Your Feedback Requested

[+dak's Emu Mob]

G'day All,

 

The document attached below describes how to record accurate, reliable coordinates with a GPS receiver.

 

When people start geocaching, they are often so taken with the activity that they want to place their own cache as soon as possible. In general, this is a good thing, because it leads to a perpetuation of the sport, and allows people the chance to give something back to the geocaching community.

 

However, sometimes the new geocacher's inexperience results in a cache placement that is some distance away from the advertised coordinates. This not only frustrates the people trying to find the cache, but it also harms the new user's reputation in the sport. Placing a geocache is more involved than hiding a container, and pressing the 'mark' button on the GPS receiver.

 

Having been frustrated by looking for caches whose coordinates are 15-20m out, I decided to write a guide that describes how to record accurate, reliable coordinates.

 

The document outlines several tried and true methods for recording coordinates. The initial intention was to describe a general process for recording coordinates. To this end, I contacted twelve active geocachers from all Australian States, and asked them to write down their preferred method of recording coordinates. My plan was to describe a single process, based on the common components of each method.

 

It turned out that the methods varied so much that there wasn't a single 'approved' method for recording coordinates. So, I decided instead to describe some general principles of GPS operation and the conditions that affect the accuracy of readings, and then reproduce the methods that I received in response to my request, in the language used by each geocacher.

 

I've been working on this document, on and off, for many months. Now I would like to seek feedback from experienced geocachers before finalising the document and making it generally available.

 

Please leave your feedback in a reply to this thread. Feel free to comment (positively or negatively) on the technical aspects, the layout, the organisation of the material, the grammar, the diagrams, or anything that you think could improve the document. If you think something could be left out, or if there is something missing, please let me know. Please try to be constructive, not destructive. The idea here is to provide feedback on how to improve the document to make it useful for the intended audience: geocachers (especially newbies), or anyone who wants to accurately record the position of something.

 

I promise to value all feedback, but I can't guarantee that I'll agree with or implement all feedback that I receive.

 

Cheers,

 

dak

 

Download: Recording Accurate, Reliable Coordinates Using GPS (581kB)

Edited May 17, 2006 by dak's Emu Mob

[+gLOBALfINDER]

Well, I read it all, "cover to cover" and find it pretty useful, both in GPS theory and in cache coordinate - finding. Seems to me that from my limited experience, if the unit will average, as my Garmin will, just letting it "do its thing" is the simplest solution, assuming that one has enough sky visibility to have enough satellites to get a low EPE. The new chipsets are really quite good even through quite a bit of foliage, etc. Failing that, projecting a set of coordinates is pretty easy and would be a better solution in a lot of circumstances than repeatedly trying to get a reading in a poor-reception area. Overall, good work!

[RubiconJW]

I also read the complete text, compared the graphics & in general applied the "critical eyeball".

I think you did a wonderful job explaining the third dimention to a GPS fix. Something that's not an easy feat even for those that understand the junction of spherical dimentions...it's one of those concepts thats just hard to put into words...

One of our fine & experienced cachers has a site from which you might garnish a few additional tidbits in conversions & feet per thousandth of degree at specific latitudes etc.. please review :

http://members.aol.com/marklent60544/myhom...rkwellgcfaq.htm

"Markwell" is an outstanding & contributing member of the geocaching family & I'm sure he'll be willing to assist in your endevour.

A section explaining the metric UTM system would be a fine addition as well as including the necessary formulas for converting Meters to Ft, Km to Miles, DDD.MM.SS to DDD.MM.MMM etc.

Given the explainations thus far I'm sure there will be no problem explaining polar convergence of longitudinals and why a degree on the equator is NOT equal in feet / meters to a degree at the 45th parallel.

On the whole... this looks great. I look forward to the final version as a reference to new cachers as well as hunters, hikers & other outdoor enthusiasts.

 

All my best mate..

JW

[+Grusvag337]

This looks like a great document with all kinds of useful and interesting information, however it's unfortunate that the pdf document is password protected and is not allowed to be printed. I'd much rather sit down and read a paper version than scroll through it on the computer.

[+briansnat]

I think its overkill. Some of the background info is great for novices, but 21 pages for what is a very simple procedure?

[+Renegade Knight]

I think its overkill. Some of the background info is great for novices, but 21 pages for what is a very simple procedure?

He covers some of the other navigation questions that come up including the use of a compass.

 

Back to the OP.

 

My method is 8. I don't look at EPE I just hang the GPS From a branch or set it on a rock over the cache and let it average while I finishe hiding the cache. When I'm done, however many points it took is what I average. Sometimes I just take a coordinate.

 

The only time I've ever had a complaint about accuracy was when the cache was by a rock face, under heavy tree cover and all of that was under 230 Kilovolt Amp power lines. All of which mess with your GPSs reception.

 

Something I've noticed. Novice Garmin uses tended to have better coords than novice Magellan users. This was in the sport track day. I think it had to do with the fact that the magellans have some sort of averaging function. The same thing that would cause the boomerange effect. You could not just walk up and take a coordinate with a magellan. Letting it settle in was important. The garmin didn't have that so you could walk up and by the time you got a coordinate it was good.

 

In my opinoin (and I have not researched this) the time most people spend averaging doesn't result in much benefit. The satalite geometry hasn't change, the atmospheric conditions have not changed etc. It would help with the rare (but not unheard of) random GPS blown coordinate that is suddenly a couple of miles over. For averaging to truly do the job you would need many hours. Probably at least overnight.

 

Regardless, I think your paper needs to exist and it will make a good addition to the geocaching community.

[+Team Cotati]

Very thorough. Great job Dude!! Cache on Garth!

[+dak's Emu Mob]

One of our fine & experienced cachers has a site from which you might garnish a few additional tidbits in conversions & feet per thousandth of degree at specific latitudes etc.. please review :

http://members.aol.com/marklent60544/myhom...rkwellgcfaq.htm

"Markwell" is an outstanding & contributing member of the geocaching family & I'm sure he'll be willing to assist in your endevour.

Thanks to everyone for the feedback so far. It's much appreciated. There have been some good suggestions. I'll check out Markwell's web site, to see if the information is appropriate for the objective of the document.

 

I think its overkill. Some of the background info is great for novices, but 21 pages for what is a very simple procedure?

I agree that 21 pages seems a lot, but I couldn't pare it down unless I removed the descriptions of the various methods people use, and I consider them to be an important part of the document. I also agree that it should be a simple procedure, but it often isn't for new cachers. Only yesterday I logged three caches from a newbie who had used AUS66 datum. The coordinates for all three caches were 200m (600 feet) out! Experienced cachers usually record accurate coordinates; they use the principles in the document without thinking about it, because experience in finding caches leads to an intrinsic understanding of how GPS works.

 

This looks like a great document with all kinds of useful and interesting information, however it's unfortunate that the pdf document is password protected and is not allowed to be printed. I'd much rather sit down and read a paper version than scroll through it on the computer.

Yes, sorry 'bout that. I also like to have hardcopy when reviewing documents. However, in this case, I wanted to restrict the distribution of the document until it is in its final form. When I finalise the document that security will be removed.

 

Cheers,

 

dak

[+Rhinopkc]

21 Pages would be a much better read if I was sitting in my recliner. How about turning on the print?

[+Wild Thing 73]

21 Pages would be a much better read if I was sitting in my recliner. How about turning on the print?

"Save as" in my documents and you can print and read as you wish...Worked for me...

Edited May 20, 2006 by Wild Thing 73

[+Rhinopkc]

21 Pages would be a much better read if I was sitting in my recliner. How about turning on the print?

"Save as" in my documents and you can print and read as you wish...Worked for me...

 

Not working like that for me.