Elevation & Format Conversion

[+Mr Smiles]

I have been contemplating a multi cache placement where elevation reading and Format conversion in the field would be part of the description/directions.

 

Imagine going to a five story parking facility with coords that lead you to the front entrance...and leg #1 container is 3 stories directly up over your head. (Elevation Clue) Finding that container, you now are given coords to leg#2 given in UTM Format.

 

My question is; How many GPSrs would not be able to furnish the important info to the cachers? Can most units convert? Read Elevation?

 

Thanks!

Mr. Smiles

[+cache_us_if_you_can]

My question is; How many GPSrs would not be able to furnish the important info to the cachers? Can most units convert? Read Elevation?

I know that our 2 GPSrs can read the elevation, but I'm not aware of either of them being able to convert units.

[+Prime Suspect]

I have been contemplating a multi cache placement where elevation reading and Format conversion in the field would be part of the description/directions.

 

Imagine going to a five story parking facility with coords that lead you to the front entrance...and leg #1 container is 3 stories directly up over your head. (Elevation Clue) Finding that container, you now are given coords to leg#2 given in UTM Format.

 

My question is; How many GPSrs would not be able to furnish the important info to the cachers? Can most units convert? Read Elevation?

 

Thanks!

Mr. Smiles

Unless a GPS is equipped with an altimeter, the accuracy is going to be very poor. It could easily vary by 100ft or more.

[+cache_us_if_you_can]

I have been contemplating a multi cache placement where elevation reading and Format conversion in the field would be part of the description/directions.

 

Imagine going to a five story parking facility with coords that lead you to the front entrance...and leg #1 container is 3 stories directly up over your head. (Elevation Clue) Finding that container, you now are given coords to leg#2 given in UTM Format.

 

My question is; How many GPSrs would not be able to furnish the important info to the cachers? Can most units convert? Read Elevation?

 

Thanks!

Mr. Smiles

Unless a GPS is equipped with an altimeter, the accuracy is going to be very poor. It could easily vary by 100ft or more.

To clarify my last post: The GPSr will have an altimeter, although some may not display the elevation or the user may not know where to look for the display.

[+briansnat]

Unless the GPS has a barometric altimeter, they aren't accurate enough to rely on. Though my Vista is pretty accurate, it has a real altimeter. My Legend could be off by as much as 200 feet.

 

Aince most GPS's don't have a real altimeter it would rule out most GPS's on the market

Edited September 16, 2004 by briansnat

[+Prime Suspect]

To clarify my last post: The GPSr will have an altimeter, although some may not display the elevation or the user may not know where to look for the display.

Like briansnat said, most consumer GPSRs don't have altimeters. Instead, they attempt to determine elevation from the satellite signals. You'll need a clear view of sky, and the accuracy will be really bad. It could easily be a couple of hundred feet off. For the purpose the OP had in mind, it's not going to work.

 

As for the format conversion, all GPSRs can do that.

Edited September 16, 2004 by Prime Suspect

[+Mr Smiles]

So, what I gather from these posts and other (limited) research, ELEVATION, as a clue to a cache location, would not be helpful to a majority of GPSr owners. (While my Vista would tell me at a glance if the cache were "UNDER the bridge or ON

the bridge" , a cacher without altimeter function would have to try both.)

 

Regarding CONVERSION of waypoint FORMAT, there is still confusion. From what I gather about this, MOST GPS units will do the conversion if the cacher just knew how to toggle the right buttons.

 

Is this right?????

[+CapnJackSparrow]

Imagine going to a five story parking facility

My concern would be getting a signal at all inside a parking facility.

[+tirediron]

I think it's a good idea with a little more thought given to the altitude portion of it. Most GPSrs will convert between various formats, so that shouldn't be a problem. Good luck!

[+Thot]

From what I gather about this, MOST GPS units will do the conversion if the cacher just knew how to toggle the right buttons.

 

Is this right????? 

Yes.

[+NightPilot]

The only time the GPS altitude information is close to being accurate and is reliable is if the receiver is receiving WAAS. That's why WAAS was invented - to give aircraft an altitude reading that is dependable, *not* for horizontal accuracy improvement. Horizontal accuracy is already good enough for instrument approaches in aircraft, but it's not possible to do precision approaches (with altitude or glideslope information) without WAAS. And your chances of receiving WAAS inside or even near a parking garage are between slim and none, and much closer to none.

[+writer]

I've seen at least one multi where one of the stages was a number of stories up. However, there was no height given, and you had to figure out that you needed to be on top of the building. (It didn't hurt that it was the only place that you could get a good lock on the satellites.)

 

If you decide to use an altimeter, remember that they *too* can be off by hundreds of feet. The trick is to have the altimeter property calibrated. If you give an absolute height, then give the base level elevation, or express it as an offset elevation, so that no matter what they start at, they can figure out when they are at the right height. Oh, also, altimeters can typically be off by a number of feet, so keep that in mind if the rise is continuous (like a hillside) and not discrete (like floors of a building).