known Caucasus Map using real life magnetic heading as true heading in game

[Cookie01]

Hi guys!

This is an issue i've always had a difficulties with, and it always felt off when flying on the caucasus map.
Let's take Kutaisi airport runway 07 for example:

https://imgur.com/KOualyn

https://imgur.com/uDsLhq6

i've put an f-16 on the runway and low and behold it states a true heading of 74° on the DED and a magnetic heading of 67 or 68 in the hud depending on the date

https://imgur.com/71d8yGu
that means that headings in the mission editor and the f10 map are true headings

 

after checking skyvector, which displays magnetic headings it showed that kutaisi had a magnetic heading of 74° and after checking pilotnav, it revealed that the true heading would be 79.8°

https://imgur.com/dtzebJg

https://imgur.com/qDYUTLb

https://skyvector.com/airport/UGKO/Kutaisi-Airport

http://www.pilotnav.com/airport/UGKO

 

after checking jeppesen charts, it says again: runway heading 074° which again.. is magnetic..IRL.. but heading 074° in DCS:Georgia is TRUE
https://imgur.com/a/dYhv7PW
 

i also checked with the other terrains such as NTTR and PG and every heading correspond to the real life headings
i've added the Nellis AFB for completeness' sake:

https://imgur.com/a/AYUX5pN

https://skyvector.com/airport/LSV/Nellis-AFB-Airport

http://www.pilotnav.com/airport/KLSV

 

and here it says explicitly TRUE heading, which corresponds with the True heading in the DED

checking the charts it says 209.2° which is magnetic, which roughly corresponds with our magnetic heading indicated in the viper (the slight variation is date-dependant)

https://imgur.com/a/DreVpuO

so in conclusion we have now learnt that DCS:Georgia uses the real life Magnetic heading as True Heading

if the problem still is unclear please ask, and i shall try to make it more clearer

 

[Ironhand]

The problem is that the Caucasus map world is flat, while the real world is curved. Or is it that the real world is flat and the Caucasus is curved? I get so confused sometimes...

 

Edit: This map is from another time and, really, almost from another sim. In fact, this map is so old that its “0” point is in the southwest corner of the Crimean Peninsula.

Edited April 19, 2021 by Ironhand

[shu77]

The challenge I find with these constantly is that the MAGvar is dependent on the year, which I believe DCS models to an extent.  I find this issue when doing charts a lot, I can put in a MagVar and a heading but given the maps will all be used over a conservative 60 year period.  the reality is that even at .1 degree change per year you will see wild variations depending on the year.  Personally I use 2020 when drawing maps and I have noticed more than a few Syria maps where the runway numbers dont correspond to the true heading on the field.  I think it is mainly a limitation of the scenario that is trying to be modelled more than anything else, but also as Ironhand mentions the flat/round earth thing is also a bit of a nuisance and something I dont think the engine is really built to accomodate. 

 

[randomTOTEN]

There are several problems when I try to study this bug report.

 

1st: The F-16's magnetic compass is oriented to map north. I.E. it does not correctly account for variation at all. I tested this by switching the same unit to the A-10C and seeing a different compass reading at the same takeoff point (Kutaisi Rwy25).

On 4/16/2021 at 10:31 AM, Cookie01 said:

and behold it states a true heading of 74° on the DED

This is not correct. True heading doesn't exist in DCS (the simulation) as a concept.

 

On 4/16/2021 at 10:31 AM, Cookie01 said:

https://imgur.com/KOualyn

https://imgur.com/uDsLhq6

The 074 direction value in both of these screenshots is not correct in reference to True North. DCS Caucasus is a flat earth, not a globe. This is why your direction calculations are off.

 

On 4/16/2021 at 10:31 AM, Cookie01 said:

that means that headings in the mission editor and the f10 map are true headings

No. They are grid headings. (interesting aside, this is properly labeled in A-10C INS).

 

On 4/16/2021 at 10:31 AM, Cookie01 said:

after checking jeppesen charts, it says again: runway heading 074° which again.. is magnetic..IRL.. but heading 074° in DCS:Georgia is TRUE

When you correct for local true north from grid (using i believe what is called the "fork" value)... this appears to be correct.

 

On 4/16/2021 at 10:31 AM, Cookie01 said:

i also checked with the other terrains such as NTTR and PG and every heading correspond to the real life headings

This doesn't sound right. If this is the case then the other airfields are oriented incorrectly. And that's another point of clarification, so far you are only talking about airfield orientations. This doesn't make any conclusions about the orientation of the entire map.

 

On 4/16/2021 at 10:31 AM, Cookie01 said:

[NTTR example] and here it says explicitly TRUE heading, which corresponds with the True heading in the DED

"True" has a difference of 1 degree. Magnetic difference possibly 1.5 degrees. Possibly a fork value of 1. I would need to check a mission on it.

 

A-10C is a better judgment of this, considering the compass error in the viper.

Edited April 20, 2021 by randomTOTEN

[randomTOTEN]

[Cookie01]

53 minutes ago, randomTOTEN said:

On 4/16/2021 at 4:31 PM, Cookie01 said:

and behold it states a true heading of 74° on the DED

This is not correct. True heading doesn't exist in DCS (the simulation) as a concept.

i don't understand.. why is the editor and f10 map then showing true headings ? is it grid heading then? , like you mentioned afterwards ?

 

 

53 minutes ago, randomTOTEN said:

No. They are grid headings. (interesting aside, this is properly labeled in A-10C INS).

ok you are right, they are grid headings, but would the difference between grid heading and true heading and flat + curved make as much difference as 6° ?
this is in my eyes far too convenient to call it a coincidence

considering all you've said, which i believe is correct, let me explain my standpoint:
i want to be able to fly tacan approaches to an airport, using real world jeppesen charts, this works fine with PG,NTTR and Syria, but it does not work with Caucasus because i always end up offset by 6-7° depending on location, which is also the magnetic declination.. 
let's stay with kutaisi 07, so to approach runway 07 i'd set the needle to (according to RL charts) a course of 074°.. i approached and was off by +6°
i tried the same approach again but now with a course of 68° and now it works.. my problem here is that i don't understand where the 68° come from.. my first explanation would be that DCS Georgia uses the RL magnetic heading as Grid Heading (<- see i corrected it   ) and this is actually the only possible explanation that came to mind..

this problem like i said earlier only persists on Georgia, as i can always line up my aircraft with the runway no problem in the other maps, using real life charts..
and yes, the problem may be amplified because of the actual flat modelling but still i don't believe that it's coincidence, given that DCS georgias true heading differs as much as 6 degrees from real life.. 

This doesn't sound right. If this is the case then the other airfields are oriented incorrectly.
Why would they be oriented incorrecty ? charts are made using magnetic headings, and these magnetic headings do correspond by what is represented in the airplane's magnetic heading. ( i wasn't talking about the f-10map/editor)

 

And that's another point of clarification, so far you are only talking about airfield orientations. This doesn't make any conclusions about the orientation of the entire map.

that's the thing.. i am not sure if the airfields are misaligned or the whole map is misaligned.. the only facts i can go off is the runway headings.

all being said, you do understand what i am trying to point out, don't you?

Edited April 20, 2021 by Cookie01

[randomTOTEN]

47 minutes ago, Cookie01 said:

but would the difference between grid heading and true heading and flat + curved make as much difference as 6° ?

it can be as much as 180 degrees

 

47 minutes ago, Cookie01 said:

i want to be able to fly tacan approaches to an airport, using real world jeppesen charts,...but it does not work with Caucasus because i always end up offset by 6-7° depending on location, which is also the magnetic declination.. 

where are you getting RL tacan approaches for the Caucasus? Many of those TACAN stations don't exist in real life, many stations (like the VOR in Sochi) are in different locations in RL vs DCS. My personal policy is to reject RL charts in the caucasus map. Yes, it does work better in Nevada. But we probably ignore or don't notice the minor errors there. You didn't notice the 1 degree error. If you can accept a merely 6 degree error and misplaced navaids you can be pretty happy with the Caucasus too.

In DCS the variation is directly applied to the Grid course. Which results in a strange situation of GC+/-MV="MC" It's a nonsensical solution for anything outside DCS. The equivalent of rotating grid north by a value equal to the variation.

47 minutes ago, Cookie01 said:

let's stay with kutaisi 07, so to approach runway 07 i'd set the needle to (according to RL charts) a course of 074°.. i approached and was off by +6°.. my problem here is that i don't understand where the 68° come from..

let me try and show you:

 

when I measure the direction of the local meridian to Kutaisi (E042°30.0) I get a "DCS Grid Course" of 353° This line defines a True course of 000°T

so we know that at this location the "fork" value is 7 degrees East. The runway measures 073°G, so 73+7=80. The true course for the runway as depicted in DCS is 080°

compare 080 to your statement:

On 4/16/2021 at 10:31 AM, Cookie01 said:

after checking pilotnav, it revealed that the true heading would be 79.8°

 

now we calculate the DCS "Magnetic heading"

we subtract 6E from 073G gives us the "DCS MH" of 067 which you see on the HUD and properly working wet compasses in DCS. The TACAN is oriented this same way, so when you set the inbound course of 074-067=about a 7 degree alignment error.

but for the same pavement in DCS if we subtract 6E from 080T we get 074 which is correct. But the TACAN's reference radial isn't pointing at local magnetic north, but instead pointing at GN+/-MV because that's the direction every compass and flux gate valve in DCS Caucasus is pointing on a flat earth.

 

47 minutes ago, Cookie01 said:

all being said, you do understand what i am trying to point out, don't you?

Yes,

the best solution I have is to either accept the 5-6 degrees of course error, or reject using real charts

Edited April 20, 2021 by randomTOTEN

[Art-J]

"Reject using real charts" is probably better. @Cookie01 - Caucasus map, being the oldest in the game, is full of simplifications and errors (not to mention old layouts of many airfields). The fact that navaids of various aircraft in DCS are modelled with different levels of accuracy doesn't help either.

 

Use the charts from the "doc" folder of the game, the real ones will just confuse you more.

[Cookie01]

man i really wish ED would remake the caucasus, but i doubt that'll happen in the near/mid future; they've already got enough on their plate already with the other maps
-reject using real charts - yeah my squadron adapted by correcting the runway headings on our charts by the error

but thanks for the explanation all!

[NineLine]

I am marking this as known as stated the map is quite old and a hybrid of old and new tech, because of this, issues can be apparent.