Problem with "Podhořany" Tutorial

Moderators: Uros, OXO, JBr

Post Reply
buteo
Posts: 15
Joined: Sun May 08, 2005 10:15 am

Problem with "Podhořany" Tutorial

Post by buteo » Wed Jul 03, 2019 12:49 pm

Hello all,

trying to work through the landscape creation tutorial (Condor Landscape Guide rev1a.pdf), I am stuck at a late stage; perhaps someone can help?

In QGIS (latest version 3.8.0, which may be part of the problem?), all goes well.
After importing the data from Earth Explorer and reprojecting and clipping them as per the tutorial, I export them to another BIL (= RAW) file, setting the output format to INT16 (unsigned 16-bit word), thus not using the QGIS default (FLOAT32).
The resulting BIL file has the precisely correct size (NROWS*NCOLS*2, in this case 1536*1536*2 bytes).
It is then processed further with RawToTrn, again with no apparent problems or error messages.
And the terrain still looks correct in this tool.

However, this is where something seems to go wrong: If I then load the TRN file into the Landscape Editor, I do not see the terrain (as in QGIS and as seen on other Landscape Editor screenshots here on the forum), but instead just a chaotic jumble of pixels:
pic1.jpg
If I deselect (View menu item) "Draw textures", I only see a uniformly grey area and the patch/tiles grid, but still no terrain.
I added the airport anyway, added an *.ini and a *.cup file to the landscape folder, did all the exports (mostly dummy files at this stage), and then tried to test the scenery in Condor (airborne start).

The Flight Planner also does not show the terrain properly (to be expected):
pic2.jpg
The flight test basically works: The landscape even shows some kind of terrain, but I think it is not as it should look. Of course there are still no textures at this point, so everything will be uniformly grey, but I would expect a smoother shading (a landscape "covered with uniform grey texture and [...] void of any details", as the tutorial says), not these "Morse code" patterns:
pic3.jpg
Once proper textures are applied, it all looks more normal, but I am still wondering if the terrain (now covered with textures) is actually the one it should be. (I can't be sure as I do not know the real area around Podhořany, but it all looks far too flat.)

In other words, before or without textures, should I not be seeing smooth terrain shading?
If so, what am I overlooking and/or doing wrong?

Thanks in advance for any pointers and tips!
You do not have the required permissions to view the files attached to this post.

User avatar
Cadfael
Posts: 3703
Joined: Fri May 27, 2005 8:07 pm
Location: Czech republic
Contact:

Re: Problem with "Podhořany" Tutorial

Post by Cadfael » Wed Jul 03, 2019 2:21 pm

I am not sure, but I am afraid at the later QGIS versions is not possible modify parameters for warp reproject

Resampling method cubic cpline
Then click on the pencil in the lower right of the dialog
to edit the command
Enter "-tr 30 30" after EHdr
You do not have the required permissions to view the files attached to this post.
Image
Image

buteo
Posts: 15
Joined: Sun May 08, 2005 10:15 am

Re: Problem with "Podhořany" Tutorial

Post by buteo » Wed Jul 03, 2019 3:15 pm

Thanks for the quick reply!

The newer QGIS versions do indeed no longer allow one to directly edit the "GDAL/OGR console call" text (and thus there is no pencil icon any more), but I discovered it can still be done:
The Warp dialog now has an optional field "Output file resolution in target georeferenced units".
aa.png

If you fill in "30.0" there, this will then turn up below in the "console call" text as "-tr 30.0 30.0":
bb.png
I think I did that, so it may not be the issue here, but I will double-check.
May be there are still other differences with newer QGIS versions?
You do not have the required permissions to view the files attached to this post.

User avatar
Cadfael
Posts: 3703
Joined: Fri May 27, 2005 8:07 pm
Location: Czech republic
Contact:

Re: Problem with "Podhořany" Tutorial

Post by Cadfael » Wed Jul 03, 2019 6:45 pm

Thank for info about Output file resolution. I was not working with trn a year or so, but be sure you did not exchange X and Y parameters at rawtotrn. This must be any simply mistake during a process I think
Image
Image

User avatar
Andy1248
Posts: 1423
Joined: Wed Nov 29, 2006 3:06 pm
Location: Biggleswade, Bedfordshire

Re: Problem with "Podhořany" Tutorial

Post by Andy1248 » Wed Jul 03, 2019 7:38 pm

Best I can recommend is to download and use the QGIS version as advised in the guide. Then it all should work OK.
Condor CN = E20

buteo
Posts: 15
Joined: Sun May 08, 2005 10:15 am

Re: Problem with "Podhořany" Tutorial [SOLVED]

Post by buteo » Thu Jul 04, 2019 11:20 am

be sure you did not exchange X and Y parameters
Indeed, that turned out to be the problem: X and Y were OK; but ymin and ymax were accidentally swapped :oops:
(UTM coordinates are too long for my taste... :D )
Now all works as advertised.
Thanks for the help!

@Andy: Thanks for the reply. But at least in this specific case the newer QGIS version was thus not the problem.

User avatar
Andy1248
Posts: 1423
Joined: Wed Nov 29, 2006 3:06 pm
Location: Biggleswade, Bedfordshire

Re: Problem with "Podhořany" Tutorial

Post by Andy1248 » Thu Jul 04, 2019 2:23 pm

:D
Condor CN = E20

Post Reply