HRSC DEM Movies Options

[Nix]

Ah, THE mountain... I'm eager to see what's coming. Glad to know you won't be bothered with ram issues.

Nico

[ngunn]

actually getting it right on 1x elev isn't too problematic either.

That's good. I'd like to see at least some at 1x. Getting a feel for the true gradients is important if one wants to set ones mind to wondering about slope stability, fluidity of lava flows and the like. (I've never managed to make any sense of Venus because of having my head filled with grossly vertically stretched Magellan imagery right from the start.)

Anyhow - wonderful stuff. Keep it coming!

[djellison]

http://hrscview.fu-berlin.de/cgi-bin/ion-p?page=entry.ion will always let you look at them in 1x perspective. The problem is, 99% of them are dull as dishwater when you do that

Doug

[djellison]

http://www.rlproject.com/HRSC/37/0037_ol_hi.mov (16.4 meg)
http://www.rlproject.com/HRSC/37/0037_ol_lo.mov (6 meg)

[djellison]

Tonight - Eberswalde Crater with a CTX swathe on top, and maybe Nilli Fossae, probably without a CTX swathe on top.

They'll render tomorrow - and we're off playing Guitar Hero 3 tomorrow night, so they'll have to wait till Thursday

Doug

[djellison]

The texture for Eberswalde took for ever.

Just for you Nige - comparing 1x and 3x elevation at Nili Fossae (one of the MSL landing site proposals). Sat down, did the maths, made sure it was the right total altitude and that the difference between max and min altitiude matched the file headers.

I've actually set both of these rendering in full. The problem is getting the cameras to match exactly. (you can stretch a terrain vertically quite easily, but not the path that a camera takes) so not the exact same view, but it's the same frame number from two very similar animations.

You can probably guess which is the most accurate I can make to the actual, and which is 3x exag of that

For reference, this entire swath is 119.7km wide, 1059 km long - has a max altitude of -857m and a min altitude of -6866m (which I turn into adjusted altitiude based on the hrsc2tif idl module adding a value to make them all positive) - So a terrain altitude 'range' of 6 km from highest to lowest on the whole swath. i.e. 0.6% of the length - hence why they can be a bit dull.

Those swath dimensions refer to this entire box in which the map projected image sits - http://pds-geosciences.wustl.edu/mex/mex-m...88_0000_gr3.jpg - I create an alpha channel for the terrain to remove the crap off the edges, as the displacement process goes nuts with the edge of the elevation map ( hence all the little funky jagged hedges around the edge of most of these )


Doug

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[ElkGroveDan]

I think for maximum esthetic value you need something between 1.5 and 2.5. 1 is certainly too flat and 3 is rather tortured.

[djellison]

This is the first frame + a middle-ish frame of the Eberswalde anim - the landing site, very roughly, markes with a white circle (which vanished after 2 secs) - you can see the CTX swath in there. Sadly - I couldn't get 3ds to handle the 23k x 32k tif I wanted to use - so it's at 50% of that.

This + 2 x Nili for Friday probably.

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[ngunn]

Thanks Doug. So, EGD, Mars is too flat for ya?

[charborob]

I think for maximum esthetic value you need something between 1.5 and 2.5. 1 is certainly too flat and 3 is rather tortured.

For my part, I would rather see Mars as it really is, without vertical exaggeration.

[djellison]

And the HRSCView website will let you do that, to all the dem's they've got

Doug

[peter59]

I'm sorry that I don't share your delight. Not to shabby, but it's only animation, notting more. I prefer to watch real MRO's data (many times better) using IAS Viewer's functions "Create Waypoints" and "Waypoint following". For example, I suggest planning journey from west to east over Cerberus Fossae (PSP_003650_1900) with magnification 1:2. It's better and real movie.

[djellison]

real MRO's data (many times better)

There's nothing 'fake' about this data. I've not made any part of it up - it all comes straight from the actuall data provided by the HRSC team.

HiRISE imagery is many times higher resolution ( 100 - 200 x better resolution ) - but based on that argument, perhaps we shoudl take Themis, HRSC, CTX and MARCI and turn them all off. Only HiRISE provides that resolution, so everything else must be useless, right

I don't think anyone is claiming this is the 'best' data, nor the 'best' way to look at it - but it's something new being done with a fascinating and growing data set. Scrolling around HiRISE imagery with the viewer is another way to look at a different dataset that shows us different things from a different spacial perspective. What's unique about HiRISE is that the imagery is immediately made sense of by even an uninformed human brain as it is of a resolution that we can interpret in real terms. What's unique about HRSC is that it matches moderate resolution and higher resolution elevation data.

Now - DEM's with HiRISE imagery (which will hopefully make it 'out' at some point) would be the best of both worlds - astonishing resolution in every dimension ( except time ). But even that isn't the 'best' or 'most real' way to look at Mars.

Doug

[slinted]

...but it's something new being done with a fascinating and growing data set.

Cheers to that! By adding topographic information, the already impressive, voluminous (and overwhelming) data returned by HRSC becomes that much more valuable both in scientific and outreach potential. I'm excited that the addition of the DTEMs has inspired you to dig in and share the best of what is available. Keep it up

[TheChemist]

Not everybody has the time to scroll through HiRISE imagery with the viewer, so Doug's work is highly appreciated here...
Thanks Doug, and keep it up !