Boundary record in XML

[Guest jirpe]

Hi,It was discussed here 3 month ago with no conclusion. So I will try to continue. I wonder how are the frequencies (and names) connected to boundaries. I decompiled bvfc.bgl with bglxml, took first boundary and compiled it back. Then I compared the result with the entry from the original file. Result is attached (RTF file).It's evident that Boundary record in the original file contains both name (MURMANSK) and frequency. It's not described in SDK, maybe bglcomp itself cannot generate such record, but it's there.It's also obvious that data about frequency and name are pretty similar (if not same) as the standard Com record, look what's there:12 00 = ID for COM14 00 00 00 = record size0A 00 = Com type CENTER20 57 90 07 = frequency 126.9than follows the name (MURMANSK)Rest of data is in fact sameThus I think, that Boundary record can contain standard Com record which defines the frequency and 'user friendly' name.I tried also to modify bglcomp.xsd adding com element into the grpBoundaryChildren. And then I included Com into the Boundary in the XML file, but here I was unsuccesful. Even if schema is modified, bglcomp still reports that Com element is not allowed within Boundary. I'm not sure if bglcomp really takes xsd from the same directory where it is started from (from current directory), but I think so.Does anybody here has any suggestion what next to try.

[arno 1]

Hi,Interesting finds :). I am not sure if adding things to the BGLComp.xsd file really works, but if we know enough about the format of the BGL file we can also make some excludes for BGLC that allow you to write new files.I will try to take a look at the BGL format myself the comming days and let you know if I find anything.

[Guest jirpe]

Adding record into schema file really doesn't help. XML is OK against the schema but bglcomp doesn't know what to do with such record. Unfortunatelly. I will try to modify the bgl with the hex editor, perhaps I will find something more.

[Guest jirpe]

Hello Arno,I just wrote a simple C program which adds the COM record into the Boundary section of the BGL. It's a really alpha version, expects BGL has only one section, no subsections and so on. But it works, ATC reports:Tune Center on 127.700Missing name is probably because of missing voice pack entry.So my observation is that the COM record must be just after the maximumAltitude element of the Boundary section, but before type field (0x19)btw. program itself as well as the source are available upon request

[Guest christian]

Dunno why I didn't see this post earlier...I've played with this about 1-2 years ago and came to the same conclusion. In theory bglcomp should allow for coms in boundary files but doesn't and yes modifying the xsd doesn't work, its a bug in bglcomp.The hex structure is quite straight forward, but I see you've solved the problem already. Tracking back to the time when I was playing with this - I completely redid the NZ and Cook Island airspace (the at90cen files which contain control areas etc). What I found odd was that the boundaries in this file don't seem to be linked to frequencies or agents at all. And extending the control zones didn't seem to trigger ATC further out either (ie adding bigger circles mushroom like didn't seem to bring up the transition airspace level X option in the ATC box where it should). Everything shows up fine on the map and correct airspace types are used, but I still to date have the nagging feeling there is a bit more to airspaces than we know.Any thoughts?Cheers,Christian

[arno 1]

Hi Christian,The last time I tried to modify the ATC structure was still with Fs2002 (using your decompiler and the little tool I made to visualize the data).I must say I haven't tried it again in the new Fs2004 format. Also for Fs2002 it gave a lot of trouble. It seems MS has not really made the ATC data part so that we can extend or modify it easy. But it is sure an interesting subject, so I hope to find some time to take a new look at it again soon.

[mgh 89]

I followed the earlier thread on this sbject and still have an interest.I have only flown FS in the UK and Europe and it seems to me that, at present, it requests transfers to other ATC frequencies on the basis of distance.Can anyone answer a fundamental question which is, even if we can get BGLCOMP to process a frequency associated with a boundary what will FS do with it?According to the SDK, the boundary types include APPROACH, CENTER, CLEARANCE, DEPARTURE, GROUND, and TOWER. These also appear as frequency types. Presumably assigning CENTER to a boundary would have the effect of requiring an aircraft to use that frequency when within the boundary. It would require the bottom of the boundary to be above ground level. Aircraft could use aerodrome frquencies on the ground and when airborne below it. A change of frequency to the CENTER could be ordered when the aircraft climbed into the boundary. Approach could be different. Often an aircraft is descended in a stack by one controller and removed from the stack by another. Thus the frequency change would be needed before the aircraft left the bottom of the boundary.What would be the expected effect of assigning TOWER with an associated frequency to a boundary type?