Tag Archives: SBTF

Analyzing Satellite Imagery of the Somali Crisis Using Crowdsourcing

 Update: results of satellite imagery analysis available here.

You gotta love Twitter. Just two hours after I tweeted the above—in reference to this project—a colleague of mine from the UN who just got back from the Horn of Africa called me up: “Saw your tweet, what’s going on?” The last thing I wanted to was talk about the über frustrating day I’d just had. So he said, “Hey, listen, I’ve got an idea.” He reminded me of this blog post I had written a year ago on “Crowdsourcing the Analysis of Satellite for Disaster Response” and said, “Why not try this for Somalia? We could definitely use that kind of information.” I quickly forgot about my frustrating day.

Here’s the plan. He talks to UNOSAT and Google about acquiring high-resolution satellite imagery for those geographic areas for which they need more information on. A colleague of mine in San Diego just launched his own company to develop mechanical turk & micro tasking solutions for disaster response. He takes this satellite imagery and cuts it into say 50×50 kilometers square images for micro-tasking purposes.

We then develop a web-based interface where volunteers from the Standby Volunteer Task Force (SBTF) sign in and get one high resolution 50×50 km image displayed to them at a time. For each image, they answer the question: “Are there any human shelters discernible in this picture? [Yes/No].” If yes, what would you approximate the population of that shelter to be? [1-20; 21-50; 50-100; 100+].” Additional questions could be added. Note that we’d provide them with guidelines on how to identify human shelters and estimate population figures.

No shelters discernible in this image

Each 50×50 image would get rated by at least 3 volunteers for data triangulation and quality assurance purposes. That is, if 3 volunteers each tag an image as depicting a shelter (or more than one shelter) and each of the 3 volunteers approximate the same population range, then that image would get automatically pushed to an Ushahidi map, automatically turned into a geo-tagged incident report and automatically categorized by the population estimate. One could then filter by population range on the Ushahidi map and click on those reports to see the actual image.

If satellite imagery licensing is an issue, then said images need not be pushed to the Ushahidi map. Only the report including the location of where a shelter has been spotted would be mapped along with the associated population estimate. The satellite imagery would never be released in full, only small bits and pieces of that imagery would be shared with a trusted network of SBTF volunteers. In other words, the 50×50 images could not be reconstituted and patched together because volunteers would not get contiguous 50×50 images. Moreover, volunteers would sign a code of conduct whereby they pledge not to share any of the imagery with anyone else. Because we track which volunteers see which 50×50 images, we could easily trace any leaked 50×50 image back to the volunteer responsible.

Note that for security reasons, we could make the Ushahidi map password protected and have a public version of the map with very limited spatial resolution so that the location of individual shelters would not be discernible.

I’d love to get feedback on this idea from iRevolution readers, so if you have thoughts (including constructive criticisms), please do share in the comments section below.

Passing the I’m-Not-Gaddafi Test: Authenticating Identity During Crisis Mapping Operations

I’ve found myself telling this story so often in response to various questions that it really should be a blog post. The story begins with the launch of the Libya Crisis Map a few months ago at the request of the UN. After the first 10 days of deploying the live map, the UN asked us to continue for another two weeks. When I write “us” here, I mean the Standby Volunteer Task Force (SBTF), which is designed for short-term rapid crisis mapping support, not long term deploy-ments. So we needed to recruit additional volunteers to continue mapping the Libya crisis. And this is where the I’m-not-Gaddafi test comes in.

To do our live crisis mapping work, SBTF volunteers generally need password access to whatever mapping platform we happen to be using. This has typically been the Ushahidi platform. Giving out passwords to several dozen volunteers in almost as many countries requires trust. Password access means one could start sabotaging the platform, e.g., deleting reports, creating fake ones, etc. So when we began recruiting 200+ new volunteers to sustain our crisis mapping efforts in Libya, we needed a way to vet these new recruits, particularly since we were dealing with a political conflict. So we set up an I’m-not-Gaddafi test by using this Google Form:

So we placed the burden of proof on our (very patient) volunteers. Here’s a quick summary of the key items we used in our “grading” to authenticate volunteers’ identity:

Email address: Professional or academic email addresses were preferred and received a more favorable “score”.

Twitter handle: The great thing about Twitter is you can read through weeks’ worth of someone’s Twitter stream. I personally used this feature several times to determine whether any political tweets revealed a pro-Gaddafi attitude.

Facebook page: Given that posing as someone else or a fictitious person on Facebook violates their terms of service, having the link to an applicant’s Facebook page was considered a plus.

LinkedIn profile: This was a particularly useful piece of evidence given that the majority of people on LinkedIn are professionals.

Personal/Professional blog or website: This was also a great to way to authenticate an individual’s identity. We also encouraged applicants to share links to anything they had published which was available online.

For every application, we had two or more of us from the core team go through the responses. In order to sign off a new volunteer as vetted, two people had to write down “Yes” with their name. We would give priority to the most complete applications. I would say that 80% of the 200+ applications we received were able to be signed off on without requiring additional information. We did follow ups via email for the remaining 20%, the majority of whom provided us with extra info that enabled us to validate their identity. One individual even sent us a copy of his official ID. There may have been a handful who didn’t reply to our requests for additional information.

This entire vetting process appears to have worked, but it was extremely laborious and time-consuming. I personally spent hours and hours going through more than 100 applications. We definitely need to come up with a different system in the future. So I’ve been exploring some possible solutions—such as social authentication—with a number of groups and I hope to provide an update next month which will make all our lives a lot easier, not to mention give us more dedicated mapping time. There’s also the need to improve the Ushahidi platform to make it more like Wikipedia, i.e., where contributions can be tracked and logged. I think combining both approaches—identity authentication and tracking—may be the way to go.