Saturday, June 06, 2009

Featured picture priorities at Wikipedia

This mosaic of Saturn's moon Titan, taken by the Cassini spacecraft in 2004, "constitutes the most detailed full-disc view of the mysterious moon". It is a featured picture at English Wikipedia, but on 1 June 2009 an editor nominated this image for delisting.

And that delisting nomination, along with the reasoning that led to it, could harm Wikipedia for years to come. It's a shortsighted trend that needs to be stopped.

This was the nominator's rationale:
Noisy, lack of detail, improper focus(?), areas of focus varying.
The first response elaborated:
Delist Woah, that is pretty rough. The stitching is also kind of obvious, especially with the error at the edge of the globe at about the WNW position. The sharp edge is also unrealistic and distracting. Is that a natural background or did NASA just replace with a single black?
In response, another commenter suggested:
If you read the page description, it says that NASA has processed the image to sharpen the surface details.
This has led to a lively debate about featured picture standards. On one side:
Delist - Agree this would make a better VP than FP. Technical quality is low - stitching errors, pixelated edges, inconsistent sharpness, grainy, etc. The EV is extremely high though.
On the other:
Keep This image is not easily reproducable. There is a lack of images of titan, possibly one of the more important bodies in this solar system. And this is currently the best composite image of the whole surface. Please do some reading up on the FPC guidelines. They are there to read, understood and applied, not to be simply ignored.
The issue here is whether esthetics take priority over encyclopedic value in the site's featured pictures. And with that debate rests the fate of the site's relatively new valued pictures program. Encyclopedic value has always been an important consideration at featured pictures and can highly encyclopedic images get priority over esthetics according to the official featured picture criteria, but that's on the verge of changing. From a related nomination to de-feature the nuclear bombing of Nagasaki:
Maybe its time we "demote" some of our lower-quality FPs and fill up VPC with them... We aren't doing harm; maybe this will be a saving grace for the VPC program.
Actually that would a great deal of harm: featured pictures get a turn on Wikipedia's main page. Valued pictures don't. That makes a big difference to the team of volunteers are negotiating with museums and archives internationally to improve access to encyclopedic images. To a museum curator, the chance of a turn on Wikipedia's main page is a golden opportunity: approximately 7 million views per day. That is very persuasive in opening doors and in obtaining large content donations to WMF of many thousands of images.

Put it this way: if you were talking to a Japanese historic archive, wouldn't it be a lot more persuasive to show them the mushroom cloud as a featured picture, and explain that if they released their collection too then their country's perspective--the destruction that actually occurred on the ground--could get equal attention on Wikipedia's main page?

The valued pictures program, which receives no main page attention, is a bureaucratic process that harms Wikipedia by hindering negotiations to gain encyclopedic content. Valued pictures has been nominated for deletion. Both Gerard Meijssen (chairman of the Open Progress Foundation) and Joseph Seddon (a board member of Wikimedia UK) have endorsed the deletion nomination. Meijssen and Seddon are both part of the international volunteer network that is working to open the doors at more image archives.


Pymouss said...

Ther's something strange in this affair. As far as I can see, the debate tokk place on enwp. Isn't Commons the correct place to stock and debate on images ?

Lise Broer said...

Wikipedia has a separate Featured Pictures program. And due to differences in site policies some images cannot be hosted at Commons.

kaldari said...

I think you may be missing the point on the Titan debate. The problem isn't that the photographic equipment wasn't good enough, its that whoever did the post-processing at NASA did a crappy job. They could easily go back to the original data and build a much higher quality image. I'm not a graphics professional, but I know for a fact that I could do a better job of stitching and masking than they did. In fact, I think just about anyone who had more than an hour to work on it could do a better job.

Lise Broer said...

Actually that's something this post addresses directly: this was created for scientific purposes, so of course it was not stitched and masked. The priority was to examine surface features; esthetic edits would have introduced variables and distracted from that.

Titan and earth are the only two bodies in the solar system that have significant surface liquid. So best practice for our encyclopedia is to preserve that mosaic as it is.

Kaldari said...

But the image clearly was stitched and masked (poorly). Most of the images that NASA releases to the public are not edited primarily for scientific value. NASA has huge databases of unedited images available to scientists (most of which the general public can't even access). The images they release to the public are post-processed (often by STScI) primarily for the media and PR value. Unfortunately, the quality of the post-processing seems to vary considerably. Although they have gotten better over the years, I have to say that the image of Titan is one of their worst.

Lise Broer said...

Probably that had something to do with the contrast enhancement and something to do with the astronomical object. NASA's statement was that this was their best full surface view of this moon.

It may be possible that they took a subsequent shot that's better and just didn't update the file description. If you locate a better replacement I'll endorse it and give you a barnstar. :)

Colin Howell said...

Durova, I think your general point in this blog entry is a good one, and some of the criticism of the Titan image does appear to have been made out of ignorance. However, I think that you and others defending this particular image may have unknowingly gone a bit overboard.

In your last comment, you said, "NASA's statement was that this was their best full surface view of this moon. ... It may be possible that they took a subsequent shot that's better and just didn't update the file description."

More precisely, the caption claims this mosaic "constitutes the most detailed full-disc view of the mysterious moon". However, that comes from the "Original Caption Released with Image". In other words, it's the caption from the initial press release for that image. The captions for NASA images on the web are often unmodified from the original press release, a fact which you have to keep in mind when reading them.

Unfortunately, the image catalog page on JPL's Photojournal lacks a date. You have to go to the catalog listing page (search for PIA06141, near the bottom) to see that this image was published on November 23, 2004. Actually, a better reference page for the image is its page from CICLOPS, since they were the group who originally produced it.

When this image was published, Cassini had only been in orbit around Saturn for a few months. It had just completed its second flyby of Titan, and another flyby would be happening in a couple of weeks. Judging from the credits for this image, it looks like it was created by scientists on the Cassini imaging team. (I recognize a couple of the names.) Based on my own experience on the Voyager imaging team during the 1989 Neptune encounter (which now feels like a lifetime ago), these people would have been busy as hell and would surely have had little time to craft a careful mosaic. They were making a quick-and-dirty product for public consumption.

Although the scientists may have found this image useful for spotting features which might deserve further study, I doubt it was intended for serious science. For that sort of work, you'd want either raw image data or a mosaic that had been carefully calibrated and properly mapped to surface locations, not a quick job like this one.

The image is still important, since at the time it was the most detailed overall mosaic of Titan's surface yet produced. But that was over 4.5 years ago. Cassini has since made tens of additional Titan flybys, and there has been lots of time for its imaging team to create better, more carefully generated mosaics from that vast store of image data. So looking for a potential replacement seems like a good idea to me.

Kaldari said...

Lise, you owe me a barnstar :)