foxhunter219 Posted March 28, 2003 Share Posted March 28, 2003 I have seen several references to averaging coordinates. Is this somethiong more than manual averaging by approaching from several directions? If so, is it dependent on particular GPS unit? I have an etrex venture, but I don't find any reference to averaging in manual. Quote Link to comment
+briansnat Posted March 28, 2003 Share Posted March 28, 2003 Magellan units have an averaging feature. Garmin doesn't, so any averaging with a Garmin has to be done manually. The value of waypoint averaging is debatable however. "An appeaser is one who keeps feeding a crocodile-hoping it will eat him last" -Winston Churchill Quote Link to comment
+Markwell Posted March 28, 2003 Share Posted March 28, 2003 Upper end Garmin units DO automatically average. But averaging (both automatic and manually) is overrated. I wouldn't worry too much about it. Markwell Chicago Geocaching Quote Link to comment
+Poindexter Posted March 28, 2003 Share Posted March 28, 2003 My Garmin MAP76S does averaging as do some other Garmin units. Averaging can significantly reduce position error depending on how long you do it. 20 to 30 minutes to reduce error 50% Quote Link to comment
Kerry. Posted March 28, 2003 Share Posted March 28, 2003 quote:Originally posted by BrianSnat:.... Garmin doesn't, so any averaging with a Garmin has to be done manually. The value of waypoint averaging is debatable however. Unfortuneately they do have some auto averaging (recent) software versions. Still waiting for an answer WHY! But yes waypoint averaging, now that's very debatable Cheers, Kerry. I never get lost everybody keeps telling me where to go Quote Link to comment
+RichardMoore Posted March 28, 2003 Share Posted March 28, 2003 The downside to automatic averaging is that it is slower than I walk. Until I found this out I kept walking past the cache. If you have a unit with automatic averaging, stop a few times as you get closer to let it catch up with you. RichardMoore When in danger, or in doubt, Run in circles, scream and shout. Robert Heinlein Quote Link to comment
+Night Stalker Posted March 28, 2003 Share Posted March 28, 2003 I use the automatic averaging when I set a cache. You have to make sure that you put down the GPS and do not stand to cloase as this can effect satellite coverage. When I am caching I have learned to circle the cache and slowly make my circles smaller. This seems to work very well with my SporTrak Pro. Quote Link to comment
+Searching_ut Posted March 28, 2003 Share Posted March 28, 2003 Averaging a position can help, but if done for short periods of time, such as just an hour or so, it can sometimes result in larger errors than what you would have got without it. You also can't say whether an averaged position will for sure be more accurate than any individual waypoint you save. If you run a google search of the sci.geo.nav newsgroup, you'll find lots of discussions on averaging since the removal of SA, and of how long you need to average to be worthwhile. Most of the more modern GPS units by Garmin or Magellan average position, some even if you don't want them to. With the ones that don't average, such as the eTrex, there are several ways in which you can manually average a position with them. An easy way to do it instantly, is with a pocket PC. To post process the data, you can set the track recording function on many of the eTrex models to save trackpoints at set intervals as low as 1 second. It's then quite easy to average this data out, or perform other correction functions on it back on your PC. Quote Link to comment
+shawhh Posted March 28, 2003 Share Posted March 28, 2003 my garmin gps12xl has automatic position averaging. guess briansnat has been misled. -harry Quote Link to comment
+Poindexter Posted March 28, 2003 Share Posted March 28, 2003 As you can see from this excellent page on the subject, the greatest increase in accuracy occurs within the first few minutes of averaging. Quote Link to comment
+Renegade Knight Posted March 28, 2003 Share Posted March 28, 2003 My GPS V averages. But only when I tell it too. Magellans tend to start averaging when you stop moving. Some of the lower end eTrex's don't average. Wherever you go there you are. Quote Link to comment
+briansnat Posted March 29, 2003 Share Posted March 29, 2003 Sorry, I should have been more specific and said Garmin's popular ETrex line doesn't waypoint average. But I stand by my point that the value of the feature is questionable. "An appeaser is one who keeps feeding a crocodile-hoping it will eat him last" -Winston Churchill [This message was edited by BrianSnat on March 29, 2003 at 03:25 AM.] Quote Link to comment
gm100guy Posted March 29, 2003 Share Posted March 29, 2003 I have a Lowrance gm100 and allows averaging. When I place a cache I set it down and let it take a postion for about a minute or so and then save the waypoint. Works for me..... gm100guy http://members.rogers.com/gm100guy/cachepage.htm Ontario geocachers http://groups.msn.com/GeocachinginOntario/homepage Quote Link to comment
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