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scott967

AFCAD altitude problems

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I've been looking at altitudes generated by AFCAD. I'm finding what appears to me to be inconistent UI and handling.1. If you set units to feet (uncheck units in meters), you can enter altitude of the AP ref point and runways (haven't tried other elements)to 0.1 feet, and internally, it appears that AFCAD is converting this to 0.01 meters. However, in the UI property sheet, the alt is rounded to 0.1 meters.2. If you set units to meters, you can enter altitude of AP ref point to 0.01 meter, though once again the display is only to 0.1 meters.3. If you set units to meters, you can enter altitude of runways, but they are displayed and saved only to the nearest meter, though they are displayed as nnn.0 in the runway properties.scott s.

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Hello Scott,Interesting observations. They certainly require more testing. Here is a portion of a new AFCAD file:[/b] And here is a part of the original, shown for comparison purposes:AFCAD seems to be doing everything correctly in this particular instance. Do you have more details that you can provide?Best regards.Luis

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Sure. First off, I've been comparing the output of JABBGL against the binary, and for the few I looked at, they agree completely.I look in NAMW at AP914140, airport KUIL (Quillayute) and JABBGL shows:Airport 59.131 Runway 59.131Open the airport in AFCAD. Set Tools > Options> metric units.Look at the airport properties -- altitude 59.1Runway properties -- altitude 59.1Do a "save as" AF2_KUIL. Look at it with JABBGL. The atitudes are correctly preserved (59.131).Now edit the airport properties altitude to 59.2 and runway properties to 59.2 and save. Now JABBGL reports the airport altitude as 59.200 and the runway as 59.000. This can be confrimed in AFCAD2, as if you reopen the runway properties, the altitude will be shown as 59.0, not 59.2 as previously entered.Now change the AFCAD options to feet.The airport properties altitude is 194.2 (ft) and runway 193.6 (ft) which mathematically convert to 59.192 and 59.009 meters, respectively. Save the file. The previous altitudes of 59.200 and 59.000 are retained.Now (while in feet) adjust the altitudes for both airport and runway to 194.0 (feet) and save. Checking in JABBGL, and I'm back to my original 59.131 meters.Now edit the file (while in feet) back to the 194.2 and 193.6 figures shown earlier and save. Now JABBGL is showing 59.191 and 59.009, inother words, what we would expect.conclusions:What you see in AFCAD is not what you get. Unedited values are preserved from the default values, but may not be displayed correctly, depending on the choice of meters or feet.Editing in "feet" provides greater accuracy than editing in "meters".Editing runway altitudes in meters does not retain tenths units.The same displayed altitude value may actually contain different values, depending on if the value was edited or not.Note that all my edits were done on the same file, with periodic saves. It may be that if you save and reload the saved file, it may display differently. I haven't tried all the possible combinations.My recommendation, at least for US airports, is to edit them in feet, and check the result in JABBGL to verify the altitudes are as expected. I don't know if Lee Swordy is still in the flight sim business, but it would be nice to have AFCAD display the full accuracy of .001 meterscand advise if the internal representation is also in meters or actually feet. Since BGLCOMP allows either unit, it could be either, but since the output of BGLCOMP is in meters, it would be nice to use that as the internal format I would think.scott s..

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The problem is that both JABBGL and Afcad2 convert the floating point values from the bgl to decimal ASCII with a different precision. This value (decimal) may be converted back to floating point if edited.If you wish to retain your precision, edit the XML directly and enter the alt values to whatever precision you wish in either feet or metres.This conversion process affects all values. If you keep re-editing with Afcad, you will find that the nodes will gradually move from their original positions.George

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Thanks Luis,Your earlier thread on altitudes and the difference between the LWM3 scaling and XML scaling is what led me to look more closely at AFCAD. Also, I've been having problems with using XML derived rom AFCAD within SGX, and vice-versa. I started by looking at the XML generated by BGLXML and NewBGLAnalyze and saw that they didn't match, so I started digging deeper. That's when I started using JABBGL rather than trusting the other tools. As you indicate, the airport facility data in the FS9 XML format is not a float, but is saved as INT32 as integer number of millimeters. Since the XSD allows use of an "F" flag in the input, BGLCOMP can convert feet to meters at compile time. Looking at some of the default airports, I suspect that this is what MS did, since I don't think there is any source data accurate to .001M. I might hand code some XML and just prove to myself that the F to M conversion is working OK but I have no reason to assume it isn't.Now I've been off on this goose chase so long, I can't remember where I was in my original problem, which was trying to fix some problems I was having using a scenery (MKE2004) in FS9.scott s..

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