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D-ECHO Caribbean scenery edit?

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D-ECHO Caribbean scenery edit?

Postby SurferTim » Fri Jul 05, 2019 12:25 pm

Lately I have tried D-ECHO's scenery for the Windward Islands and found it quite good. Much more realistic than the stock scenery.
https://gitlab.com/decho/caribbean
However, there are some glaring runway elevation errors, and I would like to correct those. Does this download have enough data to edit his files?

I'm not asking for D-ECHO to do the edits, just show me how he does it so I can help.
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Re: D-ECHO Caribbean scenery edit?

Postby D-ECHO » Fri Jul 05, 2019 1:08 pm

The GPL license requires the data (before compilation) to be openly accessible (as far as I understand), and I try to comply with this.
The README file (at https://gitlab.com/decho/caribbean/blob/master/README) states the data sources, of which almost all can be accessed from other websites. As I noted that the manually edited airport data is not available, I've now uploaded it to https://github.com/D-ECHO/Caribbean-airports. With this information, you should be able to set up a terragear set yourself to generate these airports. Nevertheless, it might be easier and faster if you tell me (preferably in a list ;) ) which issues you have, please note though that not all might be fixable given the current terragear toolchain (no offense here, the terragear developers did an amazing job that I'm very thankful for, but manual editing the product is just not intended)
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Re: D-ECHO Caribbean scenery edit?

Postby SurferTim » Fri Jul 05, 2019 1:15 pm

First, I want to thank you for apparently a tremendous amount of work you put in on the scenery.
I don't mind you doing it. I didn't want to be a bother.
I am using the GPS elevation output to determine elevation. Is this the best way? The altimeter seems inaccurate for this.

I only have a few airports with elevation challenges. How about one at a time?
At St Bart (my favorite airport), there are runway threshold errors.
Rwy 10 threshold elevation should be 48 feet. It shows 89 feet on your scenery.
Rwy 28 threshold elevation should be 4 feet. It shows 17 feet on your scenery.
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Re: D-ECHO Caribbean scenery edit?

Postby D-ECHO » Fri Jul 05, 2019 1:26 pm

I can not manually set the elevation for specific points, it is determined by the (prone to failure) SRTM(-3) data. What I can alter is only the position (which seems okay) and the maximal slope of an airport. It thus is always a compromise between avoiding cliffs and sharp cuts, having the correct (as published) runway slope and the actual elevations.
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Re: D-ECHO Caribbean scenery edit?

Postby SurferTim » Fri Jul 05, 2019 1:36 pm

Your position is spot on. Only the elevation is off.

The stock scenery has nearly the correct elevations. How did the creators of that scenery do it?

I've seen the X-Plane version of St Bart, and it is not even close to accurate (no cliff at all), so this is significantly better than that.

However, for a small fee ($20 or so), X-Plane will be happy to sell you a "corrected version" of the St Bart airport, including the famously dangerous cliff. I wonder how they edited the elevation data?
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Re: D-ECHO Caribbean scenery edit?

Postby D-ECHO » Fri Jul 05, 2019 1:39 pm

I'm not very knowledged in X-Plane's scenery system, but they do it a bit differently afaik and also, they might use higher-resolution elevation data when you pay them ;)

The "stock" (terrasync) scenery uses a different max-slope. I can try it with some different values, but this might have other bad effects, so, as I said, it's always a compromise
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Re: D-ECHO Caribbean scenery edit?

Postby SurferTim » Fri Jul 05, 2019 1:48 pm

D-ECHO wrote in Fri Jul 05, 2019 1:39 pm:I'm not very knowledged in X-Plane's scenery system, but they do it a bit differently afaik and also, they might use higher-resolution elevation data when you pay them ;)

The "stock" (terrasync) scenery uses a different max-slope. I can try it with some different values, but this might have other bad effects, so, as I said, it's always a compromise


I'll have to look into how they edit their elevation data. They must have a way to do it if they did it for St Bart on the pay-to-play version. There isn't much on open source that can't be hacked. I hacked the live weather fail a few months ago. Good thing too. I like flying real world, and Flightgear is still on the unfixed version for Ubuntu. Maybe I can write a hack for the elevation data.

Edit: I am not that familiar with terragear or terrasync but as I understand, you can disable terrasync, correct? If that was disabled, where does fgfs get elevation data? Can you select where the app gets the elevation?
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Re: D-ECHO Caribbean scenery edit?

Postby legoboyvdlp » Fri Jul 05, 2019 1:59 pm

XPlanes methods are totally different to FlightGear's unfortunately. For instance they generate scenery runtime while we use pre-created scenery tiles made in a toolchain. The best way would be to edit the BTG files in a 3D tool such as Blender but that's not easy to implement especially as BTG is a binary format.

Someone did just make a tool in VB that will edit BTG files to remove seams :). Maybe some day this will allow us to edit terrain elevation as well.
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Re: D-ECHO Caribbean scenery edit?

Postby SurferTim » Fri Jul 05, 2019 2:07 pm

legoboyvdlp wrote in Fri Jul 05, 2019 1:59 pm:XPlanes methods are totally different to FlightGear's unfortunately. For instance they generate scenery runtime while we use pre-created scenery tiles made in a toolchain. The best way would be to edit the BTG files in a 3D tool such as Blender but that's not easy to implement especially as BTG is a binary format.

Someone did just make a tool in VB that will edit BTG files to remove seams :). Maybe some day this will allow us to edit terrain elevation as well.

That may be very helpful! Can you point me to that tool?

So what I understand is:
X-Plane loads elevation runtime.
Flightgear loads elevation from the scenery files that were created using TerraGear? So TerraGear does all the elevation, and fgfs uses that?

I fear not binary.

Edit: So if that is correct, there are two places this can be hacked.
1) the source TerraGear uses for elevation.
2) the scenery file output from TerraGear.
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Re: D-ECHO Caribbean scenery edit?

Postby legoboyvdlp » Fri Jul 05, 2019 2:21 pm

TerraGear takes elevation from SRTM data as well as shape files and airport data and converts that to BTG files. BTG files include everything - normals, materials, actual mesh.
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Re: D-ECHO Caribbean scenery edit?

Postby D-ECHO » Fri Jul 05, 2019 2:21 pm

SurferTim wrote in Fri Jul 05, 2019 2:07 pm:That may be very helpful! Can you point me to that tool?

I think legoboy is talking about this topic viewtopic.php?f=5&t=36075 :)

SurferTim wrote in Fri Jul 05, 2019 2:07 pm:
So what I understand is:
X-Plane loads elevation runtime.
Flightgear loads elevation from the scenery files that were created using TerraGear? So TerraGear does all the elevation, and fgfs uses that?

Basically yes, terragear compiles binary scenery files (.btg) from the data that is put into it (shapefiles (is it a town or a forest etc....), airports (airport layouts) and elevation data).


SurferTim wrote in Fri Jul 05, 2019 2:07 pm:Edit: So if that is correct, there are two places this can be hacked.
1) the source TerraGear uses for elevation.
2) the scenery file output from TerraGear.

Yep, think so. IIRC there is a tool to import .btg files into blender, but none to export the (changed) mesh. Searching for "edit .hgt" or similar might give you some hints for the first way.

Ah, lego you were faster ;)
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Re: D-ECHO Caribbean scenery edit?

Postby D-ECHO » Fri Jul 05, 2019 2:22 pm

SurferTim wrote in Fri Jul 05, 2019 1:48 pm:
Edit: I am not that familiar with terragear or terrasync but as I understand, you can disable terrasync, correct? If that was disabled, where does fgfs get elevation data? Can you select where the app gets the elevation?


FGFS receives scenery (meaning, complete bundled terrain made of landclasses, airports and elevation and objects which don't interest here), either by downloading the scenery seperately or by using the built-in terrasync, which is essentially just a tool that downloads the scenery files based on your current position. Disabling terrasync while having no scenery downloaded for that area will result in an all-ocean situation.
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Re: D-ECHO Caribbean scenery edit?

Postby SurferTim » Fri Jul 05, 2019 2:32 pm

D-ECHO wrote in Fri Jul 05, 2019 2:22 pm:
SurferTim wrote in Fri Jul 05, 2019 1:48 pm:
Edit: I am not that familiar with terragear or terrasync but as I understand, you can disable terrasync, correct? If that was disabled, where does fgfs get elevation data? Can you select where the app gets the elevation?


FGFS receives scenery (meaning, complete bundled terrain made of landclasses, airports and elevation and objects which don't interest here), either by downloading the scenery seperately or by using the built-in terrasync, which is essentially just a tool that downloads the scenery files based on your current position. Disabling terrasync while having no scenery downloaded for that area will result in an all-ocean situation.

Got ya!

From what I understand, fgfs will search /.fgfs/Scenery for "custom" scenery, then use terrasync. Your scenery uses the *.btg.gz files in /Terrain/w60n10 and /Terrain/w70n10, correct?

Edit: Probably backwards from that if I were to write it. Try terrasync, then overwrite that with anything found in /.fgfs/Scenery/.
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Re: D-ECHO Caribbean scenery edit?

Postby wkitty42 » Fri Jul 05, 2019 2:46 pm

talking about adjusting the terrain makes me think of the huge job that has been discussed a long time back where the terrain data is edited via a GIS database and editor... AIUI this is where the shape files come from, too... i've not yet spent any tme with my QGIS installation to fully grok terrain editing but i do know that i can layer in the shapes... just not sure about adjusting elevations... i would think so as there has to be some method of doing that to knock out the building spikes that some terrain data contains... so i guess this is one step further back than just terrain assembly...
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Re: D-ECHO Caribbean scenery edit?

Postby legoboyvdlp » Fri Jul 05, 2019 2:52 pm

Elevation is a raster format so it probably would be a matter of changing the colour of individual pixels. There might be a specific tool to edit .hgt files - if anyone knows it would definitely help :)
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