+Captain Morgan Posted January 30, 2004 Share Posted January 30, 2004 Hi! At least here in Finland mystery caches based on triangular mathematic problems are quite common. Here's two examples: Riihimäki Geochallenge and Jaarikanmaa These can be solved mathematically (like in this thread: Triangulation experiment) , or by some CAD program etc. What I'm looking for is an EASY way to solve this kind of problems. I don't like maths too much, nor I don't have any CAD-programmes. I guess the situation is the same with many geocachers. Is there any free (or cheap commercial) on-line calculators or dowloadable programmes where you could just enter coordinates, distances, angles etc. and then get the final coordinates as a result? Please feel free to Markwell me, I tried to search from these forums, but could not find anything useful. Quote Link to comment
+The Cheeseheads Posted January 30, 2004 Share Posted January 30, 2004 I own one of these, Gee, I'm a Tree! Most people have been able to figure it out on their own, but if they can't I have two things to offer for help: a web page showing how to do the math, and an Excel spreadsheet where you can plug in the numbers as you need them. The math is out there... Google is your friend! Quote Link to comment
+Captain Morgan Posted January 30, 2004 Author Share Posted January 30, 2004 The math is out there... Google is your friend! Yee yee, I know, Google is my old friend but the amount of links it gives with keywords like "online calculator triangular coordinates" or something similar, is huge. Ok, here's one good link, it has helped me with some caches but only with easy ones: Great Circle Calculator by Ed Williams Something like that would be cool to find when Ed does not help... What's the Excel sheet you mentioned? I have one by Jeff Laake, but when we tested it here in Finland it gave always false final coordinates. Cheers, Olli Quote Link to comment
+Renegade Knight Posted January 30, 2004 Share Posted January 30, 2004 Captain, The easiest way is to find one of your local and esteemed cachers who does like these kind of caches. Then offer up some fine spiced rum as your part of the bargain. Then let them get to work, you quench their thirst and together go find it. While it’s as much work as actually solving the puzzle it’s a kind of work that some people are better suited for. Quote Link to comment
The_Brownies Posted January 30, 2004 Share Posted January 30, 2004 Sometimes a picture is worth a 1000K words. This website gives you a good visual representation what you need to do. Centoid of a Triangle Personally, I would let my GPS do the work for me. Just find all 3 waypoints and set them in the gps, i.e. A, B, and C. Then find the mid point of A to B, B to C and C To A and create 3 more wpts E,F & G. (E) 1/2 way between A & B (F) 1/2 way between B & C (G) 1/2 way between C & A You now have 6 waypoints. Set a new waypoint * (H) 1/2 way between C & E. * (I) 1/2 way between A & F * (J) 1/2 way between B & G If you do everthing correctly, the treasure should be in the place that H, I and J are plotted in the GPS. This may look like a bit of work, but you do not have to do any formulas, or convert meters to centimeters, etc. Quote Link to comment
Dinoprophet Posted January 31, 2004 Share Posted January 31, 2004 I solved one of these, the super-easy way: I marked the three points, then I went to my "Nearest Waypoints" page where I could see the distance to each. This will only work if the points are close enough that the distances don't jump to larger units (feet to miles, or meters to km). Quote Link to comment
+The Cheeseheads Posted January 31, 2004 Share Posted January 31, 2004 You could also do it with two friends; go to the vicinty of where you think the cache may be and each of the three people check the distance to one of the three points. Keep moving together as a group until all three have the correct distance to each point. You should now be on top of the cache! Quote Link to comment
+wildearth2001 Posted January 31, 2004 Share Posted January 31, 2004 You could also do it with two friends; go to the vicinty of where you think the cache may be and each of the three people check the distance to one of the three points. Keep moving together as a group until all three have the correct distance to each point. You should now be on top of the cache! Or you could just form the aformetioned groups of friends and start a grid search of about a 5 mile radius of the points. Chances are after a few weeks of carful grid searching with about 20 friends you might get lucky and find the cache (and maybe a few others) Quote Link to comment
+The Cheeseheads Posted January 31, 2004 Share Posted January 31, 2004 You could also do it with two friends; go to the vicinty of where you think the cache may be and each of the three people check the distance to one of the three points. Keep moving together as a group until all three have the correct distance to each point. You should now be on top of the cache! Or you could just form the aformetioned groups of friends and start a grid search of about a 5 mile radius of the points. Chances are after a few weeks of carful grid searching with about 20 friends you might get lucky and find the cache (and maybe a few others) I really wasn't joking. Read some of the logs for my cache and see some of the ways people were finding it. Quote Link to comment
+EScout Posted January 31, 2004 Share Posted January 31, 2004 I did a triangulation cache locally by using Topo! and setting the waypoints and then playing with the distance fom each on the computer. When I got in the field I was very close. My cache Shoreline Triangle is a triangulation that can be done in the field without maps, calculators, compass, mapping GPSr, etc if you know how to use your GPSr.......... Quote Link to comment
+Ish-n-Isha Posted January 31, 2004 Share Posted January 31, 2004 (edited) Visual representations are easiest. A program like Topo USA 4.0 is excellent for this stuff. Mapsource is good too. If you want to go a mathmatical route first you might try here. http://mathworld.wolfram.com/PerpendicularBisector.html An easier formula since it has less steps. But that would be entirely too easy. I just looked a little deeper at your example pages and where you are,..Topo USA wouldnt work for you. Duh! The correct mapsource might if they have one for there. Anyway the idea being to use a mapping program for your area. Another site with some applets is here http://www.saltire.com/gallery.html You can input values and have the applet compute the answers. Edited January 31, 2004 by Ish-n-Isha Quote Link to comment
+cachew nut Posted January 31, 2004 Share Posted January 31, 2004 (edited) I'm pretty sure OziExplorer lets you project a circle from any given coordinate. So theoretically you could project the three circles and get the coordinates of where the three circles intersect. I don't know if that feature is in the trial version or not, but it may be worth downloading. I don't use this program, but have been told it can do this. Edit:typo Edited January 31, 2004 by cachew nut Quote Link to comment
+Captain Morgan Posted February 4, 2004 Author Share Posted February 4, 2004 I'm pretty sure OziExplorer lets you project a circle from any given coordinate. So theoretically you could project the three circles and get the coordinates of where the three circles intersect. I don't know if that feature is in the trial version or not, but it may be worth downloading. I don't use this program, but have been told it can do this. I could not find that feature from OziExplorer (ver. 3.95.2). If any of you also use this programme, could you please check if you can find it. Quote Link to comment
The_Brownies Posted February 4, 2004 Share Posted February 4, 2004 Here's the link .. Click Here !! Quote Link to comment
+wimseyguy Posted February 4, 2004 Share Posted February 4, 2004 I own one of these, Gee, I'm a Tree! Most people have been able to figure it out on their own, but if they can't I have two things to offer for help: a web page showing how to do the math, and an Excel spreadsheet where you can plug in the numbers as you need them. The math is out there... Google is your friend! And located in a very appropriately named facility too: Bong State Quote Link to comment
+bigcall Posted February 4, 2004 Share Posted February 4, 2004 Mapsource (software than came with my Garmin GPSr) will allow you to do this also. You just add a waypoint and edit it such that it draws a circle around it. Unfortunately it's only in miles so some conversion may be in order. The other way I've done these before is to use the math to arrive at the intersection of two circles using UTM coordinates, see: This math link. This will give you (hopefully) two points. From here you can either go to both (not recommended) or just eliminate one based on the third point, or just do another set of math. My alternate route is to create an optimization program that solves a simultaneous equation to a least squares distance. This is truly the geek approach, but it works. Quote Link to comment
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