Airports on Plateaus

[Bob Artim]

The mesh is great stuff, however a lot of the airports I see are now up on a plateau. Is there something that can be done about this? I am under the impression that FSX brings the ground up to the airport so I tried changing the elevation of one with the new AFX program from Flight 1, but it didnt do anything. I have also been reading about making a new airport and needing to "flatten" the land. A utility called SbuilderX is supposed to make a flatten for a new airport but I havent gotten that far yet.

The airport I have been playing with is SPIL in Quinceville Peru. It is sitting up on a 2000 foot cliff.

[JustinFSG]

HI Bob,

The problem is that airports in real life are never perfectly flat, yet perfectly flat is the only way FS can depict airports (at least not without highly complex programming gymnastics and even then not really.

This FAQ on the old site explains it pretty well:

http://portal.fsgenesis.net/index.php?name=FAQ&id_cat=10#q38

That said, I am developing a process that should massage the terrain surrounding these airports to lessen the effect a bit.  Summer activities ate into my production time considerably this year, but now that the kids are back in school I'm ramping things up again and should begin issuing these fixes as discovered and needed during September.

And quinceville, yes, it's extreme.  When I researched i found that the FS devs fudged the airport's elevation by some 1600 feet to match thier inaccurate terrain.  Shame, too, since that is the departure airport for the Amazon Trek mission.  I'll have another look at it and see if I can't fix it easily with flight1's new airport utility.

Hope this helps

[Bob Artim]

Thanks for replying Justin, but your link is out of commission due to some attack?

So then your saying your going to fix these airports, or I should say the surrounding scenery elevations?

Is there nothing I can do to the scenery? As I say I tried changing airport elevation but it did nothing. There are over 24,000 airports in FSX, I dont think you want to do all that work, if so your not charging enough for the mesh.

[JustinFSG]

Well, what needs fixing on most of these airports is the flatness, but it's not really possible to "fix" the flatness, since the graphics engine won't allow it, probably until next version of FS, so to fix most of these problems one must fudge the terrain surrounding them.  There are cases where the airports are simply at the wrong elevation, or have the wrong orientation, or are misplaced by some KMs, and those things can be fixed, but most of the plateau you'll see are a result of flatness, not elevation or location.

BTW, the link works for me.

[JustinFSG]

Here's the text of the FAQ noted earlier in case the link isn't working for you:

I've just installed your terrain mesh. Why do some of the runways at some of my airports appear to be sitting on plateaus?

In most cases, the terrain is accurate but the airport's elevation isn't.
This is usually due to the "flat runway" limitation of FS. Since the airport's listed elevation is usually the highest point o­n the airport grounds, and isn't necessarily the same as the airport's runway threshold elevations, which invariably are all different, or the elevation of the rest of the airport in real life.

Airport's in real life are never perfectly-flat, yet that's the only thing FS can depict--perfectly flat airport and runways. Since the FS database uses the highest elevation o­n the airport grounds, the result is the plateau effect in some instances when highly-detailed and highly-accurate terrain is applied.

As an example, go to airnav.com and look up Davis-Monthan AFB in Tucson. Go there is FS and note the elevation at one end of the runway is perfect, but at the other end it's on a plateau. Note the threshold elevations of the ends of the runway at Airnav.com. They are over 100 feet different. Since FS can only depict a perfectly flat runway, one end is on a plateau.

Just something we have to live with until FS comes up with a way to depict runways and airports as they are in real life--uneven.

[Marc "Cole" W.]

Link doesn't work for me either, it says :

Site Disabled

Temporarily closed to investigate unknown attack

[Bob Artim]

The link still doesnt work I get

Site Disabled



Temporarily closed to investigate unknown attack
   
but thanks for posting what the link would have said.

I have been researching this problem, and found a program called SbuilderX and here is a tutorial link for it.

http://library.avsim.net/download.php?DLID=105771

The last 3 pages of the tutorial shows our problem and how to fix it. He removes the "flatten" from the airport and makes a new AFCAD file and places it in SCENERY/WORLD/SCENERY so it is read before any Addon Scenery.

This would be an incredible amount of work to do all airports, but not bad for just a few that were you favorites. AIrports in extremely mountainous terrain are the worst and those are usually very small strips out in the middle of no where.

Either way I am not giving up my FSGenesis meshes or landclass, they made FSX like a whole new program, I can live with the a few plateaus until something is worked out.

[Mace]

tried changing the elevation of one with the new AFX program from Flight 1, but it didnt do anything. I have also been reading about making a new airport and needing to "flatten" the land. A utility called SbuilderX is supposed to make a flatten for a new airport but I havent gotten that far yet.

Hello

AFX by Flight1 will not do that.

To do that, you need a program like FSX_KML, or SbuilderX as you mentioned.  (Actually technically you don't need any program, as you can do it with Shp2Vec utility included in the SDK.)

The airport I have been playing with is SPIL in Quinceville Peru. It is sitting up on a 2000 foot cliff.

Many, many remote and small airports in FS (any version) simply have incorrect elevations applied to them.

You see that with Catacamas (Honduras) and many others.

Part of the problem is inaccurate reporting data (for example, in the USA, many rural airfields elevations are based on what the airport owner or manager reports to the FAA.  This data is not always accurate.)  You can imagine how unreliable elevation data is in even more remote corners of the Earth.

The best way to find the approximate elevation (short of travelling there with a GPS and/or calibrated altimeter...) is to temporarily eliminate the airport in FS.   

Then look at FSG's terrain mesh at the site...this will give you a pretty close estimation of the layout and elevation.

For Quinceville I am sure it would be quite different than where Microsoft put their flatten.

[Mace]

That said, I am developing a process that should massage the terrain surrounding these airports to lessen the effect a bit. 

Hi Justin

Would this entail slightly raising the terrain around the airport to lessen the "plateau" effect?

It is very evident on my MPTO scenery.  I had to explain to some users exactly what you said about sloped runways, etc.  unfortunately the elevation of MPTO is 41.0 meters, which is the HIGHEST point on the field.  In real life, most of the airport is much much lower.

However, I feel I *must* use published airport elevations in any airport I design, for a number of reasons.

[JustinFSG]

I agree.  Unfortunately this flat-airport limitation causes us to make all kinds of realism compromises that will disappear when FS finally has the ability to depict airports as they are in real life -- uneven.  What further muddies the situation is the fact that the airport's published elevation rarely has anything to do with the runways threshold elevations, which often vary by up to 200 feet!  Thus the flat-airport limitation creates a situation where one is danged if we do, danged if we don't.  Since the airport must be flat we can either raise the whole airport to match the highest runway's threshold elevation (creating a plateau on the other end), or we can lower it to the lowest runway's threshold elevation (creating a ditch).  Either way, it's wrong.

What I am proposing to do is leave the airports as they are and massage the surrounding terrain to slope up gradually towards the flatten poly.  These will be separate, small files layered above the real terrain so as not to have to completely rework the terrain for next version of FS, which I believe will finally have the ability to depict airports with true accuracy.

[Mace]

I have been lobbying for depiction of sloped runways in FS.  I hope it is in the next version.  But it would require a lot of reworking of the AI system and the way taxiways/runways are implemented.

I think if you could massage the local terrain at certain airports to match that would be a nice thing.  But then again, if you do it, you are danged if you do...because the "massaging" would put higher terrain aroudn the airport.

I wanted to adjust the terrain with my MPTO scenery on the south side of the airport but it's been about 4 years since I messed with terrain mesh design, and I haven't had time to get into things down there.

Rhett

[mattius]

I have the mesh from Visualflights VFR Terrain installed in FSX, (as well as the USA Canada from FSG!) If you take Lyneham, (EGDL), then the whole airport is higher than the surround. Can this be flattened with a flatten command or not? If so I would like some techo to talk me through it.

[Garrett67]

I haven't flown much since installing FSGenesis earlier today but is the adverse affect common (as noted below)? This is (HI13) Puu Waa Waa in Hawaii.

[dboley]

A previous message in this thread had a link to a tutorial. The trick after changing the elevations of the usual stuff - airport, runway, FSX continues with the wrong elevation. The first few lines of the actual XML code (compiled/converted to BGL) for the airport need to be repeated in another file that is loaded early before your new BGL. Once you understand the tools it just becomes the usual copy paste pain.

However, this DOES NOT cure many issues where the airport is actually at the proper altitude/elevation/height. To fix that you need to build sloping land either Down To or Down From the airport. Sbuilder FS9 or X is an excellent tool for this activity. Once again tedious. This could be automated with a preselection of slopes made available. It does work for airports that are correct and is visually effective.

The other issue is the ragged edges on airports. Here a smoothed mesh around the boundary of the airport may help. Fake out FSX to think that it is a very hi-res mesh and I think that may give your smooth edges so the plateaus do not look so bad. Or, maybe do the opposite and surround the airport with lo-res mesh to reduce, instead of integrate, the ragged mesh points. Problem is that the lo-res stuff could extend over 100 meters from the airport boundaries.

[Avance]

Hello,
a lot of the airports I see are now up on a plateau... and many lakes too (South America) ! ;(



Is there a patch to correct it ?