LONG SHOT - USA East/West NavData

[Midcon113]

I've been thinking about a project for a long time and I need some insight. Here's the grand vision:

I want to build a version of FS that is accurate for commercial aviation as it existed between 1990 and 2000 (basically prior to 9/11, which fundamentally changed commercial aviation forever). I'm primarily interested in modeling this for North America, though I'd love to expand this world wide. Eventually, this would include period-accurate AI traffic, in addition to period-accurate navdata.

Since GPS was new, restrictive and not widely available at this time, the navaid situation - at least here in the US - was completely different than it is today. And since the NGA no longer makes DAFIF files available I'm kind of stuck on the nav data that's accurate to this time frame. One solution that I'm contemplating is extracting the navdata from subLOGIC's USA East and USA West scenery, which would at least cover the CONUS. But since that data format is more than 25 years old, I'm pretty much in the dark as to how to extract that data. I have it, but I'm seeking advice on how to extract it. I remember how back then we didn't use latitude and longitude, just "scenery coordinates." I don't remember if there were any tools to either evaluate these files, or convert the data to lat/long.

As a side note, I'd love to get the data for Denver Stapleton. While in the real world my first job out of college was working with the City of Denver on the new airport (still some of my fondest memories), Stapleton was the Denver airport back then.

So that's the ask - does anyone know or have any kind of programs or ideas on how to extract that old data format into something that can be used in - you guessed it - MSFS 2020. That's stage two. If I can get the data out and into like XML format, then the next stage will be to figure out how to import it into MSFS.

Thanks for any insight - thank you all!

Mark

 

[doshea]

One solution that I'm contemplating is extracting the navdata from subLOGIC's USA East and USA West scenery, which would at least cover the CONUS. But since that data format is more than 25 years old, I'm pretty much in the dark as to how to extract that data. I have it, but I'm seeking advice on how to extract it. I remember how back then we didn't use latitude and longitude, just "scenery coordinates." I don't remember if there were any tools to either evaluate these files, or convert the data to lat/long.

There's a tool that runs under DOS called "FSDECODE":

                                   FSDECODE
                    DECODER FOR MICROSOFT FLIGHT SIMULATOR
                                  DATA FILES
...
   WHAT FSDECODE DOES

   FSDECODE reads a Flight Simulator data file (.SC1, .SCN, .DY1, .DYN, .DEM,
.MOD...), chops it in fields each containing a single value and outputs a field
contents description to an ASCII text file.  To do that, FSDECODE, which has
almost no specific knowlegde about FS data file structures, uses a description
file (thereafter called ".DES file") which tells the program how long each data
field is, what it contains and how it has to be formatted in the output.  By
default, FSDECODE selects a description file according to the input file exten-
sion, but a specific description file can be indicated.

I got the vague impression that there were two different releases of (each of) USA East and West, only one of which worked with Flight Simulator 4. I assume that if you have one that works with FS4, you could decode it using the above tool, or perhaps use the FSDECODE documentation and .DES files to understand the file format and write your own decoder (which is something I hope to do one day myself).

Here's a small snippet of FSDECODE's output for Flight Simulator 4's F1 file including stuff that you're interested in:

        --------------------
         SCENERY  PROCEDURE
        --------------------
0201F1  21 000F                                              Jump +15 at 020200
0201F4  0292 D2B0 D864 029A FF52 0898                          on HiEast  outside  4784 -  6244 OR HiNorth outside 16210 - 18584
020200  25 02F2 0F4A                                         Set var 02F2 to 0F4A
020205  25 02F4 0BBC                                         Set var 02F4 to 0BBC
02020A  3E 0014 07A4 D57C 01F4                               ===JUMP +20 at 02021E if outside 18340N  5500E +-500FSu (128000m)
020213  05 0338 D57C.0000 07A4.0000                          NDB:   0338kHz,  5500.0000E 18340.0000N
02021E  3E 0014 079D D57C 01F4                               ===JUMP +20 at 020232 if outside 18333N  5500E +-500FSu (128000m)
020227  1D 15.70 D57C.0000 079D.0000                         VOR: 115.70MHz,  5500.0000E 18333.0000N
020232  3E 0014 06EE D5C5 01F4                               ===JUMP +20 at 020246 if outside 18158N  5573E +-500FSu (128000m)
02023B  1D 09.80 D5C5.0000 06EE.0000                         VOR: 109.80MHz,  5573.0000E 18158.0000N

I think the JUMPs are there because the scenery is itself executable code, and the jumps ensure the navaids are only created if you are within a certain range of them.

You can get FSDECODE at:
- https://www.flightsim.com/files/file/1352-fsdecode-decoder-for-fs4-data-files/ (I suppose this is a well-known site but you have to register before you can download)
- http://discmaster.textfiles.com/browse/19670/RENO2.ISO/fs/utility/fsdecode.zip (no registration required, and here you can look at the documentation before you download if you want; in case you're not aware, discmaster indexes archive.org, and I did a search using it and there were lots of matches on different shovelware CDs, but they were all identical, so probably identical to whatever I downloaded a few years ago)

Yes, I assume the coordinates are all those specific coordinates used in FS4. I think I saw conversion information online somewhere once; wasn't (0, 0) being Bruce Artwick's office or something like that?

So that's the ask - does anyone know or have any kind of programs or ideas on how to extract that old data format into something that can be used in - you guessed it - MSFS 2020. That's stage two. If I can get the data out and into like XML format, then the next stage will be to figure out how to import it into MSFS.

Unfortunately the above isn't XML or even very machine-readable, and I don't know anything (and probably never will) about modern MSFS. I suppose all the navaids are probably in a pretty consistent format that you could parse out of the FSDECODE text output though.

One day I'd like to write some more modern software which can do something like FSDECODE but generate machine-readable output (XML or similar) so I can make a map viewer.