Correcting Airport Elevation - Help!

[Guest TheExpatriate]

I apologize if this is not the correct forum for this question, but how do I correct an error in the elevation of a default airport. The airport in question is Ban Houeisay (VLHS) in Laos. It seems when Microsoft made this airport for FS9, the designer misread the elevation data as 420 FEET instead of 420 METERS. How do I fix this? All I want to do is fix the elevation for this particular airport, I do want to have to spend hours learning about scenery design for something I'll never do again. So a quick and dirty solution is what I'm looking for.Thanks in advance!

[scruffyduck 4]

Have you made a search for this? It is a common question that get's asked a lot and I am sure has been answered here before.You are going to need to make a small bgl file that contains the basic airport information and the new elevation. This needs to be placed in the default scenery folders so that it is read before the stock airport. In most cases FS takes the last value that it reads (so usually from somewhere in the Addon Scenery area) but for elevation it takes the first value it reads. Thus you create the small bgl file and place it so that FS reads that first.For a more complete explanation try the search.

[Guest TheExpatriate]

Thank you for the reply. I did a search and I quickly ended up over my head. If I use afcad and change the elevation from there, is that only going to change the elevation of the runway or of the whole airport?Any advice you have to give would be appreciated.Thanks.

[LuisFelizTirado 33]

Unfortunately, there is no "quick and dirty" solution for this, or rather, it is particularly dirty, and you will have to learn some new concepts and techniques that will take time.Airport elevation is located in different places: - the airport flatten. This is a polygon that levels the area of the airport to a uniform height, because FS airports cannot yet have a slope; - the facilities file, where there is an elevation value for the ARP, the runways, and the start positions.All these elevations have the same value, of course, taking into account the different methods for indicating the value.To change the airport elevation, you must: 1. exclude the flatten, and draw another with the new elevation. Then, 2. create a new facilities file (with AFCAD, if you wish) that has the new elevation values for the ARP, runways, and start positions.However, this is not enough! There is a problem with FS - it reads the elevation of the default facilities file first, and then does not read any other subsequent facilities elevation value. So, you will be stuck with the default elevation if you only use the above method to modify the airport.There is a work-around: create a very short facilities file with only airport identifiers, ARP elevation, runways and start position, and then place that file in the scenery library so that it is read by FS before the default facilities file.Good luck with your project.Best regards.Luis

[scott967 62]

If you are using default mesh for this area try this attached zip file.scott s..

[Guest TheExpatriate]

Wow! Thank you, Scott! It works like a charm. Thanks so much for your work. I'm sure you will quickly earn the appreciation of all of us sim-pilots who like to fly in Laos!Thanks again!

[scott967 62]

Da nada. For you or anyone else interested, this is what I did:I use LWMViewer2 to load all the files in the area and see what the default terrain looks like. In this case I confirmed that the airport was in a hole. The surrounding terrain (using the default mesh file) was varying from about 348m to 389m. (I could also use TCalc2004 while slewing in FS9 to read out ground elevations.) Based on this, I figured setting the airport to 370m would minimize the plateau/hole effect.I use sbuilder ver 2.05r6 to load the default flatten for the area of Laos, sceneyasiasceneryFL974240.bgl (LWMViewer tells you what the specific file names are, but FL9 are always airport flattens).In sbuilder, I combine the polygons which make up the flatten for VLHS (in this case there are only two), and set the propertied to elevation of 370m. I select this polygon only (remember, all the flattens for the whole file are loaded) and compile it into a bgl file.Next, I open the default airport in AFCAD 2.02. I open the aiport properties and set the altitude to 370.1m (it's good to have the airport slightly higher than the flatten to avoid texture flashing of the ground-level scenery like runways). I open the runway properties and set the same altitude here, and also both of the "starts". Then I save the AFCAD file, which results in compiling the new bgl.These two files are all that's required, but there can be problems with FS9 reading only the default airport (nd elevation) and using it for certain things like placing AI aircraft at the airport (it can also cause things like floating runways). The fix for that is to place a small verison of the same modified AFCAD file in the default folder. The only information needed for this is the airport element information with the corrected altitude. Unfortunately, there is no easy way to get what you want for this directly from AFCAD2. I use a different tool, much like AFCAD, called SceneGenX build 61. With this tool I can load the default aiport (much like in AFCAD), but with this tool I can save the text-based "xml" code for the airport. I can edit this file so it only include the airport parent element, change the altitude to 370.1m (make sure you use the same as your mod AFCAD file) and drop it on the bglcomp program (included with SceneGenX) to create the third file. this is the one that goes into (in this example) sceneryasiascenery. The first two files can go into any active scenery area. You can create a new area and activate it in the scenery library, or just place the files in addon sceneryscenery (this method is simple, but if you do this with many different scenery addons it can be hard to remember which file was part of which scenery. I only use the addon scenery area for testing.) scott s..