Help on Altitude Calcluations

[High-Octane]

Guys,

I'm working wn Altitude using VB6 And I have encountered some problem on calcluation Or did I write string incorrect?? Let take a look at yje string I wrote:

Acknowledge:

Altitude, Offset Value H570, 8 data bit

String I wrote:

Dim Fake64bit As currency

Dim Altitude As Double

Dim dwResult As Long

If FSUIPC_Read(&H570, 8, VarPtr (Fake64bit), dwResult) Then

Alritude = Fake65bit * 10000#

Altitude = Altitude *360#/ (65536# * 65536#)

Altlbl.caption = (Fake64)

End If

Running FS2002/My form Creation I get:

FS2002:Alt 306

My form: 8729354 something

Obviously, I did wrong on calucation... can anyone tell me me what did I do wrong??

Thanks in advance

[rickalty]

You could always just do what I did - get the altitude from offset 3324 instead. Then you jut DIM it as Long and use it directly.

Richard

[rickalty]

Or alternatively, read a Long at 574 for the whole meters, and a Long at 570

Also, I don't see why you're doing the calculations at all - it looks to me like the whole meters are stored directly at 574, and the fractions directly at 570 - no 65536*65536 calcs needed.

Richard

[Pete Dowson]

Sorry for the delay in replying -- I've been on holiday with no Internet access. I'm just trying to catch up with an enormous backlog now!

Altitude, Offset Value H570, 8 data bit

String I wrote:

Dim Fake64bit As currency

Dim Altitude As Double

Dim dwResult As Long

If FSUIPC_Read(&H570, 8, VarPtr (Fake64bit), dwResult) Then

Alritude = Fake65bit * 10000#

Altitude = Altitude *360#/ (65536# * 65536#)

Altlbl.caption = (Fake64)

End If

The altitude there is NOT floating poiint, but fixed point. The integer in metres is 32-bits (4 bytes) at 0574, the fraction is in 0570.

Best to read it into an array of two integers. Read metres in the 2nd and the fraction (UNsigned) in 1/(65536*65536) ths in the first.

Regards,

Pete