned pretty well, but you still run into newbies using this trick with the default 45° view, which is always way off here. I've noticed that in other area the space view is useless for getting an accurate location measurements.

[+NYPaddleCacher]

For example, lets looks at these partial coordinates. To average the North, just do (0.920+0.914+0.916+0.924)/4=0.919.

So you get N 48 27.919. I've ignored the 27.950 because it was so far off from the others.

 

N 48° 27.920

N 48° 27.914

N 48° 27.916

N 48° 27.924

N 48° 27.950

 

I use this method above and also verify it on Google Maps. Pull up your location on Google Maps. Move your mouse to the location on the map you want the coords for. Right click (control click on a Mac) and select from the menu "What's Here". You get the exact coords from the location. I use this method all the time and have had no complaints about the accuracy (sometimes even a compliment).

 

I noticed that this technique doesn't seem to work with the "new" Google Maps. Right clicking on the map (at least with Chrome) doesn't bring up the pop up window with the "What's Here" link. Clicking on the question mark icon in the lower right portion of the page will bring up a menu with a "Return to classic Google Maps" link, which still has the "What's Here" feature.

 

However, there have been lots of examples posted here which exemplify where satellite imagery is out of sync with the real world. I wouldn't rely on google maps for confirmation that coordinates are accurate.

 

I think it's also worth noting that Geocaching is a global game, but the usefulness of Google maps for capturing coordinates is far from universal. I found a cache in Costa Rica several years ago at this Google Maps location.

 

A couple of years ago the satellite view at that location showed nothing but clouds for a 30 mile radius. If you look at the link above you can see that the imagery is clear, but the resolution would not be good enough to identify the a large tree (at the edge of a steep cliff). You can also see that map tiles to the south that there are a lots of clouds that could obscure a cache location (not too surprising in a rain forest). Just to the north much of the tiles are replaced with "We are sorry, but we don't have imagery for this location at this zoom level."

 

While satellite imagery might be sufficient for capturing lat/long coordinates for most places in North America and Europe, that location shown above demonstrates three different deficiencies in using Google maps for hiding a cache. Since google maps isn't universally consistent, I can understand why GS still requires "the use of a GPS" for hiding a cache.

 

 

[+Harry Dolphin]

And, sometimes when cachers use Google Maps instead of a GPSr, you get things like this:

Nearest road

Only 408 feet off. Cacher used the 'nearest road' point. And didn't bother updating the coords. Same problem with another cache. For that one, the coords are only 150' off! And no correction made.

Edited December 30, 2013 by Harry Dolphin

[+Hayche]

I would never have thought of being able to get coordinate info from google maps. Thats very interesting, my copy of the os memory maps is quite a few years old and being show its age as there is quite alot of new development around here. I know that yhe satellite images of this area are spot on and quite recent.

 

I am really happy to hear that returning to a new hide several times is basically the way to do it. I did wonder if I was being a bit paranoid.

[+Hayche]

And, sometimes when cachers use Google Maps instead of a GPSr, you get things like this:

Nearest road

Only 408 feet off. Cacher used the 'nearest road' point. And didn't bother updating the coords. Same problem with another cache. For that one, the coords are only 150' off! And no correction made.

 

Definitely not mine. Lol very glad about that too. They have put updated coordinates in the description. Not very useful.

[+Chief301]

I would never have thought of being able to get coordinate info from google maps. Thats very interesting, my copy of the os memory maps is quite a few years old and being show its age as there is quite alot of new development around here. I know that yhe satellite images of this area are spot on and quite recent.

 

I am really happy to hear that returning to a new hide several times is basically the way to do it. I did wonder if I was being a bit paranoid.

 

Google Maps is handy to double check your coordinates to see if you're REALLY off the mark. But don't rely on them completely...in some areas they may not be aligned perfectly with reality, as dprovan said. If you've done your homework and took care getting your readings right, and double checked them in the field, then you find that the Google map imagery is slightly off of that, trust your own readings first.

 

I've heard of newer cachers who go out and get GPS readings, then when they check them against Google Maps and find a discrepancy they change their coordinates to whatever Google says. So why did you bother going out to get readings?

[tttedzeins]

I usually take numerous readings over a few days and then average them by hand. I then use those coords to try and find the place where I want to hide the cache.