Georeferenced data test

[bigben]

Even on Mars they do donuts 

Google Earth is looking like a useful too for tracking down/previewing data for Mars. The HRSC and Hirise DTMs and imagery are used in the model.

I've set wget loose on the HRSC elevation data 

[bobbystahr]

Even on Mars they do donuts 

Google Earth is looking like a useful too for tracking down/previewing data for Mars. The HRSC and Hirise DTMs and imagery are used in the model.

I've set wget loose on the HRSC elevation data 

Heh heh heh, reorienting the rover no doubt but it has a very red neck human signature about it...And wow again...never thought of taking a GoogleShip to Mars...

[TheBadger]

Hey Ben, sorry, but I'm confused by the threads. Which part of which thread are you posting as a share? the stuff here or file sharing? I thought mars, then I thought the grand canyon. But now I'm not sure which thread I'm typing in! OK, going back to sleep now

[bigben]

This thread's about the tests I'm doing on preparing real elevation for data optimised for TG, so that includes both earth and mars.  The terrains I posted recently in File sharing are a global earth set and the Grand Canyon. I'll try and post a terrain set soon that illustrates the findings I've come up with so far (using mulitple geotiffs to provide a variable LoD terrain for a large area with "very low" RAM usage). At the moment though I'm working on sorting out a few issues with the raw data for Mars.

And speaking of which, another milestone was reached on the red planet with this World Cup-inspired post: http://hirise.lpl.arizona.edu/ESP_037117_1755. This really illustrates the insane resolution of the imagery.  A bit disappointing that they put a yellow dot on top of the rover but you can still see it (and its tracks). http://static.uahirise.org/images/2014/details/cut/ESP_037117_1755-4.jpg 

I have the data for this crater now, pity it's in the middle of nowhere but it'll be interesting to compare.

[bigben]

Finally figured out how to get Global Mapper to merge data nicely which is proving to be a critical step, both in terms of dealing with the large differences in resolution between datasets and small variations between individual data files.

First image is a render of merged mola128 and HRSC data from an altitude of 50km. The HRSC tiles vary between 25 and 75m per pixel.  Second image includes hirise data that has been overlayed without feathering the edges. Camera altitude is 1km and you can easily see the discrepancies in altitude at the edge of the tiles. Foreground data was exported at 4m per pixel.  Screengrabs are from Global Mapper showing mola128 and feathered HRSC data. You can see the distribution of the different resolutions

Turned out to be a lot more pre-processing than I expected but it's starting to come together.

[bobbystahr]

Well y got me watching for sure.....nice seeing the various stages, shows how much has gone into the final comp.

[TheBadger]

Very nice indeed. The banding is a bit of a concern, but the detail is undeniable still. Check out this video, also using HIRISE data, but apparently with even more detailed data (perhaps the data just in Candor Chasma is better?): https://www.youtube.com/watch?v=0WsjeJiAR4E
No major banding either...


Edit: this one is pretty incredible as well: https://www.youtube.com/watch?v=QutMf79sFhk
Or check out the crazy detail in the rocky talus slopes in this crater! https://www.youtube.com/watch?v=ftS4rujxJWo

- Oshyan

Those are very  very cool!

@ben
Im looking forward to when you get the maps put together the way you want, and also start talking about adding color information and fractal detail.
I am guessing that you will add NASA provided color info, since using just color shaders and nodes to limit color by slope and stuff would be very difficult to get right. And the earlier images you posted are full color. But I can't guess at what your close in details will look like with the color info. Just as good?.. The last three images above are very inspiring.

Also very interested to see what you and others will do with adding fractal displacements for the fine detail. Lots of room for creativity beyond loading maps and coloring!

As for me, I always wanted to build a very detailed satellite model and have it over a TG world in low orbit. Or even a spaceship entering orbit as in the beginning of the Prometheus film. What your doing here will really make that look good!

[bigben]

I think the handling of data and images will probably keep me busy enough. I'm interested in repeating some of those videos in TG3. They're based on a single DTM and texture so they've wimped out a little  , and the terrain resolution looks a little low but it's very hard to judge with a texture overlay.  But image textures, even at this resolution, can be limiting when it comes to ground level, and consume a lot of RAM which then limits the available resources for TG to add finer detail.

[Edit] watched th videos at work with a faster connection and now I can see the full res data... pretty sweet [/edit]

But there are others with more TG skills than me  (http://www.planetside.co.uk/forums/index.php/topic,15070.0.html) who can benefit from this. I'm more of a technical tinkerer.

[bigben]

OK, a quick test to illustrate the potential of TG for rendering Mars data. The youtube animations linked in this thread are all of single hi res DTMs. In some instances there is a considerable loss of context from the surrounding terrain. Here's a quick render of Candor Chasma (3m/px) with and without surrounding MOLA data (900x600km chunk at 128px/°).  So for an extra 11mb of (LZW-compressed) geotiff you get to see that it actually is the floor of a deep chasm.

[Oshyan]

Wow, now *that* is a great (dramatic) illustration! If ever there was a use case for multi-resolution data merging...

- Oshyan

[bigben]

Yes, I got inspired to dress this up a little, add HRSC data into the mix and render a spherical panorama from the middle of this DTM. Looking good so far, although I still have to try the image texture map.

[bobbystahr]

Agree, WOW...great leap forwards. Can't wait to see it tex mapped.

[bigben]

Agree, WOW...great leap forwards. Can't wait to see it tex mapped.

Got an error that someone had replied since I started writing.... now where was I? 

Got a little impatient to see my georeferencing attempt and cancelled the spherical render.  This illustrates what I was saying about the texture disguising the resolution of the terrain.

First image is the terrain with a plain grey surface. Second image has 2 greyscale textures from the hirise image: 4x3km of 47cm/px and 12x8km of 3m/px. The sphere is 2m in diameter, terrain resolution at the camera is 1.9m/px.

[bobbystahr]

Guess that was me. I reiterate...WOW

[bigben]

Testing some comparative scenes from http://www.youtube.com/watch?v=0WsjeJiAR4E.  The Youtube video show just a single terrain and a false-colour image map.  I'vel loaded up TG with the full res terrain and image and some surrounding terrain (still one image set to go)

This one is around 1:07