# Spherical Geometry

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I am working on a radar gauge, and I need the spherical geometry to compute:- the distance between my aircraft and another aircraft (both aircraft positions given in latitude/longitude)- the bearing (relative heading) of my aircraft relative to another aircraftThanks for any help !!Eric

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Do you need the full spherical geometry or is a "quasi"-flat geometry sufficient? Since radar distances aren't that great a flat geometry could be precise enough.Arne Bartels

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double pi=3.1415926535897932384626433832795;double LLdistance(double lat1, double lon1, double lat2, double lon2){ double distance; lat1=lat1*(pi/180); lon1=lon1*(pi/180); lat2=lat2*(pi/180); lon2=lon2*(pi/180); distance = acos(sin(lat1)*sin(lat2)+cos(lat1)*cos(lat2)*cos(lon1-lon2))*((180*60)/pi); return distance;};double LLcourse(double lat1, double lon1, double lat2, double lon2){ double course; lat1=lat1*(pi/180); lon1=lon1*(pi/180); lat2=lat2*(pi/180); lon2=lon2*(pi/180); course = fmod(atan2(sin(lon1-lon2)*cos(lat2),cos(lat1)*sin(lat2)-sin(lat1)*cos(lat2)*cos(lon1-lon2)), 2*pi); return course;};Chris Filehttp://www.avsim.com/pss/phoenix.jpg

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Thanks for your help !!Your formulas helped me much. My radar gauge is almost finished, it works pretty fine now.Eric

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A little more patience, I'll release it soon. To make you wait, here are some screenshots. They show the 3 radar modes: global, horizontal and vertical.Eric

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Hey thanks for the shots, they look kinda great! Looking forward to the release... :-hahRegards :-wave from EDDFhttp://flightsimmers.net/airport/etti/signature_pro.jpg

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Chris, Thank you.... Been looking all over for this info.Roman(KGRB)

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Just to let you know tables are much faster (cept I dont know how to use them !) and wondering if fsim uses tables in trig calculations?mr gray

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My radar and HUD gauges have finally been released. I included them on Johan Peeters' F-16 panel.Due to problems with Rick Rossner, AVSIM will never see again a single piece of my work. You can get the panel on the other site. Search the file f16pnlem.zip.Enjoy !!!Eric

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Thanks a lot, gonna try it out nowRegardsEtienneEDDF

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Oh yeah, I really must admit, this is great. You did a good piece of work. It doesn't just work, it also looks good (animations etc.)! :-) How the hell did you get the different mouse hot spots moving around... Incredible.Just keep up the great work, would like to see other gauges of this quality! :-hahRegards :-wave from EDDFhttp://flightsimmers.net/airport/etti/signature_pro.jpgPS. Hmmm since FlightSim.Com is down again (as always... :-erks) and since I don't get any acceptable result out of the AVSIM File Library, I don't have a F-16 a/c yet... Tried the panel only with the Learjet.

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Thanks for your compliments !!You can get the excellent F-16 by G.Chiacchietta on FS Freeware.One link is: FRF_F-16_C.zipHave fun !!

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Hey I just woke up, got to the PC, fired up FS and tried it once more, with 100% ATC, and it's just cool!!! Escorted a Dash 8 in my, errr... still - Learjet. But thank you for the link, I gotta download that F-16 now. But tell me one thing: Well I've seen it on other fighter panels, but what's that indication?http://flightsimmers.net/airport/etti/avsi...hers/escort.jpg> Have fun !!I DO!!!Thanks again! :-hahRegards :-wave from EDDFhttp://flightsimmers.net/airport/etti/signature_pro.jpg

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This indicates if you're flying straight, climbing or descending. It is redudant with the 2 little arrows that appear on the HUD above or below the altitude numerical display.It is a sort of vertical speed display which only indicates if it is positive, negative or null.Eric

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Eric, the RADAR gauge is just BRILLIANT! The HUD is super as well, nice to finally have a decent one I can add to fighters, but the RADAR gauge just totally stole the show. And I love the way the details show up on the HUD too. I am VERY impressed. I loved your AIRBUS gauges and this is just another fine piece of work. Truly excellent.Would it be possible to extend the range of the RADAR to, like, say, 80miles? Or is this something that would involve a lot of re-coding? Or is it even feasible?

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Well, I decided to make this gauge a little more stand-alone, so I could add it to any panel I want. I am using Buddy K. Guy's RKG buttons so I can call it up as a "MINI_CONTROLS_PANEL" window wherever I want... that won't ever conflict with anything. :)This allows me to place a button on the main panel to call the window, and then I have a transparent button on the window bitmap which closes the radar window. (The X on the left bottom button.)I added the mode and zoom buttons to it, so it is basically a "stand-alone" radar unit. I am not at all that happy with the quality of the bitmap I needed to use, so if anybody has a better, similar bitmap which I could work with Photoshop, I'd appreciate it if you could e-mail me a copy. (jspx@mac.com)Eric, you could release this as a stand-alone add-on with the right good looking bitmap. I could package it and write some installation instructions. :)Here is a shot of it installed in my A-10.http://www.lovett.org/jsp/pub/fs/radar.jpg

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Ok thank you for that information.Grrrr my god I'm learning how to make gauges (at least I try...) but it never seems to work. And when it finally compiles without an error, FS crashes... Goddamn...Did you compile using VC++ or BCC55?Regards :-wave from EDDFhttp://flightsimmers.net/airport/etti/signature_pro.jpg

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Tried a less "military" approach, and created something a bit more civilian. Still not 100% happy, but it's better than the previous one, I think.http://www.lovett.org/jsp/pub/fs/radar2.jpg

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I use VC++ 5.0.I'm sorry that it doesn't work for you. C programming is not that easy. I did this for years for my work, so it is relatively easy for me (it is my job...), but I understand that it is complex for someone who discovers it. VB is much easier, but unfortunately you can not develop gauges with VB.Did you try XML gauges?Eric

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Thanks for your compliments !!Today, it is not possible to extend the radar range over 40 NM, because it is based on the information provided by FSUIPC. For performance reason, it is limited to 40 NM, and only Pete Dowson can change this. In my opinion, 40 NM is enough, and it is quite realistic compared to the performance of real aircraft radars.EricVisit my web site

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I like the concept of having the radar in a separate window. It helps in integrating the radar in panels where there is no room to put the radar.I think the window graphics are OK. If you want to release the modified panel, or just the additional panel window, I'd just like to see it before giving you my authorization to release. If you prefer, you can send me what you did (including the documentation) and I'll publish it for you. As you wish...EricVisit my web site

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Yup dude, I tried both XML and C gauges (BCC55 compiling). I think it may get easy if you once get the hang of it. But that might be the most difficult part (at least for a beginner), to get the hang of it...Well the FS crashes, maybe it has to do with Win XP, I know there are some problems which have also been discussed in the Aircraft and Panel Design Forum.But damn it, I won't give up, until I have my (really MY, not a tutrial) first working gauge ready to fly.Hehe it's gonna take some time til I make some of the complexity of yours... :-hah You're doing very well.Keep it up man!Kind Regards :-wavehttp://flightsimmers.net/airport/etti/signature_pro.jpg

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What I think I'm going to do... is write some instructions/tutorial on how to add windows and toggle buttons using one or two of the default aircraft as examples. I'll probably use the King Air, Mooney, and Baron. With that information in hand, the end-user should be able to figure out how to add it to any panel they so wish.I'll keep in touch Eric, and I'll update you as to my progress in writing this thing out. Also, no problem with the RADAR range, I was just curious if it could be extended or not.

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>until I have my (really MY, >not a tutrial) first working gauge ready to fly. Well, I do now! It went faster than I thought!There were as usual some XP problems, frozen progress bars in FS, program crashes, computer reset knob hittings *:-* but the result is there, yeah. :-beerchug:9 Way to go!http://flightsimmers.net/airport/etti/signature_pro.jpg:-newbie

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