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Aliya
2012-Jan-29, 07:11 PM
I heard about Cosmoquest from the Weekly Space Hangout. (I really like the hangout, but I'm at work when it's live, so I have to watch it later. Sorry I can't "+1" it, but I do watch.)
One suggestion for the Moon Mapper-Simply Craters would be to give some tips on pinpointing the crater rims. Many of craters don't have well-defined rims and are at or near the 18 pixel lower limit, where one pixel makes a difference.

astrostu
2012-Jan-29, 08:22 PM
Hi Aliya, thanks for trying out the site and taking the time for feedback. We're working now on a small revision for marking craters. The idea is that when the "Mark Craters" tool is selected, there will be some sort of guide lines to help point out the minimum crater size as well as help you center the pointer to reduce fine-tuning later on. I can't give you any more details because they could still change.

In terms of actually doing a 17 versus 18 pixel crater, well, that comes down to you. I've definitely found myself drawing to just what I think it is, but then expanding by 1 teensy pixel just to make it go green. And then smacking myself but not deleting it. That kind of issue will be taken care of, somehow, by me later on in processing. I'm still thinking of a few different approaches I could take.

kmasterdo
2012-Jan-29, 08:33 PM
In terms of actually doing a 17 versus 18 pixel crater, well, that comes down to you. I've definitely found myself drawing to just what I think it is, but then expanding by 1 teensy pixel just to make it go green. And then smacking myself but not deleting it. That kind of issue will be taken care of, somehow, by me later on in processing. I'm still thinking of a few different approaches I could take.

I'm glad to know that I'm not alone with that kind of problem. :)

astrostu
2012-Jan-29, 08:39 PM
I'm glad to know that I'm not alone with that kind of problem. :)

It's actually pretty interesting psychologically.

kmasterdo
2012-Jan-29, 08:47 PM
It's actually pretty interesting psychologically.
Why that? Now I'm really curious. :)

astrostu
2012-Jan-29, 09:02 PM
Why that? Now I'm really curious. :)

Well, I just think it's interesting. I mean, even I, who knows EXACTLY what I'm looking for and have done this for years, will stretch the marking occasionally by a pixel just to make it count. Don't know if there's a term for that or anything, I just think it's interesting. :)

Aliya
2012-Jan-29, 10:43 PM
Well, I don't know that I'm tempted to stretch the circle to make it count. I assume the 18 pixel size is a bit artitrary, not the Chandracrater limit. I thought there might be some physical clues in the pictures to help locate the rim. If the crater is not well-delineated, I'm just guessing where I think it is.

astrostu
2012-Jan-29, 11:07 PM
Ah, my apologies for misreading your question. There are no real clues in the image as to where the rim is, it just is where it is. The sharp craters are easy to figure out, the degraded ones not so much. The example images along the bottom are attempts to help you on that issue. But, in the end, it comes down to your judgement about where you think the rim belongs. Your estimate, along with everyone else's will get averaged together to create the agglomerate crater.

And you are correct, 18 pixels is an arbitrary limit. We chose that for a few reasons: a. There wouldn't be a huge number of craters in any given image such that people just give up. b. It's somewhat doable on tablets. c. Larger craters are usually easier to see. d. There are still plenty of craters down to 18 pixels in size; these images get down to about 0.5 m/pixel, so we still expect to be able to build a database of craters down to 10 meters in diameter.

We may adjust this in the future, but for now we're sticking with 18 pixels and we're going to see how it works out.

Placidstorm
2012-Jan-30, 12:29 AM
What's the thought's on another colored crater marker for " verifiably vague under this light ." (To coin a phrase for Stu .) I think something like that might be good for cross reference . Just thinking out loud again .

kmasterdo
2012-Jan-30, 06:36 AM
Don't know if there's a term for that or anything, I just think it's interesting. :)

What about doing psychological studies on Moon Mappers? :)

StarStryder
2012-Jan-30, 07:40 AM
What are your ideas? We will be studying things like how time on image changes over time and things like that. I'm open to any other ideas you may have.

Cheers,
Pamela