[X] My Assistant

[Phil Stooke]

I thought this subject might deserve its own topic. John-s made several matches between features seen in Spirit images south of Husband Hill. Then I suggested that a specific feature seen in those pans (I provide an approximately reprojected map-geometry version of the pan) might be Home Plate:



Object B is what i think is Home Plate. The flanks but not the summit of Ramon Hill appear beyond it.

There might be some errors in my attempted matches, but many seem good to me. It's quite hard to reconcile panoramic and overhead topography in this way, even towards Bonneville.

I would really welcome any other attempts to match features like this, to see if we can resolve the question... if B in the pan is not Home Plate, what is it?

Phil

[fredk]

Another thought occurs to me: Dilo's projection should involve just one parameter: the height of spirit above "the plain". So it should be possible to constrain the height by adjusting that parameter until the feature positions agree with the orbital imagery (perhaps this is what you did, dilo).

But in reality, the "plain" will have some tilt and curvature. In principle, we should be able to recover this info from a single good-quality pan. I see it working this way: assume first the plains are truly flat. Adjust the rover height parameter to obtain the "best fit" between reliably identified features in pan and orbital images. Some of those features will be too low, and some too high, due to departures from flatness. Then simply adjust the height of each feature individually, up or down, and reproject, until the match is exact between the pan and orbital imagery. This gives us a set of points with well-determined elevations, which could be used to construct an elevation contour plot or whatever.

Really, what this amounts to is an extreme form of stereo imaging: one view from the rover in the hills, the other view from orbit! In fact, it should be simple to construct visual analglyphs along these lines.

Clearly this would be limited by how precisely we could identify features. Sounds like a project for a summer student!

[dilo]

Fredk, I used exactly this method to argue the height of Spirit over the plain in a previous thread 3 weeks ago (see ).
In this case I "guessed" the new quote and than I verified that, on average, there is an acceptable scale agreement with satellite image...
The extreme stereographic method you suggests is interesting, but probably has many limitations, first of all the different albedo of some features (like craters inside) when observed at low incidence angle... this make it hard to automatize, but is good for a summer student!