Archive | May 2015

Goodbye Manhattan, Welcome Back to Ithaca

We’ve been focusing on Manhattan for the past few months, with the aim to finish Season 4 and any remaining images of areas surrounding Manhattan in Season 1. We’ve made a big push in the last few months to finish Manhattan, and thanks to your help, we’ve completed all publicly released seasons of Manhattan.

With four seasons of Manhattan to add to the four seasons of Inca City that you’ve helped classify, we now have a rich dataset to start looking at how  geyser formation evolves over time and how the process of fans and blotch  changes from Mars year to Mars year.

Planet Four is  leaving Manhattan for now, but we’ll be back for Season 5 some time in the future. We’re going back to focus on another target of interest, Ithaca. We started classifying Ithaca Season 1 images last year, and they’re now back on the site for your to map fans and blotches.  You can learn more about Ithaca here. The most telling difference between Ithaca and other areas on Mars’ south pole is the giant fans.

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Dive into Ithaca today at

The Cerberus Fossae


The focus of this post will be on the area of the Martian surface that Planet Four: Craters volunteers have been marking craters on, the Cerberus Fossae.

The Cerberus Fossae is a set of west-north-west trending and almost parallel fissures or fractures that cut across the Cerberus plains on Mars. Evidence suggests that the fissures have been formed by faults that pulled the crust apart in the Cerberus region (9°N, 197°W).

Ripples seen at the bottom of the fault are sand blown by the wind. The underlying cause for the faulting was believed to be magma pressure related to the formation of the Elysium volcanic field, located to the northwest. The faults pass through pre-existing features such as hills, indicating that they are a young feature by the standards of those found on the surface.

In fact, this area of Mars has been identified as having the youngest volcanic plains on Mars. Early crater-counting efforts have suggested that the youngest lava surfaces in the area are less than 10 million years old. This is why it is of such interest to future missions to Mars, as a location where seismic activity might still be happening. To help predict the amount of seismic activity to expect, we need your crater markings to make a more accurate estimate of the age of the region.

If you have any other questions regarding some of the things you have spotted on Planet Four: Craters, please feel free to ask on Talk, and in the mean time please keep marking on!


Mark your calendars – 2 months until ZooCon 2015

Today officially marks two months until ZooCon 2015 hosted at the University of Oxford by the UK Zooniverse team.  It’s a day dedicated to volunteers and inspired by Zooniverse projects.

There will be some science team members (physically and virtually) from many of the Zooniverse projects talking about the recent progress and science results coming from your clicks. Some of the core Zooniverse team will be in attendance to give you updates on the latest news in the Zooniverse and where it is heading in the future.

After the afternoon discussions, attendees can later head over to a gathering at a local pub for a social evening. If talks aren’t your thing you can skip them and sign up just for the attending the pub event starting at 5pm, where you can meet  other Zooniverse volunteers and get to know some of the dedicated people who build and run the Zooniverse.

To give you an idea of what ZooCon is like check out this guest post  by our Talk  moderator Andy Martin (wassock), who attended ZooCon13. Also you can find the video of the ZooCon13 and ZooCon 14 Planet Four talks here and here. We don’t know if Planet four will be one of the projects featured (since there’s 30 projects to choose from!), but either way there will be lots of citizen science and Zooniverse happenings to talk about on July 11th.

ZooCon is set for Saturday,  July 11, 2015 from 13:00 to 21:00 (BST).There isn’t a published schedule of talks yet, but whether you’re interested in out of this world Zooniverse projects or ones closer to home, they’d love to have you join them in Oxford, UK. Tickets are free, but there is limited seating, so register if you want to attend. Reserve your spot today here.

Planet Four Season 2 and Season 3 Site Statistics

Are you ever curious to know how people classify on Planet Four? Well today is your day. I’m working on generating the final numbers for the first half of the Planet Four science paper in preparation. The paper is an introduction to the project and will contain the catalog of blotches and fans identified thanks to your help in Season 2 and Season 3. We’re getting closer to having the paper and the final catalog preparation in shape for submission by the end of the summer.

As part of the paper,  I wrote the section that talks about the classification rate and how people classify on the site. So I made a few close-to-final plots and calculated some relevant numbers from the classification database for Season 2 and 3 that will be included in the paper so I thought I’d share them here. These values and figures below are pretty close what will be in the submitted science paper.

We had a total of 3,517,363 classifications for Seasons 2 and 3 combined.  More blotches than fans were drawn, 3,483,724 blotches compared to  2,825,930 fans. With a total of 84604 unique ip addresses and registered volunteers who contributed to Planet Four when Season 2 and Season 3 titles were in rotation.  Most classifiers don’t log in. There is no difference between the non-logged in and and logged-in experience on Planet Four other than that if you classify with your Zooniverse account we can then give you credit for your contributions in the acknowledgement website we’ll make for the first paper, and we can only get your name (if you allow the Zooniverse to print it to acknowledge your effort)  if you classify with a Zooniverse account.

First plot shows the distribution of  the classifications for each tile in Season 2 and Season 3. You can see the impact of BBC Stargazing. Most of our classifications for Season 2 and Season 3 came from the period during and the few months after BBC Stargazing live and the site was getting lots of classifications and attention so we retired titles after more classifications than now. Currently a tile needs 30 classifications before we retire it, a number that better suits our current classification rate. You can see that nearly all of the Season 2 and Season 3 have 30 classifications or more, with a range of total classifications that we have to take into account when doing the data analysis and identifying the final set of blotches and fans from your markings since some tiles will have significantly more people looking at it than others.


The next plot shows the distributions of classifications for logged-in and non-logged in (without a Zooniverse account) classifiers combined for Season 2 and Season 3. We have a way to track roughly the number of classifications a non-logged in session does so I count them as a separate ‘volunteer’ in this plot (note I cut the plot off at 100 classifications for visibility). 

You can see that most people only do a few classifications and leave and there is a distribution and a tail of volunteers who do more work. That’s typical of the participation in most websites on the Internet About 80% of our classifications come from people who do more than 50 classifications, typical of many Zooniverse projects.  Both the people that contribute a few clicks and those that contribute more are valuable to the project and help us identify the seasonal features on Mars. So thanks for any and all classifications you made towards Season 2 and Season 3, and if you have a moment to spare today there’s many more images waiting to be classified at


Tiles and Full Frame Images

I thought I’d go into a bit more into detail about what exactly you’re seeing when you review and classify an image on Planet Four.  On the main classification site we show you images from the HIRISE camera, the highest resolution camera ever sent to another planet.  Looking down from the Mars Reconnaissance Orbiter, HiRISE is extremely powerful. It can resolve down to the size of a small card table on the surface of Mars. The camera is a push-broom style where it uses the motion of the spacecraft it is hitching a ride on to take the image. During the HiRISE exposure,  MRO moves 3 km/s along in its pole-to-pole orbit , which creates the length of the image such that you get long skinny image in the direction of MRO’s orbit. The camera can be tilted to the surface as well, which can enable stereo imaging.

The HiRISE images are too big to show the full high resolution version in a web browser at full size. The classification interface wouldn’t quickly load, as these files are  on the order of ~300 Mb! – way too big to email.  But the other reason is that the full extent of a HiRISE full frame image is too big and zoomed-out for a  human being to review and accurately see all the fan and blotches let alone map them. So to make it easier to see the surface detail and the sizes of the fans and blotches,  we divide the full frame images into bite-sized 840 x 648 pixel subimages that we call tiles.


An example Planet Four Tile

For the Season 2 and Season 3 monitoring campaign, a typical HiRISE image is associated with 36-635 tiles When you classify on the site, you’re mapping the fans and blotches in a tile. Each tile is reviewed by 30 or more independent volunteers, and we combine the classifications to identify the seasonal fans and blotches. To give some scale, for typical configurations of the HiRISE camera, a tile is approximately 321.4 m long and 416.6 m wide. The tiles are constructed so that that they overlap with their neighbors. A tile shares 100 pixels overlap in width and height with the right and bottom neighboring tiles.  This makes sure we don’t miss anything in the seams between tiles .

If you ever want to see the full frame HiRISE image for a tile you classified, favorited, or just stumbled upon on  Talk, there’s an easy way to do it. On the Talk page for each tile we have a link below the image called ‘View HiRISE image’ which will take you to the HiRISE team public webpage for the observation, which includes links to the full frame image we use to make tiles plus more (note= we use the color non-map projected image on Planet Four). Try out this example on Talk.

So next time you classify an image and recall how detailed it is, remember that although it’s just a small portion  of the observation, your classifications are hugely important. Without them we wouldn’t be able to study and understand everything that’s happening in the HiRISE observations. It’s only with the time and energy of the Planet Four volunteer community that we are able to map at such small scales and  individually identify the fans and blotches., which is crucial for the project’s science goals. So thank you for clicks!