Archive by Author | Meg

A little bit fan and a little bit blotch

We’ve been reviewing the output coming from the full Planet Four data reduction pipeline now that we’ve frozen development on the fan and blotch clustering codes. Once we have the fan markings and blotch markings clustered individually, we then have a stage that combines the individual clusters to decide it a source marked by Planet Four volunteers is really a blotch or fan by find clusters where there centers on top of each other and then depending on how many fan markings went into the fan cluster and how many markings went into the blotch cluster we decide it’s a fan or a blotch for the final catalog. What we found in the catalog review that there are nice cases where there are sources that aren’t quite a fan only or not just a blotch. With a citizen science approach we’re able to capture that fuzziness  which is fantastic. We highlight a few examples below selected by Michael Aye, who has been hard at work developing this pipeline over the past several years.

In all three figures: the top left is the Planet Four subject image, top middle is all the individual volunteer fan markings, top right is all the individual volunteer blotch markings, the bottom right is the blotch clusters after clustering, the middle bottom is the fan clusters after clustering, and the bottom left is the final sources after combining the fans and blotches (the dots in this panel show the center position of the final fan or blotch in our catalog).

Image credit: Michael Aye

Image credit: Michael Aye

Image credit: Michael Aye

As you can see from above, we’re making great progress on the Planet Four data reduction pipeline. Next steps including handing the fact that the edges of most of our Planet Four subject images overlap with neighboring subject images, and ensuring that we merge overlapping volunteer markings covering the same spot on two different subject images.

Happy 2nd Birthday Planet Four: Terrains

Happy Birthday Planet Four: Terrains! Last Thursday marked the second anniversary of the launch of Planet Four: Terrains. Thank you for all of your help over the past two years. We couldn’t do this without you. To celebrate here’s a recipe for a Martian South Polar Trifle for you to make for your own Mars party. It’s inspired by this recipe:

  • 1 package (20 ounce) chocolate cream filled cookies like Oreos or Hydrox
  • 16 ounces of cream cheese
  • 1/4 cup of unsalted butter
  • 2 cups of  powdered sugar
  • 2 small packages of instant vanilla pudding mix
  • 3.5  cups milk (recommend dairy milk  – skim to whole works fine)
  • 1 tub (20 ounce) of whipped topping (not canned whipped topping but the kind you find in the freezer section). ( You can also make your own from scratch using whipping cream if you like. Just add a little bit of powdered sugar mixed in to taste)

Making the ground layer: Place chocolate cream filled cookie in a bowl or plastic bag, saving 4-6 cookies for the top later. Use a rolling pin, bottom of a glass, etc to crush the cookies. Place 3/4 of the crushed cookies on the bottom of a nine-inch glass pie plate or any glass container so you can see through the sides if possible.

Making the seasonal ice sheet mixed with seasonal ice and boulder: Soften the butter., then mix together cream cheese, butter, and powdered sugar until smooth (electric mixer or whisk is fine). With whisk combine the pudding mix with the milk until smooth and slightly thickened. Fold together cream cheese mixture, whip topping, and pudding mixture.  Add 2-3 drops of  red food coloring to get a light red color (the red food color and the power sugar represent the atmospheric dust trapped in the ice sheet). Then mix in the remaining 1/4 of the crushed cookies to represent boulders trapped in the ice sheet. Pour the mixture over the ground layer of cookies.

Topping of seasonal fans: Crush the remaining few cookies very finely, sprinkle on the top to create seasonal fan shapes

Refrigerate the trifle for 3 hours or more before serving.




The inspiration – seasonal fans in the South Polar region as imaged by HiRISE in the Southern spring or summer.

More progress on the blotch clustering

I’ve been reviewing output from the blotch clustering with updated parameters, and the good news is the two problematic cases we were trying to have the clustering algorithm identify now are successful:

We’re looking a bunch of parameters, but the bottom left corner configuration is the parameters we think are best for the blotches and and fans.

Here we are showing just the clustering of the fan markings.

Here we are showing just the clustering of the blotch markings

Here we show the clustering of the blotch markings. Now the 2-scale  blotch clustering identifies the volunteer draft markings for the large blotch below as well as smaller ones.

I think we’re at the point of locking development of the blotch pipeline. This will be a big step forward towards finishing the first paper and getting science results out of Planet Four.  We’ll want to take a look at the next stage of the pipeline after two different types of markings are cluster and the algorithm picks the final shapes based on the number of classifiers who drew fans versus blotches for the same source. If that looks good as we expect it should from previous reviews of the pipeline output, then the next thing we need to do is look at the pipeline results near the edges of each of the cutouts where this is overlap between the different subject images.


Wind streaks in Planet Four: Ridges

Perusing Planet Four: Ridges Talk I came across the image below. I thought I’d say more about it in case you encounter similar types of images. What drew my eye was the large diffuse lighter streaker on the one side of the crater.

That’s called a wind streak. Wind streaks have been found not only on Mars but also on Venus and Earth.  As their name implies, they are formed directly by the interactions of the surface wind with the soil. The wind is impacted by obstacles in its path on the surface like crater rims. As the wind moves around the crater rim either picks up dust particles pushing them together collecting them to create bright streaks visible from orbit or the wind  excavates material exposing a darker material than the surrounding top surface layer.  Wind streaks extend into into the direction the wind is moving towards, so they are also good indicators of past wind direction.


Ziggy Stardust and the Spiders from Mars – David Bowie was right!

Today we have a guest post by Planet Four volunteer Peter Jalowiczor.

Why Ziggy Stardust and the Spiders from Mars? As we know Ziggy Stardust is David Bowie’s alter ego, a rock star who acts as a messenger for extraterrestrial beings. Unfortunately, no extraterrestrial beings have been found on Mars (at the time of writing, at least!). But spiders have definitely been discovered…

From this then, as a Planet Four contributor for a number of years now, I recently put together a talk about the P4 Project to be given at my local Astronomical Society: the MSAS (Mexborough and Swinton Astronomical Society). The society is based about 20km from Sheffield (pop. 570,000), England and was founded in 1978. Every Thursday evening is a social occasion centered around a talk.  Members, such as myself are encouraged to give talks on different subjects. Usually once a month, an academic visits the society to lecture on an aspect of Astronomy. In March this year the MSAS held a ‘Back to Basics Workshop’ in conjunction with the BAA (British Astronomical Association).

Back to the talk: my initial presentation was to be a preliminary discussion about Mars in general, before focusing on the results (images) from the HiRISE (High Resolution Imaging Science Experiment).

After letting Meg know of my P4 talk, I was very kindly sent lecture materials over from Hawaii. and on June 1st did my best to interpret and present one of Meg’s lectures: ‘Exploring Mars with 150,000 Earthlings’. This was Meg’s lecture at the ‘Imiloa Astronomy Center of Hawaii  from February. It was an introduction to the Planet Four Project and collaboration with over 150,000 citizen scientist volunteers worldwide. Describing how, by the power of the internet, volunteers map the fans and other surface features formed by carbon dioxide jets helping planetary scientists characterize surface features on Mars. There was also a discussion of the other Mars projects: Terrains and Ridges and how people can get involved in exploring Mars from the comfort of their own home.


Photo courtesy: Jeremy Robinson, MSAS Member.

Photo courtesy: Jeremy Robinson, MSAS Member.

Photos from just before start of the lecture are included here. On an evening where I was competing against the British weather – but this time it was a very beautiful, warm sunny evening (something to be cherished in the UK) so the turnout wasn’t that bad. The society was very interested in the research carried out by the team and is grateful to Meg for the material.

Update on the Planet Four: Terrains Paper

A quick update on the Planet Four: Terrains paper. For the past month or so the team has been working on making changes to the manuscript and creating new figures to address the concerns of the two independent referees who reviewed the paper. The referees are experts in the field who assess and critique the paper. Having an independent set of eyes give feedback is useful and makes the paper better. We’ve submitted the revised draft on May 16th with a list of each of the changes we made to address the points raised by the referees. We’re waiting to hear back from the journal.  We hope that after this first round of review/edits that there will be only minor changes requested going forward. We’ll have to wait for the referees’ to read the revised manuscript and our report and send their assessment to the editor.  Fingers crossed for a speedy review.

As a teaser, below is a new figure we made for the paper.  The image is a subframe from a HiRISE observation of one of the regions targeted based on your classifications on Planet Four: Terrains. You can see that this area is like Inca City where we see fans emanating from a top the ice sheet where boulders are embedded/below the ice sheet. Not all the boulders exhibit seasonal fan/carbon dioxide jet activity when this image was taken

Screen Shot 2017-05-28 at 12.42.27 PM

Image credit: HiRISE/University of Arizona/JPL

Towards Finalizing the Planet Four Clustering Algorithm

The science team is making great progress towards freezing developing of the Planet Four clustering algorithm. I reviewed some of the output from the pipeline Michael Aye has been writing. Basically the task was to check on the few issues we were working on addressing by having a two size regime clustering for blotches drawn by volunteeers and pick the parameters that seemed to work best for the data.The good news is we see an improvement.

I thought I’d share some of then plots so you so you can see how close we are to finalizing the pipeline. These plots are at the stage of clustering all the blotch markings alone and then clustering all the fan markings alone. We combine the fans and blotch markings into one later on in the process. For now we’ve just run the first part of the clustering pipeline and outputted the results to these figures.  As you can see we’re doing pretty well at picking up all the fans and blotches marked by the majority of the classifiers who made a marking on the subject image.

We’ve got one or two more tweaks we brainstormed in the last science team call last week, and once we review those I think we’ll be freezing development on this part of the Planet Four analysis pipeline until after the first paper is submitted.

APF0000fwc_blotch_anglesTrue_radiiTrue pbr_fan_anglesTrue_radiiTrue pbr_blotch_anglesTrue_radiiTrue 1b0_blotch_anglesTrue_radiiTrue

Progress on the Planet Four blotch clustering

We wanted to give a quick update on the original Planet Four. Michael Aye has been leading the development of the data analysis pipeline. As previously mentioned, we’ve hit a major milestone with completing the fan clustering algorithm for combining your classifications together.  We think we’ve now hit that point for finalizing the blotch clustering algorithm.

We think we’ve now got a decent solution for addressing how to cluster very large blotches that take up half the image and very small blotches that are the default blotch circle size. Currently how we’re tackling this is clustering with one linking radius for the center of the blotch markings, and then we run the analysis again using a much larger linking radius. Here’s an example output:

Image credit: Michael Aye

This blotch clustering strategy seems to be a good compromise for our science goals and needs. We’re going to review several more test cases and if all goes well with this  step, we will freeze development on the clustering pipeline. That’s one of the last hurdles to applying the pipeline to all of your classifications and dive into what the shapes and sizes and directions of the fans and blotches tell us about the seasonal carbon dioxide jet process and the surface winds in the Martian South Polar region.

New Images on Planet Four: Ridges

Thanks for everyone’s patience while we worked on getting new images on the Planet Four: Ridges website. The data is now live on the site. This set of images is the 2nd third of the new search region we’ve been focusing on. This search region includes  two of the three remaining potential landing sites for the NASA’s next Mars rover, called Mars 2020.  You can learn more about the region in this blog post. Dive in and search for polygonal ridges today on

Planet Four Progress

We wanted to give a quick update on Planet Four. Our main focus has been to get a data reduction pipeline that robustly clusters all the volunteer drawn markings of each subject image together to identify the seasonal fans and blotches and based on the majority shape select decide if the feature is a fan or a blotch. Michael Aye has been leading this effort. We’re pleased to say that that the main fan identification portion of the analysis pipeline is complete. We still have a few more things Michael has been working on  for the  blotch identification part. We think we’ve come up with a decent solution for identifying small and very large blotches. We hope to have this part of the analysis pipeline finalized soon.  Then we will be able to apply the pipeline to all of your classifications and dive into what the shapes and sizes and directions of the fans and blotches tell us about the seasonal carbon dioxide jet process and the surface winds in the Martian South Polar region.


Normalized distribution  of fan lengths based on volunteer markings from a specific HiRISE image – Image credit: Michael Aye and Anya Portyankina