I see a hole but no block. I guess the hole implies that the block is somewhere. They seem to say it plopped back down and got covered by some sheet of material. I can't figure how they can deduce that.

Good point. The data for the image says it is .42 m/pixel for width and 2.18 m/pixel for height. Adjusting the image gives the following...


It still looks like lines are there.

I have noticed for the high latitudes such as shown in this image, but also apparent in lots of other such images, that there appear to be lines or furrows or shadows in one direction. Is this another kind of optical illusion? The lines do not seem to be in the direction of the sun.

http://wms.lroc.asu.edu/lroc/view_lroc/LRO....0/M127825115RC

Sorry, I do not know of a win32 version. I wrote my own FORTRAN RDR reader based on the description of the RDR file. Erwan M. described to me a lot of conversions needed to create a DEM. I skip those because I need to use the raw data points for my work. Also, I found I needed to examine segments carefully with a viewer to make sure no erroneous data points were included (they are not flagged yet, perhaps in future versions).

Anyone heard when the WAC LRO stereo DEM is going to be published?

Anyone find any interesting LROC images lately? Are we all bored of boulder tracks and cave pits by now?

I saw this odd feature today which I can't figure out.

http://wms.lroc.asu.edu/lroc/view_lroc/LRO....0/M126452243LC

Just a lucky crater wall slide or some collapsed dome? Kind of hard to figure out the shadowing. I would have thought the inner ring lower than the outer rim, but then why is the ring unshadowed?


Image at 195% of original.

I follow why it is very unlikely to be a very low speed (<1km/sec) fluffy icy comet nucleus.

However, I did find an interesting paper which ran simulations on various cometary nucleus densities.

"Cometary and Meteorite Swarm Impact on Planetary Surfaces"; John D. O'Keefe/Thomas J. Ahrens; Seismological Laboratory, Division of Geological and Planetary Sciences California Institute of Technology; Journal of Geophysical Research, Vol. 87, #B8, pg 6668-6680, 1982.

They looked at densities of 1, .1 and .01 gm/cm^3. For 1 gm/cm^3 at 5-15 km/sec, the solid ice impactor presents a crater that appears like a solid silicate impactor. At 0.1 gm/cm^3, the crater is more like a disc at 5 km/sec and ring at 15 km/sec.

They state the depth/projectile diameter ratio is about the same for 5km/sec and 15 km/sec. For the maximum depth of the surface undulations, for 1 gm/cm^3, this ratio is about 1.5. For .1 gm/cm^3, the ratio is about .5. For 0.01 gm/cm^3, it is about 0.08. Thus for very low density impactors, "the mean of the excavation depth is near zero". Most of the .1 and .01 gm/cm^3 cases had flat floored craters and some with surface instabilities.

Pretty neat work for those days.

Not clear how frequent the impactor events are or what the current thinking of comet nucleus density is. Louis Franks had a rather large frequency for small comets which caused a bit of controversy.

Most is correct. But what about those going the same direction as the Moon? I seem to recall meteors hitting Earth had some better chance of survival in those cases.

Heh, this reminds me. I have heard about comets and other icy/watery objects being responsible for some of the water on the Moon (and Earth for that matter). Could this be an impact site of this sort of object? Or would they appear no different than a rock at the speeds they are travelling? Depends on the object densities I guess.

Also, the LOLA data has some heights very close to that longitude/latitude.

"I do not agree that we need to paint the whole Moon to have a realistic map at say 25m resolution."

What is the meaning of the word "realistic"? It may be realistic for people who want to render topographic surfaces for illustrative purposes or animations or simulations that do not require interacting with the surface. But I think one would not consider it realistic if one is planning a rover path or doing certain types of illumination analysis.

I think you and your team are doing great work, but I think some accuracy/realism aspects go over most users heads and are ignored.

"Indeed the current filling ratio of the 25x25m near the poles was 72% when we discussed that in June, but it will keep on improving."

This is the number I quoted before and is what bothered me because the DEMs show continuous surfaces where they cannot really be definitive as such (other than interpolation). Yes, given enough time you should get "100%" (meaning, to other readers, at least one 5 m diameter laser spot within all of the polar 25m by 25 m areal elements). But I have a little trouble with the rationale of interpolating an entire pixel height based on maybe <4% of the area being painted by laser light (i.e. one laser spot for a surface that needs 25 laser spots to fully define). Maybe the LOLA data is meant just for a certain purpose and I am trying to use it for a purpose that was not intended and I should really use the stereo imagery derived terrain instead.

>The September release in a couple of weeks will have side products for each of the DEMs containing the counts
>of laser shots in each pixel. People can use that as a mask to see where you can be more or less confident in the
>measurement averaging (actually a median).

This will be helpful.

>And having "gaps" in the DEMs to reflect the actual sampling would not necessarily make it better; I would
>expect most people want a full map, and do not want to do their own interpolation (they may not be familiar
>with the tools to do so) when they want to render a given region.

Gaps would be no good in the DEM, but what I think some users would like is the number of shots per pixel (0 shots would tell them it is pure interpolation). It would also be nice to have an error estimate for each pixel (maybe based on the difference between the interpolation pixel height and the average of the heights of the laser spots within the pixel).

>To reassure you, the data is not put through magic black boxes, and the workflow is actually pretty straightforward.

Interpolation is kind of magical in that it is hard to intuitively know how the interpolation will work out all the time for every set of points. You are not simply drawing a straight line between points, it is much more complex.

>>With coarser grids (240 m by 240 m/pixel), the percentage of surface area with laser data spots is around 8%.
>Do you mean globally? In June, polewards of ~85deg, we had ~90% coverage at that resolution.

By this I mean, for a 240m by 240 m DEM, I created a grid of 5 m non-overlapping spots to fill it which gives you 48 by 48/ 5 m spots or 2304 laser spots needed to cover the whole pixel. Then using your average number of laser spots/pixel within 25 km of the south pole (136+-63), I get a maximum of 8.6% and an average of 6% of the area painted by laser light. Sure, the number of 240m by 240m pixels that have at least 1 laser spot is ~100% in the case, but what I am saying is the kind of interpolated height based on 6-8% of the surface area needs some sort of error bar associated with it, since it is very hard for any of us to figure it out just from the raw data.

>The September release is coming very soon, and the DEMs will be updated this time, with more than 2 billion (good) points which went into them.

This is great! Still, globally, this means you are covering ~.1% of the lunar surface with laser light. So will LRO be merging the stereo imaging with LOLA data for significant regions? Are you working with those guys?

"It takes time to get it all fixed up... but people, if you want to see how unbelievable LOLA is going to be when it's all done, check out this amazing presentation from the NASA Lunar Science Forum, held at NASA Ames last month. This is by Maria Zuber, and - alas - it didn't survive the PDF-making process properly. I have asked if it can be fixed. But even so, it looks good. Check out the LOLA map of the floor of Shackleton on page 15. "


Yes, it looks good, and is much better than what we have had and they are doing great work.

But there are some points that should be emphasized (and I do not think they are sufficiently)........

For a 25 m/pixel grid for within 25 km of the South Pole,
(1) Only 72% of the grid elements have at least one laser data point. This means 28% are empty, but the DEMs show them filled (interpolated). This is a concern to me because although it creates a nice continuous image/DEM, it needs an accompanying error map to help a user to understand the missing data, interpolation error, etc.
(2) The average number of laser data points in this grid is 1.5 +- 1.4. For a 25m by 25 m pixel, you would like around 25 laser data points to get good coverage with 5 m diameter spots. This means when the DEM is constructed, the height for that pixel is supposed to be an average height of the surface, but really it is the height average of from 0% to 12% of the surface area within the pixel.
(3) How does the laser data point treats the area it "paints"? Is this the average height within the 5 m spot or the highest spot or what?


With coarser grids (240 m by 240 m/pixel), the percentage of surface area with laser data spots is around 8%.

Thus the magic of creating the DEM (i.e. sausage making) has alot of aspects that people need to realize and see if it applies to their usage. I have been stymied from doing illumination analysis because of these concerns. Sure I can do it and have done it with my analysis tools and use either the DEMs or the actual laser points, but I cannot create an error bar, so I have to reassess this laser data DEM.

Yes, this will affect my work. Thanks.

I am baffled also by the lack of data density. I am waiting for LROC stereo imagery inferred heights correlated with the LOLA data. The problem is that LOLA, even at the poles, has <.3% of the surface area "painted" by LOLA light. Interpolations of height seem somewhat unreliable based on that. Normally, one could generate nice looking 3D models without worrying about this, but doing illumination analysis and being impacted by unknown nearby terrain or planning mobility paths can't be done with LOLA alone.

I found an extra image that had not been reported elsewhere of the Mare Ingenii pit/cave/skylight/lava tube.

Here is the publicized Mare Ingenii image.



http://lroc.sese.asu.edu/news/index.php?/a...i.html#extended

Here is what I found on my own and which I have not found posted elsewhere.



Here is an overlay (somewhat poor) of the two.




Also, for the previous Marius Hills unpublished image I found, I created an overlay image.

Found this the other day and was surprised I did not see it before now.

A nice image of apparently the floor of the pit of the Marius Hills pit / Lava Tube Skylight.
I find the image kind of creepy.



http://wms.lroc.asu.edu/lroc/view_lroc/LRO....0/M122584310LE


The pit had originally been shown at a different sun angle on
http://lroc.sese.asu.edu/news/index.php?/a...e-Skylight.html

Probably USGS will do one eventually. But I am surprised some go-getter hasn't done it yet. I liked the one you did from Clementine images!

Phil,
Do you have any overlay maps generated for the south pole region yet? We seem to have enough images, but at least for me, my computer/Photoshop doesn't have enough memory (at resolution) to assemble more than 4.
James

I have been using the RDR data (not the DEMs) for lunar illumination work. You have to be careful to use the right filters.

In RDRSIS.pdf it shows the shot flags for each shot.
http://imbrium.mit.edu/DOCUMENT/RDRSIS.pdf
http://imbrium.mit.edu/LABEL/LOLARDR.FMT

Use the ones with 0 as the least significant bit. It is interesting to understand the criteria for eliminating points. There are so many shots, that it is impossible to manually filter them all. The main automated filter they include is to compare the 5 shots against each other (not against other nearby shot sets). I think the slope limit is 37 deg between shots. This does a good job on most shots.

I have looked around both poles and found some that were erroenous comared against existing LOLA data from other passes (no shots have yet been manually editted/flagged in the RDR datasets so far). If you are interested in them, I can give you a list. It isn't that big and would likely not show up if you are using a tool like GMT to process the points into a DEM (unless you are shooting for high resolution) due to the averaging and surface fitting that tool uses.

Alot of interesting images.

I came across what I like, which are side views (perhaps called limb views)....M103290270L and M103290270R;M103261640L and M103261640R. I could not find any others in the set with similar orientation.

If you adjust the contrast on these tif images, you see a slightly lighter area above the horizon. Could this be related to the levitated dust (which I don't believe has been confirmed for near the poles) or is it an artifact of the camera or even the image processing?

I just downloaded one of the tiff browse images and used Adobe Photoshop CS2 to open it. Perhaps you downloaded it in ASCII or the download was just bad or something.

From a prior LRO offering (http://wms.lroc.asu.edu/lroc_browse/view/M107985155LE), one of the tracks showed an oblong boulder that somehow bounced a considerable distance (I attach an excerpt at 2X), ~1.5 km.

I assume the boulders are fairly rigid, so what can I infer about the regolith? I remember seeing the inferred regolith characteristics from boulder tracks and they focused mainly on the width/deepness of the track and the mass of the boulder, but nothing regarding implication of bouncing boulders.

We need to get the LOLA data to understand these slopes better and start doing these calculations in earnest.

These rolling boulders are interesting. Note how the one I show here (went ~1.2 km on this image) doesn't seem too bothered by a crater but gets a course change by another toward the end. Probably due to alot of energy early in the rolling. This would make a good dynamics analysis to figure out.

What is the maximum distance a boulder could roll or bounce? I haven't seen (or can't remember seeing) that being done.

Wow, those are great! The "bouncing boulder" tracks seem to go on pretty far. Does that make sense? The sustained dynamics over such a long distance seem to be unlikely. Yet there they are!

I've been downloading and looking at them. But with no boulder tracks, I have little to report.

Also, you gotta agree that your eyes start to cross if you look at the entire image at full resolution (by stepping through it) and that if you have seen alot of craters and a few boulders, its hard to get that excited unless you really are looking for something.

I was hoping for more images near the south pole.

I am excited about the data on this page from the LOLA instrument!
http://svs.gsfc.nasa.gov/vis/a000000/a003600/a003633/

"nother LRO image

http://wms.lroc.asu.edu/lroc_browse/view/M104419352R

"The linear rille Rima Ariadaeus is found on the nearside of the Moon, nestled between Mare Tranquillitatis and Mare Vaporum."

FULL INLINE QUOTE REMOVED - ADMIN

Anyone trying to download the entire 504 Mb file should note the name is incorrect. It is...
http://lroc.sese.asu.edu/data/pr/tiff/nacl00001431.tif.tif

I think this is the area they are talking about (toward the bottom of the image). As Phil points out, directions are kind of useless near the Poles. But the upper part of the image is better illuminated due to the downward slope/Sun direction...so its the crater wall... not a good spot to land. So the more flat rim portion at the bottom of the image is a more likely spot to land, although it may not be near the best site to place the base (if we base it on having the shortest annual night period). I still need to get oriented on the image.

Didn't find any rolling boulders yet!!! Drat!!