X and Y...How about Z?

[BFG99]

This topic occurred to me the other day when I was trying to find a microcache somewhere within a 5-story parking garage.

 

Has there ever been any discussion about optionally recording Z-coordinates (height either in metres or feet above sea level) on Groundspeak? I could see that being useful information in some instances, such as the one I just described. I briefly checked the forum history and didn't see anything about it.

[+narcissa]

Often, with caches like that, figuring out the elevation is a purposeful element of trickery on the owner's part and they wouldn't want to use an optional elevation setting.

[+TerraViators]

It is an interesting element but I don't believe many people would use it. Besides, it could be used as part of a puzzle cache or a CO could simply add that the cache is on the fifth floor, or fifty feet above ground or some such.

[+cerberus1]

I feel "optional" wouldn't get used much.

The few that we've found that were hidden with a difference in elavation were done so on purpose.

 

COs of underground hides probably wouldn't use it.

The one at the top of a 1+ mile waterfall might've, but the CO wanted you to have fun with the journey (another, easier avenue from the top).

For tree, mountain, and water caches, terrain ratings should suffice on most.

[BFG99]

It may not be used much, and I agree it should be left up to the cache owner whether to provide it, but I don't see why it would hurt to have it available as an option if the owner would like to provide it. Maybe only 25% of people would fill it in, and only 10% of cachers would use that information, but why not provide it when the owner wants to?

[+Wet Pancake Touring Club]

Here's an interesting article on barometric altimeters. Most Garmin units have these. http://gpstracklog.com/2012/12/all-about-barometric-altimeters.html

 

In a nutshell, they are not terribly accurate. They do require calibration to be somewhat accurate, and they are affected by local weather conditions.

[BFG99]

Here's an interesting article on barometric altimeters. Most Garmin units have these. http://gpstracklog.com/2012/12/all-about-barometric-altimeters.html

 

In a nutshell, they are not terribly accurate. They do require calibration to be somewhat accurate, and they are affected by local weather conditions.

 

It's interesting that my unit (Garmin ETrex Vista HCx) isn't on the list of handhelds with a barometric altimeter, but it is equipped.

I'd be curious if anyone has done detailed measurements on just how far off a barometric altimeter can be based on air pressure changes via weather. I imagine it could be significant in rugged terrain however. My experience in the relatively flat or rolling terrain I've used mine in is that it's usually within +/- 8 feet from one day to the next, and that's without any calibration.

[+The Leprechauns]

In a nutshell, they are not terribly accurate. They do require calibration to be somewhat accurate, and they are affected by local weather conditions.

This has been my experience as well.

 

Sometimes the cache owner will include altitude as part of the cache description. It can be helpful, for example, when searching for a cache on a steep slope, in order to narrow the search area.

 

I don't think that smartphone apps have a capability to record altitude? So, the info would only be of value to users with a properly equipped GPS, who know how to find and use the altimeter feature. I sure had fun with it when caching last year in Israel (for example, at the Dead Sea).

[+The A-Team]

In a nutshell, they are not terribly accurate.

I can certainly vouch for that. Just a couple of weeks ago, I was walking along a trail just a couple of metres above sea level. My Garmin Oregon 600 was reporting my elevation as -26 metres.

[+noncentric]

It may not be used much, and I agree it should be left up to the cache owner whether to provide it, but I don't see why it would hurt to have it available as an option if the owner would like to provide it. Maybe only 25% of people would fill it in, and only 10% of cachers would use that information, but why not provide it when the owner wants to?

I'm pretty sure that development time is, or should, be directed towards things that affect a wide range of site users. There are plenty of wide-reaching projects that are still on the to-do list, so adding another variable that less than 1/4 of cachers would use doesn't seem like a worthwhile endeavour. IMO, I'd rather the devs spend their time improving bookmark lists and search functionality than adding a field for information that can already be included in the cache description and/or hint.

 

And then there's the accuracy and accessibility issues that others have already mentioned.

[+Harry Dolphin]

But the major problem is that with a GPSr, the accuracy is about 60'.

[+The Jester]

Here's an interesting article on barometric altimeters. Most Garmin units have these. http://gpstracklog.com/2012/12/all-about-barometric-altimeters.html

 

In a nutshell, they are not terribly accurate. They do require calibration to be somewhat accurate, and they are affected by local weather conditions.

 

It's interesting that my unit (Garmin ETrex Vista HCx) isn't on the list of handhelds with a barometric altimeter, but it is equipped.

I'd be curious if anyone has done detailed measurements on just how far off a barometric altimeter can be based on air pressure changes via weather. I imagine it could be significant in rugged terrain however. My experience in the relatively flat or rolling terrain I've used mine in is that it's usually within +/- 8 feet from one day to the next, and that's without any calibration.

The only time I noted a major change/difference, was on a climb in the North Cascades. From the point the rock climb started to the summit was 400 feet. By the time we arrived at the summit (about 1.5 hours) we "were" 700 feet below the starting point. Yep, a front moved in on us.

[+narcissa]

It may not be used much, and I agree it should be left up to the cache owner whether to provide it, but I don't see why it would hurt to have it available as an option if the owner would like to provide it. Maybe only 25% of people would fill it in, and only 10% of cachers would use that information, but why not provide it when the owner wants to?

 

A cache owner can state it if they wish. Should Groundspeak invest time and effort in this change? Just think about everything that would require a change to accommodate this.

Edited May 3, 2016 by narcissa

[+GrateBear]

That's one of the fun things about placing a cache. For some reason, many people always think it's at ground level. Placing them a few feet (or more) up makes it a bit more challenging.

[+Markwell]

About 5.5 years ago, I posted this...

 

Consumer handheld GPSrs calculate elevation very poorly.

I can vouch for that. In some research I did for tech editing a book, I talked to someone on the Garmin technical team.

 

FOR NON-BAROMETRIC ALTIMETERS, because of the angles that the satellites use (based on the distances from the GPS units), they are very narrow angles. These narrow angles give a much wider ranges of proximity to ground. The problem is that if to get a wide enough angle to compute a more accurate altitude, the GPS needs the satellites to be closer to the horizon. If the sats are closer to the horizon, the signal is degraded by the thicker layers of atmosphere - and the accuracy is ruined. So they're in a Catch 22 with accurate altitudes.

 

FOR BAROMETRIC ALTIMETERS ON GPS UNITS, these mirror the altimeters on airplanes. My private pilot buddy showed me how his barometric altimeter was calibrated (a little dial like on the back of a clock) because you needed to listen to the airport status at that time of day to get the barometric pressure offset for the known altitude. The altitude of the runway was a known altitude above sea level, but based on the barometric pressure of the day, you'd have to adjust for the highs and lows (even by the hour).

 

In our area, the topo maps say that everything is around 637 feet above sea level - and we're VERY flat. Adding 6-8 feet to that might indicate that it's up a tree, but then again a mile west of my house is 649 feet elevation. You'd be hard pressed to see the difference.

==================

 

If I've lost you at this point, the consider this: Most GPS units can't get within 30 feet, the altitude could be off by 30 feet, which is pretty significant if you're trying to tell someone it's in the tree top.

Edited May 3, 2016 by Markwell

[+eigengott]

Has there ever been any discussion about optionally recording Z-coordinates (height either in metres or feet above sea level) on Groundspeak? I could see that being useful information in some instances, such as the one I just described.

 

You can record the height as text in the short and/or long description. Problem solved.

 

All GPS receivers I used so far had no code to navigate to a given height (except for an alarm in a Basejump module on one of the Garmins I had). So it's a manual process anyway.