First a math question, then... - page 3.

myrkul

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Quote from: SgtSpike on January 02, 2013, 07:03:54 PM

Quote from: grondilu on January 02, 2013, 06:59:47 PM

Quote from: Phinnaeus Gage on January 01, 2013, 10:50:20 PM

Could the exact GPS coordinates be found if only three other GPS coordinates are supplied along with exact distance from each to the desired location? Or would that give you two possible locations?

I don't know much about GPS but to me it seems quite clear, from a purely geometric point of view, that there are two solutions to this problem. Since you probably try to locate a point on the surface of the earth and not in space, it's likely that only one of the two solutions is acceptable.

Except the other three GPS locations used to find the fourth location are on earth, not in space, and the plane of the triangle between those three points could skew the end result if said plane is not parallel to the earth's surface.

Except the earth's surface is not flat. The actual triangular plane is within the surface of the earth, not parallel to it. GPS coordinates are coordinates on a sphere, and a map is a projection of those points. Unless they are very close together, or very different in elevation, the elevation of the points doesn't really matter, as all the distances are along the ground - around the surface of the sphere - anyway. The elevation of the points will, if it's great enough, cause some inaccuracy in the location, but it will still only resolve to one (possibly inaccurate) point on the surface of the earth.

SgtSpike

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Quote from: grondilu on January 02, 2013, 06:59:47 PM

Quote from: Phinnaeus Gage on January 01, 2013, 10:50:20 PM

Could the exact GPS coordinates be found if only three other GPS coordinates are supplied along with exact distance from each to the desired location? Or would that give you two possible locations?

I don't know much about GPS but to me it seems quite clear, from a purely geometric point of view, that there are two solutions to this problem. Since you probably try to locate a point on the surface of the earth and not in space, it's likely that only one of the two solutions is acceptable.

Except the other three GPS locations used to find the fourth location are on earth, not in space, and the plane of the triangle between those three points could skew the end result if said plane is not parallel to the earth's surface.

grondilu

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Quote from: Phinnaeus Gage on January 01, 2013, 10:50:20 PM

Could the exact GPS coordinates be found if only three other GPS coordinates are supplied along with exact distance from each to the desired location? Or would that give you two possible locations?

I don't know much about GPS but to me it seems quite clear, from a purely geometric point of view, that there are two solutions to this problem. Since you probably try to locate a point on the surface of the earth and not in space, it's likely that only one of the two solutions is acceptable.

SgtSpike

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Wouldn't it have two points, even in the event of them NOT being in a straight line?

A triangle still only makes a flat shape. If you take elevation into account (wherever the point to be identified is on a plane other than the same plane as the triangle), wouldn't there be two possibilities with regards to location?

Taking this into consideration, then, what happens if the triangularly-generated plane isn't level with the ground? You could get two fairly different potential locations.

I couldn't readily dive in to all the maths behind this, and am no expert by any means, so someone tell me if I am wrong. I am just picturing some convoluted shape being derived out of 4 points, and then the same shape mirrored across the plane of the triangle making up its base.

myrkul

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Quote from: Phinnaeus Gage on January 02, 2013, 05:33:00 PM

Quote from: myrkul on January 02, 2013, 10:46:34 AM

Quote from: Phinnaeus Gage on January 02, 2013, 10:32:40 AM

I propose:

Sounds nifty. If you can put together a complete plan, you might want to list it on http://bitcoinstarter.com/

Actually, I have an outfit in mind capable of building the device en masse. Retaining capital may not be that big of a concern. What's paramount is brainstormin' the idea to the nth degree in an open-source manner, whereupon the reward for doing such is that all bitcoiners would be able to purchase the item at a steep discount oppose to the SRP that the general public will have to pay.

Granted, such a thing can be easily developed as an APP for a smart phone at a much cheaper price point, but that would negate the aspect of giving a physical gift, one that as it's look upon would elicit emotions for the gift giver. That would be lost if such an item only consisted of binary code in some hand-held device already loaded with gimmicky apps no longer, or worse, never used.

More to come!

~Bruno K~

Agreed on all points. I even have a snappy name: GeoCash. If you like it and use it, send me a few BTC, and I'll be happy.

Phinnaeus Gage

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Quote from: myrkul on January 02, 2013, 10:46:34 AM

Quote from: Phinnaeus Gage on January 02, 2013, 10:32:40 AM

I propose:

Sounds nifty. If you can put together a complete plan, you might want to list it on http://bitcoinstarter.com/

Actually, I have an outfit in mind capable of building the device en masse. Retaining capital may not be that big of a concern. What's paramount is brainstormin' the idea to the nth degree in an open-source manner, whereupon the reward for doing such is that all bitcoiners would be able to purchase the item at a steep discount oppose to the SRP that the general public will have to pay.

Granted, such a thing can be easily developed as an APP for a smart phone at a much cheaper price point, but that would negate the aspect of giving a physical gift, one that as it's look upon would elicit emotions for the gift giver. That would be lost if such an item only consisted of binary code in some hand-held device already loaded with gimmicky apps no longer, or worse, never used.

More to come!

~Bruno K~

myrkul

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Quote from: Phinnaeus Gage on January 02, 2013, 10:32:40 AM

I propose:

Sounds nifty. If you can put together a complete plan, you might want to list it on http://bitcoinstarter.com/

Phinnaeus Gage

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Quote from: myrkul on January 02, 2013, 12:32:44 AM

Quote from: Phinnaeus Gage on January 02, 2013, 12:09:51 AM

Quote from: myrkul on January 01, 2013, 11:58:32 PM

Quote from: Phinnaeus Gage on January 01, 2013, 11:18:48 PM

You are holding a device that reads out that you are X miles away from a specific location. No GPS coordinates are given, with this fact being true for all as I continue with my example. You move to another location of which you know the direction and distance, then reread the device. It now states that you are Y miles from that same specific location. Either from the new location or the original one, you once again relocate to another point, also knowing how far and what direction you traveled. Looking at the device, you now see that you are Z distance from the specific location desired.

Given that, can you triangular where the desired specific location is by one result, or is there a second result that also must be checked?

Assume the distance is in a straight line as a crow flies.

Thanks to all who've answered so far.

~Bruno K~

Somebody got a GPS-locked Christmas present.

Just make sure all three points are not in a straight line, and even if the desired location is outside of the triangle thus created, it will narrow it down to one position. The larger the distance between your bearing points, the easier it will be to plot your destination correctly on a map.

Is there such a thing as a GPS-locked product? This does have to do with such a device, but now you got me wondering if other GPS-locked items are readily available besides the obscured one I discovered.

You answer explains it clearly and perfectly. Thanks, myrkul.

~Bruno K~

http://arduiniana.org/projects/the-reverse-geo-cache-puzzle/

Edit: Derp, I now see you found the same project I was thinking about.

Yeah, 50 tries is WAY too many. For a real challenge, program it for 4 tries. Be sure to include a note marked "Read me FIRST"

I propose:

A lot smaller device (think the size of Matthew's Ellet or smaller).
Only has a read out display and a single button.
The display only reads out miles or kilometers.
The button can act as a rudimentary function if pressed/held in a certain order.
No instructions (but if a person Googled the name or some writing on the device, they would find a website with details).
Programmable, for it would have a port.
Incorporate Bitcoin into the mix, but not necessary for other folks to enjoy it.
The name of the device must be original, and if Googled now, you would see zero results.

Let the market decide what and how it will be used, oppose to dictating its intent. Raspberry Pi owners are using said device well beyond what its developers envisioned.

myrkul

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Quote from: Phinnaeus Gage on January 02, 2013, 12:09:51 AM

Quote from: myrkul on January 01, 2013, 11:58:32 PM

Quote from: Phinnaeus Gage on January 01, 2013, 11:18:48 PM

You are holding a device that reads out that you are X miles away from a specific location. No GPS coordinates are given, with this fact being true for all as I continue with my example. You move to another location of which you know the direction and distance, then reread the device. It now states that you are Y miles from that same specific location. Either from the new location or the original one, you once again relocate to another point, also knowing how far and what direction you traveled. Looking at the device, you now see that you are Z distance from the specific location desired.

Given that, can you triangular where the desired specific location is by one result, or is there a second result that also must be checked?

Assume the distance is in a straight line as a crow flies.

Thanks to all who've answered so far.

~Bruno K~

Somebody got a GPS-locked Christmas present.

Just make sure all three points are not in a straight line, and even if the desired location is outside of the triangle thus created, it will narrow it down to one position. The larger the distance between your bearing points, the easier it will be to plot your destination correctly on a map.

Is there such a thing as a GPS-locked product? This does have to do with such a device, but now you got me wondering if other GPS-locked items are readily available besides the obscured one I discovered.

You answer explains it clearly and perfectly. Thanks, myrkul.

~Bruno K~

http://arduiniana.org/projects/the-reverse-geo-cache-puzzle/

Edit: Derp, I now see you found the same project I was thinking about.

Yeah, 50 tries is WAY too many. For a real challenge, program it for 4 tries. Be sure to include a note marked "Read me FIRST"

Phinnaeus Gage

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Bitcoin: An Idea Worth Spending

This thread stems from an article I read, then directed me to the following blog, all of which I stumbled upon the other day: http://arduiniana.org/projects/the-reverse-geo-cache-puzzle/ Somebody posted a comment that he saw a flaw in the design/process, but he didn't elaborate out of not wanting to disclose for some reason, yet I kept wondering what the heck it was that he was eluding to. I'm assuming it's this triangulation aspect, thus not needing 50 tries to get the box to open (you'll understand this aspect more if you read the blog).

At any rate, I'm calling it a night, but feel free to discuss this some more.

Tomorrow, all.

~Bruno K~

Phinnaeus Gage

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Quote from: myrkul on January 01, 2013, 11:58:32 PM

Quote from: Phinnaeus Gage on January 01, 2013, 11:18:48 PM

You are holding a device that reads out that you are X miles away from a specific location. No GPS coordinates are given, with this fact being true for all as I continue with my example. You move to another location of which you know the direction and distance, then reread the device. It now states that you are Y miles from that same specific location. Either from the new location or the original one, you once again relocate to another point, also knowing how far and what direction you traveled. Looking at the device, you now see that you are Z distance from the specific location desired.

Given that, can you triangular where the desired specific location is by one result, or is there a second result that also must be checked?

Assume the distance is in a straight line as a crow flies.

Thanks to all who've answered so far.

~Bruno K~

Somebody got a GPS-locked Christmas present.

Just make sure all three points are not in a straight line, and even if the desired location is outside of the triangle thus created, it will narrow it down to one position. The larger the distance between your bearing points, the easier it will be to plot your destination correctly on a map.

Is there such a thing as a GPS-locked product? This does have to do with such a device, but now you got me wondering if other GPS-locked items are readily available besides the obscured one I discovered.

You answer explains it clearly and perfectly. Thanks, myrkul.

~Bruno K~

myrkul

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Activity: 532

Merit: 500

FIAT LIBERTAS RVAT CAELVM

Quote from: Phinnaeus Gage on January 01, 2013, 11:18:48 PM

You are holding a device that reads out that you are X miles away from a specific location. No GPS coordinates are given, with this fact being true for all as I continue with my example. You move to another location of which you know the direction and distance, then reread the device. It now states that you are Y miles from that same specific location. Either from the new location or the original one, you once again relocate to another point, also knowing how far and what direction you traveled. Looking at the device, you now see that you are Z distance from the specific location desired.

Given that, can you triangular where the desired specific location is by one result, or is there a second result that also must be checked?

Assume the distance is in a straight line as a crow flies.

Thanks to all who've answered so far.

~Bruno K~

Somebody got a GPS-locked Christmas present.

Just make sure all three points are not in a straight line, and even if the desired location is outside of the triangle thus created, it will narrow it down to one position. The larger the distance between your bearing points, the easier it will be to plot your destination correctly on a map.

Phinnaeus Gage

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Quote from: Third Way on January 01, 2013, 11:01:19 PM

Are you trying to triangulate a position on a map, or of a person? You want to share coordinates? looking fo rsomething specifically?

I'll get to that shortly, TW.

Phinnaeus Gage

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Quote from: payb.tc on January 01, 2013, 11:00:25 PM

woah, i just learned something...

it results in TWO points IF all 3 known points are in a straight line.

and it follows that an infinite number of known points will not reduce this to 1 known point as long as all the known points are in a straight line.

gotta have some kind of triangle there for triangulation Cheesy

That's what I figured.

Allow me to be a little more specific.

You are holding a device that reads out that you are X miles away from a specific location. No GPS coordinates are given, with this fact being true for all as I continue with my example. You move to another location of which you know the direction and distance, then reread the device. It now states that you are Y miles from that same specific location. Either from the new location or the original one, you once again relocate to another point, also knowing how far and what direction you traveled. Looking at the device, you now see that you are Z distance from the specific location desired.

Given that, can you triangular where the desired specific location is by one result, or is there a second result that also must be checked?

Assume the distance is in a straight line as a crow flies.

Thanks to all who've answered so far.

~Bruno K~

K1773R

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/dev/null

if u have 3 GPS cordinates and u know the distance to each one u can triangulate it, this isnt really hard.
if some GPS atributes (x,y,z) are the same it may happen that there are multiple possible positions.

Third Way

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Are you trying to triangulate a position on a map, or of a person? You want to share coordinates? looking fo rsomething specifically?

payb.tc

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woah, i just learned something...

it results in TWO points IF all 3 known points are in a straight line.

and it follows that an infinite number of known points will not reduce this to 1 known point as long as all the known points are in a straight line.

gotta have some kind of triangle there for triangulation Cheesy

drakahn

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I'm not a math brainiac...

but knowing three points, if you draw a circle around each point that has a radius equal to the distance from said point, the circles should meet at one spot... "the location" ...

but I've been wrong before

payb.tc

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it would only result in 1 location.

draw the 3 known ones on a map, and then draw a circle around each one; the radius being their distance to the 'unknown' point.

where all 3 intersect will be where the buried treasure is.

edit: the above assumes either that the world is flat, or that the distance from a known point to the unknown point does not exceed half the earth's circumference (does not wrap around).

Phinnaeus Gage

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I read something the other day that got me a thinkin', but I need to verify something first by you math brainiacs here. Afterward, I'll share with you what I've found, über-similar to something discussed a few times here on this forum. But first, the question.

Could the exact GPS coordinates be found if only three other GPS coordinates are supplied along with exact distance from each to the desired location? Or would that give you two possible locations?

And if three GPS coordinates would result in two locations, would a minimum of four or more equal only one location?

I look forward to the replies.

~Bruno K~

Topic: First a math question, then... - page 3. (Read 3267 times)