Expected Accuracy?

[+vthadley]

Hi everyone,

 

I'm new to this forum, so hello! I learned about geocaching recently and thought it would make a great family activity (4 finds in, we're all loving it!), so purchased a Magellan eXplorist GC because it had decent reviews as an entry-level GPSr.

 

I'm noticing that my unit can be 30-50 feet off and I'm wondering what the expected range of accuracy is? I think I read somewhere that 30 feet off is to be expected depending on conditions and the number of satellites in range at the time.

 

Does buying a higher end GPSr increase accuracy, or are they all pretty much the same?

 

Thanks so much!

[+KBfamily]

My desire is to be dead on to ground zero so I choose to use my Nuvi 500 road section to get me actually to the cache area and then I use the actual coordinate readings on my Nuvi to find the cache. The arrow on the Nuvi and on my Oregon 400 just don't get me to an acceptable distance from GZ. My nuvi gets me right to where I need to be....I have no desire to only get within 30 feet of a cache....others will disagree with me, but I am thrilled to get RIGHT ON GZ.

Edited July 10, 2011 by KBfamily

[+CacheFreakTim]

30ft off is on par for what most entry level GPSr's will get you. Remember if the person that hid it was up to 30ft off and you are up to 30ft off that is a total of +-60ft!! The biggest mistake many newbies make is thinking they need to be right on top of the cache to start looking. Once you get within 50ft or so put down the GPS and use your eyes. You will find the caches quicker that way.

[+niraD]

Under ideal conditions, a consumer GPSr will be accurate to about 3m (10'). That applies both to your GPSr, and to the GPSr of the cache owner, so you may find the container 15-20' from ground zero under ideal conditions. Under less than ideal conditions, both GPSr readings can be much less accurate.

[+Roman!]

My desire is to be dead on to ground zero so I choose to use my Nuvi 500 road section to get me actually to the cache area and then I use the actual coordinate readings on my Nuvi to find the cache. The arrow on the Nuvi and on my Oregon 400 just don't get me to an acceptable distance from GZ. My nuvi gets me right to where I need to be....I have no desire to only get within 30 feet of a cache....others will disagree with me, but I am thrilled to get RIGHT ON GZ.

 

What if the CO doesn't have a Nuvi like you, how can you be right on GZ if he's off?

[+vthadley]

Ok, sounds like I'm having typical results. Thanks everyone!

[+briansnat]

' timestamp='1310277173' post='4770554']

My desire is to be dead on to ground zero so I choose to use my Nuvi 500 road section to get me actually to the cache area and then I use the actual coordinate readings on my Nuvi to find the cache. The arrow on the Nuvi and on my Oregon 400 just don't get me to an acceptable distance from GZ. My nuvi gets me right to where I need to be....I have no desire to only get within 30 feet of a cache....others will disagree with me, but I am thrilled to get RIGHT ON GZ.

 

What if the CO doesn't have a Nuvi like you, how can you be right on GZ if he's off?

 

I question those who claim that their GPS puts them right on ground zero every time. First off that assumes that the cache's coordinates are always perfectly accurate and that just isn't possible with consumer grade units. Cache coords are bound to be off at least some of the time.

 

I've been dead on the cache with my unit while other cachers were searching 20-30 feet in another direction. Does that mean my unit was more accurate? Not at all. It could possibly mean that the other cacher's units were more accurate and my unit was just as inaccurate as that of the hider's.

[+EdrickV]

That particular GPS is listed as having 3-5 meters accuracy (under ideal conditions) which is about 10-16 feet. Real world accuracy may vary quite a bit though. The Nuvi I originally used for Geocaching (which I think has the same GPS chipset as this unit) could actually tell me what it's current accuracy was. Best I got was like 12 feet, and I think I've seen 30-50 feet when looking for a cache in woods. There was even a case where, in an downtown city environment, the GPS was really no help at all. (The cache description/hint were much more use, so I knew where GZ was. Didn't actually find the cache though.) The tall buildings even messed up non-Geocache navigating a bit at times.

[+popokiiti]

My eXplorist GC has told me I was 1 meter from the cache, and I was. I didn't believe it today when it said 2m, and I should have. It has been off by more - cloudy days, dense tree cover, days with a y in them, phase of the moon - we just get to the general area then look. I wasn't prepared to shell out more money than the GC cost, but did want the paperless function.

Give the GC some time, you will probably want to upgrade eventually, but it's a great starter unit, that's for sure.

[+Borst68]

Accuracy of any GPSr is based on many things. If you are in a dense forest with lots of tree cover, your accuracy will suffer due to the leaves. Visit that same area in the fall when the leaves are down and your accuracy should be much better. If you are at the bottom of a steep, narrow canyon or ravine, the GPS signal can be blocked by the terrain. Less satellites means worse accuracy. Certainly there are other factors (clouds, as mentioned above) that effect accuracy.

[+Trucker Lee]

Next to or between buildings will also affect it. One important thing, verify you are on the correct setting for Groundspeak, WAS84.

 

OOPSY! Thanks EdrickV. WGS84.

Edited July 12, 2011 by Trucker Lee

[+EdrickV]

Next to or between buildings will also affect it. One important thing, verify you are on the correct setting for Groundspeak, WAS84.

 

I think you mean WGS84.

[Emagnis]

Hello.

 

I hope this hasn't been asked and answered, but here goes.

 

I have a Magellan Explorist 100. My question is that when I am going to save coordinates, how close should the accuracy be before I actually click "mark"?

 

I noticed this afternoon when I was playing around that the accuracy varied anywhere from 36' to 108'.

 

In the past I've never paid a lot of attention to it. As long as I had a 3D fix, I'd just click mark. When I've generated maps from the coordinates, they appear to be accurate. If I hide a cache in the future, I want to make sure I'm as accurate as possible for those who might choose to look for it.

 

Thank you in advance for your help!