Posting 3 different series of distances for LTT 12018 only bumped it to cr: 2 , so looks like need more commanders submitting for each new system to bump past 2?
I thought about system coordinates a lot in the past days, as I don't really like the way they are "calculated" right now. There is a solution to really calculate the coordinates of an unknown system, when you have 4 distances to 4 known systems.
Good news: after a few days thinking, trying and with some help of a friend I got the solution. Well, my own walks in the maths are several decades in the past...Testing with random known coordinates from EDSC shown errors of 10^-8 to 10^-9 when calculating.
Bad news: after rounding the distances from EDSC to 2 decimal values, like given in the ingame GM, most of the coordinates look good, but there are errors up to 2, maybe 3 units of 1/32 Ly. This is too much.
Right now I'm fiddling around with 5 known reference systems, maybe 6. I hope this gives more precise results.
Edit: With 5 or 6 reference systems it gets more precise, but still some remarkable errors in it.
I tried to take a look at the angles between the reference systems from the view of the unknown system. The error gets smaller when the angles are between 30 & 150 deg, but still hard to predict if the calculation is precise enough.
I thought about system coordinates a lot in the past days, as I don't really like the way they are "calculated" right now.
There is a solution to really calculate the coordinates of an unknown system, when you have 4 distances to 4 known systems.
Good news: after a few days thinking, trying and with some help of a friend I got the solution. Well, my own walks in the maths are several decades in the past...Testing with random known coordinates from EDSC shown errors of 10^-8 to 10^-9 when calculating.
Bad news: after rounding the distances from EDSC to 2 decimal values, like given in the ingame GM, most of the coordinates look good, but there are errors up to 2, maybe 3 units of 1/32 Ly. This is too much.
Right now I'm fiddling around with 5 known reference systems, maybe 6. I hope this gives more precise results.
Edit: With 5 or 6 reference systems it gets more precise, but still some remarkable errors in it.
I tried to take a look at the angles between the reference systems from the view of the unknown system. The error gets smaller when the angles are between 30 & 150 deg, but still hard to predict if the calculation is precise enough.
Does anyone know what happened to TornSoul? I checked his profile and he doesn't seem to be online (as in posted in the forums) for a few weeks. Last thing I heart was that he seemed to be really burned out. If that is the case and given the fact he is the maintainer of TGC I'm wondering how this will effect TGC?
I thought about system coordinates a lot in the past days, as I don't really like the way they are "calculated" right now. There is a solution to really calculate the coordinates of an unknown system, when you have 4 distances to 4 known systems.
Good news: after a few days thinking, trying and with some help of a friend I got the solution. Well, my own walks in the maths are several decades in the past...Testing with random known coordinates from EDSC shown errors of 10^-8 to 10^-9 when calculating.
Bad news: after rounding the distances from EDSC to 2 decimal values, like given in the ingame GM, most of the coordinates look good, but there are errors up to 2, maybe 3 units of 1/32 Ly. This is too much.
Right now I'm fiddling around with 5 known reference systems, maybe 6. I hope this gives more precise results.
Edit: With 5 or 6 reference systems it gets more precise, but still some remarkable errors in it.
I tried to take a look at the angles between the reference systems from the view of the unknown system. The error gets smaller when the angles are between 30 & 150 deg, but still hard to predict if the calculation is precise enough.
Short answer, because I'm on my way back from holidays.
I have in mind that EDSC uses a quadratical approximation to find the coordinates. This involves some (small) errors caused by the system, and it's quite CPU-intense, as far as I read. Besides that it is in Python, and I like PHP
The preferred way is to have an algorithm which calculates the location based on some distances,and no estimation in here.
I know the values are rounded to 2 decimal points, and there are CMDRs mistyping distance values by mistake, and sure there are trolls giving false distances by purpose.
I don't know which methods are used by others, except EDSC. And maybe my information about the EDSC way is outdated, so pls let me know, also about other methods already used by others. Maybe I overlooked something here.
Anyway yesterday I implemented backwards checking of the coordinates found, did about 100-200 manual tests with EDSC coordinates, using 4-6 reference systems. And it showed either false coordinates which were easily detected, or the right coordinates. No false positive.
In the next days I'll make it work with any number of distances >= 4 and make some 10.000 tests with random EDSC coordinates.
I have in mind that EDSC uses a quadratical approximation to find the coordinates. This involves some (small) errors caused by the system, and it's quite CPU-intense, as far as I read. Besides that it is in Python, and I like PHP![]()
Yes, you can get back, because the coordinates are on a fixed grid, provided enough rounded distances. Because our database uses the same grid (and EDSC et al do) no further consequences.The system distances are rounded values from the original galaxy layout. You can't ever get back from the distances to the original coordinates. What consequences has this for our custom database?
If you say we have an effective way to calculate new coordinates, I'll stop (or pause) my effort in this. Still waiting for Tornsoul, hope he turns back in.EDSC/TGC is using trilateration with local grid testing as JesusFreke described. His code is C# I believe, and not publicly available. I use a very similar algorithm in my Javascript version which is available here: https://github.com/SteveHodge/ed-systems
The CPU requirements stem from testing the grid locations around possible candidates generated by trilateration. This is necessary because of the imprecise input data, to maximise the chance of getting an accurate location from poorly chosen references, and out of a desire to have confidence in the outcome. Try testing your algorithm with Sagittarius A* or Alpha Cygni to see why this approach is helpful.
If you say we have an effective way to calculate new coordinates, I'll stop (or pause) my effort in this. Still waiting for Tornsoul, hope he turns back in.
If I want to test these systems I'd need some more distances, but I don't think my algorithm will be better or worse than EDSC's, so no need here. Do you know a way to get the stored distances f.ex. to Alpha Cygni out of EDSC?
If you say we have an effective way to calculate new coordinates, I'll stop (or pause) my effort in this. Still waiting for Tornsoul, hope he turns back in.
If I want to test these systems I'd need some more distances, but I don't think my algorithm will be better or worse than EDSC's, so no need here. Do you know a way to get the stored distances f.ex. to Alpha Cygni out of EDSC?
Cool, I didn't knew this one, only the getSystems. Quick check: With only 6 reference systems my code doesn't find any solution for Alpha Cygni. In the next week or two I'll probably make my code use n reference systems instead of 6, then I'll try this. But no hurry, as yousay the existing way is comfortable.You can use TGC's GetDistances API[...]
Cool, I didn't knew this one, only the getSystems. Quick check: With only 6 reference systems my code doesn't find any solution for Alpha Cygni. In the next week or two I'll probably make my code use n reference systems instead of 6, then I'll try this. But no hurry, as yousay the existing way is comfortable.
...
In case Turnsoul does not come back, does anyone know how to get all data from his API, to have a backup in hand? Has he described this API anywhere?
In case Turnsoul does not come back, does anyone know how to get all data from his API, to have a backup in hand? Has he described this API anywhere?
*redface* I had this in a browser tab, read the GetSystem docu but didn't see the rest. Maybe I have to clean my glassesApi docs are at http://www.edstarcoordinator.com/api.html