Ground Zero question…

[goirish75]

Ok, noobie here, only 11 finds and 1 hide to date. When setting a cache (or hunting for one for that matter), should “ground zero” be set right on top of the cache location? Now I am aware of the differential that GPS’s have, and that each unit may be off by several feet, sometimes more, but some I know are very accurate. The reason I ask is that the hide we placed has been getting found with most people commenting that their GPS took them right to the cache, (as I set the coordinates while standing on the cache). But I have found when I am out searching, others “ground zeros” have not been so kind or dead on. I dont know if its my GPS unit or the hider intentionally set ground zero just a little away from the cache so it makes it more of a search when you get there. So whats the protocal with “ground zero”? Is it generally supposed to be set ON the cache spot or just in the general area? Thanks for helping the new team.

[shrek and fiona]

we try to set the cords right on but there is some out there that set there cors way off for the fun of it and that is not kool

[RSplash40]

You hit it on the head there, not every gps is the same. I can sit there and average my garmin 60 for 300 rounds, but you can walk up and be 30 feet off with yours (garmin 60 or any other).

I can agree with S&F in some cases, but this is not a uncommon thing to have happen with any cache regardless of owner’s intent.

[CodeJunkie]

1st – Coordinates should mark the exact location of the cache. Should is the operative word however.

2nd – Exactly right that “Your mileage may vary”. Many factors may play into the coordinate “exactness” including brand of GPSr, model of GPSr, weather, tree cover, moisture (try caching in a swamp on a rainy or foggy morning), etc.

It’s very hard to say what’s exactly right and I’ve even revisited my own caches and notice that my GPSr varies from time to time by 15-20 feet depending on conditions. I always figure if I’m within 20′ feet I’m “at GZ”. The comment “spot on” may also be a bit misleading. If it’s a cemetery hide with only 1 tree (a cedar) in a 50′ area it’s easy to be spot on. “Spot on” in a thick woods with trees every 8-10′ is a totally different compliment.

[Mathman]

It is also important, (I stress this when teaching others) that you should walk away from GZ after you marked it. Then see if you can walk back to GZ using your GPSr. Sometimes if you aren’t moving the coords aren’t great. If you are able to come back to your mark(GZ) within a reasonable disatnce, then you are set to go.

[BakRdz]

I tend to believe people rarely intentionally set the coordinates off significantly, but I’m sure there are a few. As CJ said, sometime even “spot on” coordinates don’t make an easy find.

If you really want to be kind, take multiple readings on different days and average them. Some GPSr even have waypoint averaging so it does it for you. Simply mark a waypoint, then go back another day and select that same waypoint to average it automatically. Still doesn’t mean you’ll be dead on, but it does help your chances.

[The Pirate Monkies]

IMHO I think that it’s best to try to be as accurate as possible, but as previously posted there many factors that can cause inaccurate co-ords… I sometimes cache with muggle friends and often use this phrase, “When we’re within 15′ feet of of ground zero, it’s time to rely on the ol’ Mk.1 eyeball”…

[sevencards]

We have attempted to take the car gpsr (Nuvi) out in pedestrian mode, and that seems to be the furthest off. Averaging about 15-30 feet off. The further off the street the more inaccurate it seemed to work. We do not use that for marking coordinates because of its inaccuracy. On the other hand it seems as if we can tell when someone else marked a cache using a Colorado which is the Garmin mode GPS we use. Has anyone else done the testing to see how accurate their car (Nuvi) worked in comparison to a “more expensive” hand held like a Colorado?

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