How to recreate a piece of real terrain?

Started by KirillK, September 03, 2018, 08:54:10 am

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KirillK

What's is the right way now?  Where to grab the best resolution sources currently?

   I see I can import heightmap of both img and adf   from  https://viewer.nationalmap.gov    but how am I supposed to match color texture or a topo map  at least ( for forest coverage for example)  and where is  the best source for them?       I recall people could grab a color image from google earth before ( in sketchup) but looks like it's not an option anymore.



Oshyan

The National Map Viewer and Earth Explorer both have color (satellite) imagery that includes georeferencing just like the terrain does. So to get it to align you would just load each of them into the respective Georeference-enabled shader. In the case of terrain, Geog Heightfield Load (Add Terrain -> Heightfield (load DEM)). In the case of satellite imagery, you apply color in the Shaders layout, and you want to Add Layer -> Colour Shader -> Geog Image Map. Then make sure "Georeference" is enabled in both and they should line up automatically in Terragen. Note however that they may appear far from your camera position since georeferencing places them in their real-world location on the planet. You may need to either move your camera, or adjust the "lat/long at apex" of the planet OR change the georeferencing offset manually. There is a lot of discussion of all of this elsewhere on the forums.

- Oshyan

KirillK

Thanks Oshyan.   That "Georeference" option seems not available in Free version.   Can I get a trial of full version somehow?   If it works for me it could be an incentive to upgrade my old Terragen2 license.

Oshyan


KirillK

September 12, 2018, 05:44:31 am #4 Last Edit: September 12, 2018, 06:01:05 am by KirillK
Thanks Oshyan, I got the pro trial.   Still I have a problem. I can load and see .adf or .img  elevation formats  from https://viewer.nationalmap.gov/basic/    just ok. Pasting SW corner coordinates in Planets "Lat long at apex" makes it instantly next to  camera default position as described in the help.
    But the free color NAIP ( National Agriculture Imagery Program jp2 files) ones are loaded somewhere I even can't find on the planet.  Not matching elevation ones at all .   Should I do something special?  Switch coordinate system or something?   I bet they should be pretty typical ones.

Weirdly I see completely different numbers  in SW  and such corners in Terragen for .adf and .jp2 files  downloaded from basically same place in https://viewer.nationalmap.gov/basic/      while Jp2 color texture has numbers in the file naming itself suspiciously close to what I see in .adf corners. So I wonder what am I missing?   

ps. Whatever I was able to google regarding the issue seems related to older USGS file formats or something. So I wonder if any current approach tutorial exists somewhere?


Oshyan

Do those images appear at 0,0,0 if you disable their georeferencing? I don't have experience with the specific files or issues you're referring to and we've had no other reports of it, so it may be something specific to that data set (as you say, an older data set), or may be a bug in our handling of georeferencing that is simply rare. Can you provide more details on the *specific* data you're downloading so we can test?

- Oshyan

KirillK

September 13, 2018, 08:27:26 pm #6 Last Edit: September 13, 2018, 09:02:42 pm by KirillK
Yes, those NAIP jp2 color textures do appear in sight ( 0,0,0 position)  once I switch from georeference to position explicitly.  And the files are not old.
   I downloaded them few days ago  from USGS current web site  https://viewer.nationalmap.gov/basic/.      So I bet  it's what they distribute currently. 
Just tried to download files for another US place and it's all the same, nothing specific  for any  place I  might be downloaded from or  possible errors in my original files.

       I think those NAIP jp2 images just have kind of different georeferencing  system or something   comparing to elevation formats. 

I personally have no idea where this georeferencing is stored, where Terragen finds it and how it supposed to works  so not sure what details I could provide.  Please, could you try to download something from  https://viewer.nationalmap.gov/basic/    just to check if it works on your side.       I guess it's supposed  to be working feature   in Terragen and nationalmap is a typical source.


ps. I tried elevation of  1/3 arcsecond and NAIP color textures


Oshyan

I am testing the .jp2 you provided and will let you know if I can address the issue or find any other details, bugs, etc.

In the meantime I do have a thought/suggestion: if you download the color photo imagery for the same location as a DEM, then once you load all of them you can use "Center on object or shader" in the right-click menu of the 3D preview to move the camera to where the DEM is (it doesn't work with Geog Image Map shaders unfortunately, hence this technique). You want to do this *without* offsetting the georef to 0,0,0. Your camera may end up inside the planet, but try to see if you can move and reorient it so you see the loaded DEM, and then you should hopefully see the JP2 on top of it. That's assuming it's loading correctly, of course. The thing about these images is they cover only a few km, so they could be *very* hard to find on the whole planet without some kind of reference/starting point like this.

- Oshyan

Oshyan

Update: as an example, the image as a *single pixel* in a 2000x2000 pixel render from orbit. This is when Georef is turned *off*, so it's definitely rendering the image correctly, but it would be impossible to find at this point. It becomes barely a bit more visible with the image at 10x its actual, real-world size.

Having said all that, it's certainly still possible that it's just not rendering correctly when georeferenced. We're still investigating.

- Oshyan

KirillK

September 16, 2018, 08:06:38 pm #10 Last Edit: September 16, 2018, 08:10:37 pm by KirillK
I tried your method   and still don't see jp2 image anywhere.    They do smaller than 1/3 arcsec elevation ones so you need a few of them to cover elevation piece.   Also they come with a xml sidefile like this one for  previous Jp2:     https://www.dropbox.com/s/zebm9uor25rkltw/m_3611729_sw_11_h_20160703_20161004.xml?dl=0

   I don't see any metadata at all in jp2 itself, just RGB channels + infrared one.  Photoshop opens them as a grayscale image of 4 channels.      So wonder where it's supposed to get its georeferencing info from , maybe from this XML?   

ps.  https://www.dropbox.com/s/gi5yad1pahwsvuy/w001001.adf?dl=0      it's the DEM file  I expected to see aligned with jp2 one

Oshyan

OK, thanks for checking. We are looking into it and may need to update our GIS data import library.

- Oshyan

KirillK


Oshyan

The Mac/GIS dev was not able to get to it until this week. Will hopefully have more info soon.

- Oshyan

sboerner

KirillK - The jp2 file just seems to be a big dumb Jpeg 2000 file. I downloaded one out of curiosity and couldn't see any metadata attached to it when I opened it in Photoshop. But you were right about the related XML file. If you open that (in any plain text editor) you will see this element:

      <bounding>
        <westbc>-77.8750</westbc>
        <eastbc>-77.8125</eastbc>
        <northbc>43.2500</northbc>
        <southbc>43.1875</southbc>
      </bounding>

Just plug these values into your geog image map shader:

[attach=1]

And load the DEM file. When I did this they seemed to line up just fine:

[attach=2]

Maybe the software wizards at Planetside can automate this down the road.

These are large files. I wouldn't want to try loading more than a couple at a time.