The 1.5 Map

Hello,

I am learning the C++ and as a practical work I am making a tool for DCS.

It has several function as QNH / QFE conversion ( Viggen bombing), BullsEye to Braa conversion and the problem is with the last one :

I would like to calculate the bearing/distance between two point ( latitude / longitude).

I managed to calculate the exact bearing between two point with the grid correction:

The "master" meridian is the 33°E, it is the only one pointing grid North. On the Caucasus map, If you go east or west of the 33°E meridian you will have some deviation with this grid north.

To calculate the deviation at the A point the formula is :

A longitude - 33 * sin ( A lattitude)

To calculate the bearing between two point, you need to calculate the departure and arrival bearing.

To do so, have to calculate the bearing from A to B, and the bearing from B to A +180°.

After that, calculate the average value and you will obtain the bearing calculated by DCS.

To calculate the distance between the two points I use this formula :

A-B = arc cos (sin ϕA sin ϕB + cos ϕA cos ϕB cos dλ) * 6 371

But I have a deviation between the result and the distance calculated by the INS of the M-2000 and the F10Map:

The 2000's INS is more readable than the f10 Map so I used it and tested some value:

Latidude (fix):

W00 N 40:00.00

W01 N 40:09.99 <-- 09.99 and not 10.00 because of a bug changing automatically 10.00 to 09.99.

longitude :

On both WP ( W00 and W01) I use the same longitude value to have a true south to north vector.

Longitude Distance (Nm)

E 30:00.00 9.74

E 33:00.00 9.82

E 34:00.00 9.85

E 42:00.00 9.88

E 45:00.00 9.94

E 50:00.00 10.07

E 78:00.00 11.68

E 80:00.00 11.84

E 90:00.00 12.86

I hope you understand something at what I said. I have trouble expressing myself in English.

So the only problem you have is the distance? I'd say that's pretty good considering that getting bearing was the most difficult thing.

Maybe your Mirage result has some drift accumulated?

The "master" meridian is the 33°E, it is the only one pointing true North. On the Caucasus map, If you go east or west of the 33°E meridian you will have some deviation.

To calculate the deviation at the A point the formula is :

Actually thats not correct and it might prevent you from calculating things accurately.

ALL meridians point to true north, as true north is defined by meridians. The center UTM meridian ("master") is the only one pointing to grid north. Grid north is just a vertical line anywhere in the map.

Hope this helps and good job!

So the only problem you have is the distance? I'd say that's pretty good considering that getting bearing was the most difficult thing.

 

Maybe your Mirage result has some drift accumulated?

 

 

 

 

Actually thats not correct and it might prevent you from calculating things accurately.

 

ALL meridians point to true north, as true north is defined by meridians. The center UTM meridian ("master") is the only one pointing to grid north. Grid north is just a vertical line anywhere in the map.

 

 

Hope this helps and good job!

Sorry, I misspoke, and I agree with you. I edit my post!

I would gladly pay for a graphical flight planning tol, a bit like foreflight but with the DCS maps.

Hello,

 

I am learning the C++ and as a practical work I am making a tool for DCS.

It has several function as QNH / QFE conversion ( Viggen bombing), BullsEye to Braa conversion and the problem is with the last one :

 

I would like to calculate the bearing/distance between two point ( latitude / longitude).

 

I managed to calculate the exact bearing between two point with the grid correction:

 

 

The "master" meridian is the 33°E, it is the only one pointing grid North. On the Caucasus map, If you go east or west of the 33°E meridian you will have some deviation with this grid north.

To calculate the deviation at the A point the formula is :

 

A longitude - 33 * sin ( A lattitude)

 

 

To calculate the bearing between two point, you need to calculate the departure and arrival bearing.

To do so, have to calculate the bearing from A to B, and the bearing from B to A +180°.

 

 

After that, calculate the average value and you will obtain the bearing calculated by DCS.

 

 

To calculate the distance between the two points I use this formula :

A-B = arc cos (sin ϕA sin ϕB + cos ϕA cos ϕB cos dλ) * 6 371

 

But I have a deviation between the result and the distance calculated by the INS of the M-2000 and the F10Map:

 

The 2000's INS is more readable than the f10 Map so I used it and tested some value:

 

Latidude (fix):

 

W00 N 40:00.00

W01 N 40:09.99 <-- 09.99 and not 10.00 because of a bug changing automatically 10.00 to 09.99.

 

longitude :

 

On both WP ( W00 and W01) I use the same longitude value to have a true south to north vector.

 

Longitude Distance (Nm)

 

E 30:00.00 9.74

E 33:00.00 9.82

E 34:00.00 9.85

E 42:00.00 9.88

E 45:00.00 9.94

E 50:00.00 10.07

E 78:00.00 11.68

E 80:00.00 11.84

E 90:00.00 12.86

 

 

I hope you understand something at what I said. I have trouble expressing myself in English.

So, the mirage2000 INS is totally wrong. There is different value with the distance on the F10 map and the INS.

The difference between calculated distance ( like in real world) and F10 distance seems to be:

F10 Distance = calculated distance / COS(grid Deviation)

I would gladly pay for a graphical flight planning tol, a bit like foreflight but with the DCS maps.

Do you know this?

http://jboecker.github.io/dcs-mission-planner/planner_client.html