Cache centroid

[+LewisClan77]

mine is N 38° 47.710 W 119° 09.211 (Centroid is 117 miles from home)

Between Yerington Nevada and Bald Mountain.

 

Closest cache is GC4XKTA

[+uxorious]

So, what is a Cache Centroid, and how do I find it? I assume it is the center of all the caches I've found? If so is there place that tells me this?

 

Seems like everyone but me knows. Or no one else who does not know, cares.

 

Project-gc includes the centroid in your info: http://project-gc.com/ProfileStats/uxorious

 

Yours is alleged to be N47 13.337 W122 11.150

 

I don't get the exact math involved (after trying and failing to reverse-engineer the GSAK macros), but the centroid is an averaging of the latitudes and longitudes of all your finds.

 

Thank you. Very interesting, now to look the spot up on a map.

[+fizzymagic]

I don't get the exact math involved (after trying and failing to reverse-engineer the GSAK macros), but the centroid is an averaging of the latitudes and longitudes of all your finds.

 

Nope.

 

It's the point on the surface of the Earth directly above the centroid of all your finds, which will always be under the surface of the Earth.

 

You calculate it by taking the average Cartesian coordinates of your finds (X, Y, and Z coordinates) and then finding the point on the Earth's surface directly above that point.

 

So if you live on the West Coast of the US and do a bunch of caches in Europe, it will move your centroid north even if the caches in Europe are at lower latitudes. You have to visualize it on the sphere. Likewise, caches in the US will tend to move the centroid northwest for someone in London.

[Glory Hunters]

which will always be under the surface of the Earth.

 

are you sure about that? If it takes into account the Z coordinate, it is possible that the centroid might be above the surface (for example, if you find only caches in the top of mountains :-) )

[+niraD]

I don't get the exact math involved (after trying and failing to reverse-engineer the GSAK macros), but the centroid is an averaging of the latitudes and longitudes of all your finds.

 

Nope.

 

It's the point on the surface of the Earth directly above the centroid of all your finds, which will always be under the surface of the Earth.

 

You calculate it by taking the average Cartesian coordinates of your finds (X, Y, and Z coordinates) and then finding the point on the Earth's surface directly above that point.

 

So if you live on the West Coast of the US and do a bunch of caches in Europe, it will move your centroid north even if the caches in Europe are at lower latitudes. You have to visualize it on the sphere. Likewise, caches in the US will tend to move the centroid northwest for someone in London.

Here's an illustration that may help clarify what's going on.

 

Imagine someone with only two finds: one at longitude W 90° and the other at longitude E 90°, and both exactly 1 mile north of the equator. The centroid will be half-way between the two points, and will be 1 mile north of the center of the earth.

 

Now, if you extend a line from the center of the earth, through the centroid, to the surface of the earth, then this line will go directly north, from the center of the earth to the north pole. Yet the two points are each only 1 mile north of the equator.

[+redsox_mark]

So if you live on the West Coast of the US and do a bunch of caches in Europe, it will move your centroid north even if the caches in Europe are at lower latitudes. You have to visualize it on the sphere. Likewise, caches in the US will tend to move the centroid northwest for someone in London.

 

Yes, that is what it is doing for me. A bunch of caches in the US (which are all south of the UK) has moved it Northwest. That in spite of another large bunch of finds in Australia.

[+fishgeek]

I don't get the exact math involved (after trying and failing to reverse-engineer the GSAK macros), but the centroid is an averaging of the latitudes and longitudes of all your finds.

 

Nope.

 

It's the point on the surface of the Earth directly above the centroid of all your finds, which will always be under the surface of the Earth.

 

You calculate it by taking the average Cartesian coordinates of your finds (X, Y, and Z coordinates) and then finding the point on the Earth's surface directly above that point.

 

So if you live on the West Coast of the US and do a bunch of caches in Europe, it will move your centroid north even if the caches in Europe are at lower latitudes. You have to visualize it on the sphere. Likewise, caches in the US will tend to move the centroid northwest for someone in London.

 

Calculating a Mean Cache Location and comparing it to the Centroid might be an interesting exercise. Also, determining the Standard Deviation would meaningful. My centroid isn't that far from my home location, but a lot more than half of my finds are farther away than my centroid.

[+Gumbys4eva]

Ok, so I don't know how to use GSAK, or anything else for that matter, and have no idea how to figure out a centroid in the first place. Therefore, where do I start with this? There is a challenge cache close to my home.

[+wmpastor]

I don't get the exact math involved (after trying and failing to reverse-engineer the GSAK macros), but the centroid is an averaging of the latitudes and longitudes of all your finds.

 

Nope.

 

It's the point on the surface of the Earth directly above the centroid of all your finds, which will always be under the surface of the Earth.

 

You calculate it by taking the average Cartesian coordinates of your finds (X, Y, and Z coordinates) and then finding the point on the Earth's surface directly above that point.

 

So if you live on the West Coast of the US and do a bunch of caches in Europe, it will move your centroid north even if the caches in Europe are at lower latitudes. You have to visualize it on the sphere. Likewise, caches in the US will tend to move the centroid northwest for someone in London.

Here's an illustration that may help clarify what's going on.

 

Imagine someone with only two finds: one at longitude W 90° and the other at longitude E 90°, and both exactly 1 mile north of the equator. The centroid will be half-way between the two points, and will be 1 mile north of the center of the earth.

 

Now, if you extend a line from the center of the earth, through the centroid, to the surface of the earth, then this line will go directly north, from the center of the earth to the north pole. Yet the two points are each only 1 mile north of the equator.

 

Counterintuitive, & of limited use.

 

Edit/correction: Actually of NO use -- other than wowing acquaintances at caching events!

Edited August 12, 2014 by wmpastor

[+frinklabs]

Ok, so I don't know how to use GSAK, or anything else for that matter, and have no idea how to figure out a centroid in the first place. Therefore, where do I start with this? There is a challenge cache close to my home.

 

http://project-gc.com/Profile/ProfileStats?profile_name=Gumbys4eva&getprofile=Get+profile

 

It says your centroid is at N43° 59.195 W80° 15.095 which is northwest of Orangeville.

 

The nearest cache to that is Kinda' Lonely Road

 

Have fun -- it's a neat challenge!

[+fizzymagic]

I don't get the exact math involved (after trying and failing to reverse-engineer the GSAK macros), but the centroid is an averaging of the latitudes and longitudes of all your finds.

 

Nope.

 

It's the point on the surface of the Earth directly above the centroid of all your finds, which will always be under the surface of the Earth.

 

You calculate it by taking the average Cartesian coordinates of your finds (X, Y, and Z coordinates) and then finding the point on the Earth's surface directly above that point.

 

So if you live on the West Coast of the US and do a bunch of caches in Europe, it will move your centroid north even if the caches in Europe are at lower latitudes. You have to visualize it on the sphere. Likewise, caches in the US will tend to move the centroid northwest for someone in London.

Here's an illustration that may help clarify what's going on.

 

Imagine someone with only two finds: one at longitude W 90° and the other at longitude E 90°, and both exactly 1 mile north of the equator. The centroid will be half-way between the two points, and will be 1 mile north of the center of the earth.

 

Now, if you extend a line from the center of the earth, through the centroid, to the surface of the earth, then this line will go directly north, from the center of the earth to the north pole. Yet the two points are each only 1 mile north of the equator.

 

Counterintuitive, & of limited use.

 

Edit/correction: Actually of NO use -- other than wowing acquaintances at caching events!

 

Since you are such an expert, where would you put this hypothetical person's caching center?

 

...

...

...

 

Yeah, I didn't think so. The problem is that mathematically there is no well-defined surface-distance metric that can be used to find the "center" of caches on a spheroid. The mean of the Cartesian coordinates is well-behaved, albeit somewhat counterintuitive. But "of little use?" Why would you say that?

[+Gumbys4eva]

Ok, so I don't know how to use GSAK, or anything else for that matter, and have no idea how to figure out a centroid in the first place. Therefore, where do I start with this? There is a challenge cache close to my home.

 

http://project-gc.com/Profile/ProfileStats?profile_name=Gumbys4eva&getprofile=Get+profile

 

It says your centroid is at N43° 59.195 W80° 15.095 which is northwest of Orangeville.

 

The nearest cache to that is Kinda' Lonely Road

 

Have fun -- it's a neat challenge!

OMG! How did you do this! Thanks so much. Now I've got to head for Orangeville!

[Andronicus]

Mine Centroid is 532 km from home, to the West. It is in the middle of saskatchewan, more than 9km from the nearest thing (there is litteraly nothing there).

[+DanOCan]

Mine Centroid is 532 km from home, to the West. It is in the middle of saskatchewan, more than 9km from the nearest thing (there is litteraly nothing there).

Did you move? Saskatchewan is east of Calgary.

 

I ran the macro to see how mine moved over time. Since a did a number of finds in Oregon early in my caching career, it was well into Washington state for a brief period, then moved over the AB/BC border. Now it has settled in near Coaldale, AB which is actually my hometown, which is a nice coincidence.

[Andronicus]

Mine Centroid is 532 km from home, to the West. It is in the middle of saskatchewan, more than 9km from the nearest thing (there is litteraly nothing there).

Did you move? Saskatchewan is east of Calgary.

 

I ran the macro to see how mine moved over time. Since a did a number of finds in Oregon early in my caching career, it was well into Washington state for a brief period, then moved over the AB/BC border. Now it has settled in near Coaldale, AB which is actually my hometown, which is a nice coincidence.

Woops... East, yah, east. Lets see, Never Wheat Shredded Eat...