Boing!

[+Lostboy1966]

Ah, signal bounce. Did you ever have a spot you wanted to hide in where getting an accurate read seemed impossible? I've just come back from my fourth trip to recheck coordinates for a container I hope to put out soon. The visits have ranged from early morning to late afternoon, and the readings constantly fluctuate by 30 feet (9 meters). I do multiple waypoint averaging checks each visit with my 64sx, and when done I test and my distance goes from single digits to suddenly 25 feet away. The spot is rocky and near a reservoir, a setting I've always found to be problematic. At what point do you just slap another star on the difficulty rating and give a detailed hint?

[+lee737]

Good on you for putting in the effort for great coordinates.... 

I would use a weighted (by eye) average of the coordinates you have, then mention the area is difficult, and flesh out the hint.....

[+niraD]

39 minutes ago, Lostboy1966 said:

Did you ever have a spot you wanted to hide in where getting an accurate read seemed impossible?

I haven't tried to hide caches in locations with bad GPS reception, but I've found a few where the Estimated Position Error (EPE) was over 100ft (30m). In those cases, the CO provided the best coordinates he could, explained the situation so seekers would be aware of it, and provided additional hints to help seekers correctly identify GZ.

 

If there are locations nearby with better reception, then you could use readings from those locations to get more accurate coordinates. For example, you could take the coordinates 100ft in one direction, take coordinates 100ft in the exact opposite direction, and then average the results. Or you could take the coordinates from somewhere due north (or south) of GZ, take the coordinates from somewhere due east (or west) of GZ, and then mix and match the longitude and latitude values to get the coordinates at GZ.

 

[+TeamRabbitRun]

I have a hide on a bridge 212 feet over the Hudson River in New York, and THERE'S some bounce - that flat water plane below in all directions: the river's a half-mile wide!

 

AND, to make it more interesting, the local aerial imagery is oblique - it was shot from way off to the south. The effect is that the cache location is marked as if it were down on the surface, 212 feet below, and because the bridge is so high the cache appears to be sitting in the water!

 

You can see it sitting between the bridge columns where THEY contact the water, but the oblique effect is that the bridge looks like it's leaning away from the camera. in the image I posted below, the bridge tower on the left in actually plumb and underneath the bridge deck.

 

So, between the megabounce and the wonky imagery, you can BET I included a disclaimer about accurate coordinates and how I got them.

 

 

Edited March 5, 2022 by TeamRabbitRun

[+GeoElmo6000]

10 minutes ago, TeamRabbitRun said:

I have a hide on a bridge 212 feet over the Hudson River in New York, and THERE'S some bounce - that flat water plane below in all directions: the river's a half-mile wide!

 

OT but... went to visit Marist for a potential college for one of my kids, and saw this bridge, and... wow!  That bridge is HIGH up there!  I don't like heights and don't think I'd like it.

[+Mudfrog]

It's not mine but there is, at least there used to be,  a cache at street level between some tall buildings in Houston. The gpsr readings were all over the place causing us to have a heck of a time narrowing down that one's hiding spot!

Edited March 5, 2022 by Mudfrog
Added some text.

[+TeamRabbitRun]

1 hour ago, Mudfrog said:

It's not mine but there is, at least there used to be,  a cache at street level between some tall buildings in Houston. The gpsr readings were all over the place causing us to have a heck of a time narrowing down that one's hiding spot!

 

I've cached in midtown Manhattan, in the Concrete Canyons, where even the simplest of trads is tough.

[+TeamRabbitRun]

1 hour ago, GeoElmo6000 said:

 

OT but... went to visit Marist for a potential college for one of my kids, and saw this bridge, and... wow!  That bridge is HIGH up there!  I don't like heights and don't think I'd like it.

 

Come back! It's 20 - 25 feet wide! Stay in the middle and there's NO issue.

My team Cap'n felt the same as you and once I got her out there once she loves being out there.

We even do their night events!

Edited March 5, 2022 by TeamRabbitRun

[+Lostboy1966]

1 hour ago, TeamRabbitRun said:

So, between the megabounce and the wonky imagery, you can BET I included a disclaimer about accurate coordinates and how I got them.

 

So you're saying I should NOT jump off of the bridge?

[+dprovan]

4 hours ago, Lostboy1966 said:

At what point do you just slap another star on the difficulty rating and give a detailed hint?

The point at which I'd give a detailed hint is when it's unfair to expect anyone to find the cache using a GPSr alone. I don't know about the star of difficulty, but the important observation is that no matter how perfect you manage to get your coordinates, seekers are going to run into exactly the same problem, and all the fancy tricks you used to get the precisely correct coordinates aren't going to be available to them. Kudos for doing everything you can to figure out the coordinates, but don't fool yourself into thinking the accuracy of your coordinates is useful to a seeker.

[+Lostboy1966]

18 hours ago, dprovan said:

The point at which I'd give a detailed hint is when it's unfair to expect anyone to find the cache using a GPSr alone

Exactly. I have added this to my notes in the cache page draft (along with a very detailed hint):

The area of the hide has extreme signal bounce, to the point that I added a full star to the Difficulty Rating. Use the Hint with no shame!