Am I ever "0 ft" away with a Magellan?

September 10, 2003

I have a MAP330 running v4 firmware. As I try to approach a point, the best I have ever seen the unit's distance indicator is "1 ft". Do the Magellan's ever get to "0". Granted, I realize that EPE was like 20 ft at the time -- so it isn't like it matters that much as far as precision goes -- it is more out of curiosity for me. Is "1 ft" distance the best that the Magellan firmware ever shows? Or do people get "0"?

I also see people sometimes talking about being "0.0". Does the Magellan firmware have a setting that shows tenths?

- John...

September 10, 2003

Don't have the 330, but have a MeriGreen and yeah, I've had it at 0 feet.

Team Kender - "The Sun is coming up!" "No, the horizon is going down."

9.5k · September 10, 2003

Yup. I have had it down to 0 as well. Of course, as speculated, EPE was at 10' but I still didn't find the cache.

Cheers!

TL

3.5k · September 10, 2003

Yup, with my garmin map76, standing on a benchmark, WAAS on, 0' off and on.

"See the wonderous works of Providence! The uncertainty of human things!" Geo.Washington

September 10, 2003

I have a Sportrak Pro. On thhe first cache I did with it, it zeroed out, I looked down, and I was standing 5 inches from the cache. It kind of took the fun out of it. My previous GPS was a 310. It would zero out at .01 miles--or 52 feet away. That GPS sharpened by cache finding skills.

September 10, 2003

I have a Sportrak Map and I have zeroed out a few times.

__________

Gorak

September 10, 2003

quote:
Originally posted by John & Bretta:
I have a MAP330 running v4 firmware. As I try to approach a point, the best I have ever seen the unit's distance indicator is "1 ft". Do the Magellan's ever get to "0". Granted, I realize that EPE was like 20 ft at the time -- so it isn't like it matters that much as far as precision goes -- it is more out of curiosity for me. Is "1 ft" distance the best that the Magellan firmware ever shows? Or do people get "0"?

I also see people sometimes talking about being "0.0". Does the Magellan firmware have a setting that shows tenths?

- John...

Arrrg, where is this "version 4"? All I see is version 2.08!http://www.magellangps.com/en/support/products/upgrades/upgrade_map330.asp

September 10, 2003

Ok -- so it can zero-out. Good to know. Thanks.

As for my second question: Is there some screen that I'm missing with a tenths or hundredths place? All I see for distance is always just a whole number. Just curious if I'm missing some setting.

Again, I realize that when we're talking less than a foot, it doesn't really matter since the EPE is well above that anyway -- but I'm still curious.

- John...

September 10, 2003

quote:
Originally posted by SamLowrey:
Arrrg, where is this "version 4"? All I see is version 2.08!http://www.magellangps.com/en/support/products/upgrades/upgrade_map330.asp

I knew it was just a matter of time before someone mentioned that...

Unfortunately, it is a long, ongoing thing with Magellan. They don't have their latest software out there for public download. And, if someone else puts them up, they send them notices to remove them immediately.

So, there are three ways to try to get the latest version (currently v4.00, I believe):

1. The shady way: Find it on the Net. I don't have anywhere to direct you to, sorry. I didn't get it this way.

2. The truthful way: Call Magellan and ask them for it. Tell them that you want the latest version of their software. Beg them to send you a CD. They likely won't.

2. The white-lie way: Contact Magellan and tell them that you bought MapSend Topo on EBay, but that it didn't come with the driver update disc and are getting an error about the version of your firmware when you try to use it. Recent MapSend Topo versions require that the device have v4.x of the software. They'll send you a disc with the update firmware on it.

Hopefully, Magellan will soon decide that sending out discs is a lame way to do it -- and just provide the latest update on their website.

- John...

September 10, 2003

quote:
Originally posted by John & Bretta:

Thanks for the info, but I have to ask, is there any significant improvement?

3k · September 10, 2003

I've had my Garmin Legend at 0 only a few times. In a perfect world on a perfect day with perfect sky, you might achieve 0ft - approaching destination. But then what fun would this game be? Elevation with a GPS is also not perfect. I had my GPS 6 feet off on a measured elevation spot

Cache you later,

Planet

So many caches, so little time.

September 10, 2003

quote:
Originally posted by John & Bretta:
2. The white-lie way: Contact Magellan and tell them that you bought MapSend Topo on EBay, but that it didn't come with the driver update disc and are getting an error about the version of your firmware when you try to use it. Recent MapSend Topo versions require that the device have v4.x of the software. They'll send you a disc with the update firmware on it.

OOPS! I meant MapSend WorldWide Basemap! Not TOPO! The WorldWide Basemap software is what requires the v4.x firmware -- NOT the TOPO software. So, if someone goes the white-lie route, be sure that you say you have the MapSend WorldWide Basemap application that wants v4 of the firmware -- not Topo (which works fine with previous firmware).

- John...

September 10, 2003

quote:
Originally posted by SamLowrey:
Thanks for the info, but I have to ask, is there any significant improvement?

Well, this is from the README. I think these are the main improvements in v4.x over the current v2.0x...

---

Software Enhancements and Fixes in Version 4.00:

1. The unit now supports the MapSend World Wide.

2. The unit now supports the MapSend Blue Nav.

3. Added features to show object description on map or database.

4. Added a feature for the database listing so that it will change the 1st char to the next or previous alphabet if the ZOOMIN or ZOOMOUT key is pressed.

5. Added "Advanced" NAV Units selection.

6. Added a "Map Utility" in the menu to allow the user to delete a second downloaded base map, detail map and change the base map between the default one and downloaded one.

7. Added a feature to draw a second line from current position to destination after an "GOTO" or "route" is activated.

8. Added maximum speed and average speed to navigation data customization options.

9. Added ability to search nearest to any object.

10. Fixed problems with waypoint projection with primary datum not set to WGS84

11. Fixed track history collection bug.

12. Fix problem with waypoints projection when distances less than 0.10 miles/nm/km.

13. Added warning messages when trying to save current position to a waypoint before first fix or the fix is 2D in auto mode.

14. Some improvements were made to map drawing.

15. Added "EPE" as NAV field choice.

16. Changed the compass design in Compass Screen.

17. Added Day Light Saving in the "SETUP" menu.

18. Added three NAV screens: DATA Screen, SPEED Screen and Road Screen.

---

Hope that helps you. That's about all I know on it.

- John...

September 10, 2003

quote:
Originally posted by John & Bretta:

quote:
Originally posted by SamLowrey:
Thanks for the info, but I have to ask, is there any significant improvement?

Well, this is from the README. I think these are the main improvements in v4.x over the current v2.0x...

Thanks, I did I search on the web and found some info. Thanks for the tip.

4.5k · September 10, 2003

No GPS can actually tell you when you're at 0. If it could, there would be no need of EPE. It could read 0 and you can be 20 feet aaway or it can read 20 and you can be actually 0 feet. The GPS's EPE is just guessing the likelihod of how far you might be away based on signal strength and the numbers of sats its receiving.

The only way to verify how close you actually are is at a known and verified waypoint like a USGS benchmark.

Alan

September 11, 2003

quote:
Originally posted by Alan2:
No GPS can actually tell you when you're at 0. If it could, there would be no need of EPE. It could read 0 and you can be 20 feet aaway or it can read 20 and you can be actually 0 feet.

Correct. I think I was very clear and have stated more than once in this thread that I fully realize that 0 is not really 0 because of EPE. Of course. I just wanted to know if getting to "0" (or "0.0") was even possible on the Magellans, since I had never seen it. I've seen "1 ft" -- and fully realize that is up to "21 ft" if my EPE is 20 ft.

I thought I had made that clear -- sorry if you were confused.

quote:
The only way to verify how close you actually are is at a known and verified waypoint like a USGS benchmark.

Correct. My question wasn't really about trying to verify how close I was at all. Thanks.

- John...

4.5k · September 11, 2003

John: I guess I was posting my point in a general way. You realize what EPE means, but a lot of people don't realize this concept and think the GPS really knows if it's at 0 feet from the "go to" waypoint.

Alan

1.1k · September 11, 2003

0 feet well at least this wasn't a serious question, perfect day or not.

Cheers, Kerry.

I never get lost everybody keeps telling me where to go

September 12, 2003

quote:
Originally posted by Kerry:
0 feet well at least this wasn't a serious question, perfect day or not.

Actually, it was a serious question. I simply asked if my Magellan would ever READ 0 feet. I never asked if I could ever know that I was 0 feet from a target. I fully know that I won't be -- and I fully understand EPE. It was more of a firmware question: whether or not the Magellan MAP330 with v4 of the software ever actually SAYS "0 ft".

That's why I specifically listed the firmware version and GPS -- since I thought it might make a difference.

So, it certainly was a serious question. Thanks.

- John...

September 12, 2003

Even though 4.0 was never posted on the US site, it IS on the Aussie site. Here ya go

http://www.magellan.com.au/downloads.htm##firmware

1.1k · September 12, 2003

John, I did realize what you meant from a firmware point of view and would query that a 0 feet display is actually appropraite. In reality a GPS can't (shouldn't) display 0 feet (regardless of ones location to the mark etc) as 0 indicates a perfect result and that's simply not possible.

Cheers, Kerry.

I never get lost everybody keeps telling me where to go

September 12, 2003

quote:
Originally posted by Kerry:
In reality a GPS can't (shouldn't) display 0 feet (regardless of ones location to the mark etc) as 0 indicates a perfect result and that's simply not possible.

Hmmm... I guess I'd have to disagree with that then. That's why we have EPE. If my EPE is 10' and my distance is "1 ft", then I can approximate that I am within "about 11 ft" of the proper mark. If my distance is "0 ft", then I can approximate that I am within "about 10 ft" of the proper mark.

So, I don't think it is wrong (or impossible) to display "0 ft" -- it's still accurate, once you figure for the EPE.

0 does indicate a "perfect result" if your EPE is 10, of course. So, it isn't unreasonable, I would think, for a valid "0 ft" reading -- provided that you remember the EPE, of course...

In any case, my main question has been answered. I'm still curious if Magellan units can be set to tenths or not though (i.e. 0.5, 0.2, 0.0 readings). Again, mainly just curious because I hear people saying "0.0" -- and I never see tenths. No biggie as far as accuracy goes though, of course.

- John...

September 12, 2003

I have a Mag SporTrak Pro and I've never seen it zero out. Best I've seen is 1 ft.

September 12, 2003

If EPE affects the distance ot a waypoint, does it affect speed and altitude too???

Maps?!? I don't need no stinking maps! I got coordinates!

There's a fine line between Geocaching and mental illness, Im just not sure which side of the line I'm on!

1.1k · September 13, 2003

John, so what your saying is that EPE and distance to waypoint have some connection?

Actually I'm not all that sure why we have EPE (in any practical sense) as on just about every software version (even for different units) it can be different.

It's interesting that you look at EPE and DTG as having some connection?

Cheers, Kerry.

I never get lost everybody keeps telling me where to go

September 13, 2003

quote:
Originally posted by Kerry:
John, so what your saying is that EPE and distance to waypoint have some connection?

Yes! Absolutely!

quote:
Actually I'm not all that sure why we have EPE (in any practical sense) as on just about every software version (even for different units) it can be different.

I'm not sure what you mean. EPE varies constantly as the number of satellites -- and quality of signal from them -- varies.

Unless you mean the fact that the various companies seem to use different ways to compute it -- and therefore it isn't the same across companies or, possibly, even firmware revisions. For example, 10 ft EPE on a Garmin isn't the same thing as 10 ft EPE on a Magellan -- simply because they appear to use different methods to compute it.

quote:
It's interesting that you look at EPE and DTG as having some connection?

Your EPE and distance to waypoint are certainly directly connected.

EPE is the "Estimate of Position Error". It gives an idea of how accurate the current lat/log reading of your GPS really is. So, if your GPS says you are at a specific point on the earth -- then your EPE tells you how much faith or reliance you can put into that reading.

Therefore, when you are measuring distance from a waypoint that you are trying to get to -- you definitely have to consider the current EPE to see how accurate that reading is.

If your GPS says that you are 10 feet from a point -- then have to add (at least) your current EPE to get an idea of just how accurate you really are. If your current EPE was 20 feet -- then you could easily actually be 30 feet (or more -- see below) from the waypoint.

So, yes, you do need to consider EPE when searching for a point. If your GPS says that you are only a few feet away -- but your current EPE is 50 feet due to tree cover -- then you might not even be near it!

Now, on a side note, it should be noted that EPE should NOT even be considered a maximum error reading. If your EPE is 10 feet, that does NOT mean that you are definitely within 10 feet of where your GPS says you are -- it's barely even LIKELY most of the time.

Most "experts" (of which I am not one -- I have no idea how this is determined) say that, for Garmin units, the EPE is a "50% probability" number. That would mean that there is a 50/50 chance that whatever number you see for EPE is really the maximum distance off that you might be. So, to be 95% confident that the current measurement is really within a certain distance, you should probably multiple the EPE value by two.

Many say that the Magellan units would actually need you to multiply by slightly more.

So, in summary, when searching for a waypoint, you definitely need to consider your EPE to see how accurate you are -- and then maybe even double it to go for decent accuracy -- and then you could still be off!

Add in the fact that whoever took the reading to PLACE the cache could have been equally as far off -- and you really need to double it again to consider a search radius!

- John...

Cheers, Kerry.

I never get lost everybody keeps telling me where to go

1.4k · September 13, 2003

I've seen in many side by side comparisons that the Sportrak line takes a step forward from other consumer grade GPSrs in accuracy. WAAS computations seem to be the difference. Especially under moderate tree cover. The tradeoff is that it takes about 1 minute to settle in and get enough WAAS corrections to get a low epe.

1.4k · September 13, 2003

A few notes and tips about my Sportrak. It uses a Helix antennae, this gives you better sat reception only when used properly. When placed touching any large metal item it drastically loses signal, also, placed against your body can detune the receiver to a lesser degree. When you get close (30 ft) to your waypoint, stop for about a minute before continuing. One other thing I've done is to use a pda screen protector (cut to size) on my GPSr to protect the screen from scratches as I'm bushwhacking through the brambles.

9.5k · September 13, 2003

quote:
Originally posted by BadAndy:
A few notes and tips about my Sportrak. It uses a Helix antennae, this gives you better sat reception only when used properly. When placed touching any large metal item it drastically loses signal, also, placed against your body can detune the receiver to a lesser degree. When you get close (30 ft) to your waypoint, stop for about a minute before continuing. One other thing I've done is to use a pda screen protector (cut to size) on my GPSr to protect the screen from scratches as I'm bushwhacking through the brambles.

Ummmm isn't using a GPSr a poor tool for bushwacking?

Cheers!

TL

Am I ever "0 ft" away with a Magellan?

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