A Brief Overview for Building Your Own Crowdsourced Map to Fight the Transmission of Contagious Diseases 

Tina Whitfield, Director, Digitalglobe


In 2015, contagious diseases are first-world problems and every-world problems.  In the United States, tuberculosis, whooping cough, HIV, HPV, West Nile virus, and influenza lead new cases.

The United States has also seen a rise in contagious meningitis. Contributing to the meningitis spread was an incomplete picture of where the affected populations were and how the disease was being transmitted. Communities wanted more data than the Centers for Disease Control and Prevention was able to provide.  They wanted to crowdsource their experiences and insights, then explore, analyze, map and understand the information, but did not know where or how to begin.

Analyzing images, understanding remote locations, and mapping the planet are challenges that are no longer limited to scientists and experts. Now anyone who can write code or use a smart phone can become a human geographer.
— DigitalGlobe

The remainder of this article addresses this need – crowdsourcing experiences and lessons learned.  We will look at how communities can actively develop organic, local solutions to control and perhaps eradicate the spread of contagious diseases.

Third-World Control and Eradication

Stopping transmission everywhere includes learning how third-world countries are controlling and eradicating contagious diseases.  What tools are they using and how are they using them?


According to the World Health Organization, communicable diseases were responsible for 32% of disease-related deaths in 2012.  They found that disease transmission increased in low-GDP countries such as Afghanistan, Cameroon, Equatorial Guinea, Ethiopia, Iraq, Israel, Nigeria, Pakistan, Somalia, and Syria because of lack of resources for prevention, control and eradication. 

Crowd Sourcing with Satellite Imagery to Eradicate Polio

When we analyze satellite imagery, we see the destructive impact that contagious diseases have in the third world.  But, when we analyze satellite imagery that has been coupled with crowdsourcing solutions to eradicate disease, we see a better world.  According to Rhiannan Price, Product Marketing Manager at DigitalGlobe, "the combination of imagery and crowdsourcing means unlocking critical information from terabytes of data."  

High resolution imagery and crowd sourcing help identify remote villages.

High resolution imagery and crowd sourcing help identify remote villages.

For example, the DigitalGlobe image above is a map of human settlements in a remote village in Kano State in Nigeria.  A global community of online volunteers scoured DigitalGlobe’s high resolution Basemap +Vivid imagery looking for remote communities like this village in Kano State.  When villages were found, their locations were mapped.  So rich was the process, the volunteers identified villages that neighboring communities did not know existed.

Healthcare Workers

Identifying these remote villages allowed health workers to reach everyone in their polio vaccination campaign.  Said Price, “Basemap +Vivid uses a deep historical archive to create comprehensive mosaics to provide a consistent view of areas of interest so that remote locations are equally visible to those that are well documented.”

Polio Today

While most of the world has eradicated polio, in Nigeria, Somalia, Pakistan and Afghanistan, the number of polio infections has actually grown in the 21st century. The Centers for Disease Control and Prevention describes polio as a disease caused by a virus that affects the nervous system and is mainly spread by person-to-person contact, though it can be spread through drinking water or eating raw and undercooked food contaminated with the feces of an infected person.

Waterways can be natural barriers for disease transmission… unless they have a major highway crossing. 

Waterways can be natural barriers for disease transmission… unless they have a major highway crossing. 

In 2014, DigitalGlobe joined some of the world’s largest development organizations in the fight to eradicate polio.  Today, both Somalia and Nigeria have achieved more than a year without polio infection.  Let us look at the tools DigitalGlobe brought to fight.


Immunizing communities along transmission routes where people previously weren’t adequately vaccinated reduced the transmission of the polio virus.  However, before DigitalGlobe’s involvement, health care workers were challenged in their ability to provide immunization because most of the transmission routes and settlements where polio thrived were unknown and unmapped. 

Geospatial Big Data Algorithms

DigitalGlobe brought to the polio eradication effort its crowdsourcing solution team that used DigitalGlobe remote sensing technology and big data analytics engines with settlement identification data from Tomnod volunteers.  The result: the team was able to provide health workers the location of remote settlements, number of doses needed for each area, and data that enabled the health care workers to determine how to best allocate limited human resources.

Price underscores the importance of the human-to-machine interface:  “When big data analytics is combined with crowdsourcing, solutions to information gaps challenging health can be solved, and we can control and eradicate contagious diseases.”

Tomnod, the Tool of All Crowdsourcing Tools

What is Tomnod?  And, why is it important for developers to understand before building their own crowdsourcing application?

Tomnod is more than a tool.  It is a web-connected global community of volunteers that identifies and tags important objects and interesting places in satellite images provided by DigitalGlobe. In the fight against polio, DigitalGlobe technologists tasked an analytics engine using machine learning algorithms to evaluate terabytes of data and identify all areas of human habitation.

Dr. Luke Barrington, Senior Director of Technology Products for DigitalGlobe, explained how crowdsourcing technology and Tomnod were used to stop the spread of polio.  “DigitalGlobe’s massive image library covers the entire planet many times over in amazing high resolution,” Barrington said. “It’s a huge challenge just figuring out where in the world to look. We start by using algorithms to narrow down the search space and identify locations in the images that look like human settlements. But computers make mistakes – that’s where the crowd comes in.”

“Tomnod volunteers worldwide confirmed whether or not each image actually contained a building. More than 45,000 volunteers helped validate the village detection results across Nigeria, Somalia, Afghanistan and Pakistan. For Somalia, the volunteer-driven campaign lasted three days and covered over 120,000 polygons. The end result was a map of 285,103 settlements, many of those remote and not known to regional healthcare workers.”


Human Geography Data

What is human geography and why is it important in the fight against the spread of contagious diseases?

Oktoberfest in Munich, Germany.  Large gatherings can enhance the transmission of contagious diseases. 

Oktoberfest in Munich, Germany.  Large gatherings can enhance the transmission of contagious diseases. 

Penn State University describes human geography as patterns and processes that shape human interaction with the built and natural environments.  So how are patterns and processes that shape human interaction with man-made and natural environments important to the identification and eradication of contagious diseases? To understand the importance of this in the context of mapping we turn to Dr. Barrington’s work developing human geography data layers for maps and to explain the relevance of these data layers for DigitalGlobe efforts to help combat Ebola in West Africa.

“While satellite imagery contains a rich depth of information, extracting that information can be time consuming and expensive. We use our experts and algorithms to analyze the imagery and create maps that make it quick and easy to make decisions and take action. Maps built from these information layers enable timely and targeted transport of vaccines by identifying road obstructions, detecting urban changes due to man-made activity or natural disasters, marking landing zones where supplies can be flown in and people can be evacuated out, and locating relief clinics.”

DigitalGlobe human geography data layers contain information about the environment, location of infrastructure, demographics of a region including economies, ethnicities, and education levels, to name a few.  More detailed data include life-saving facilities such as hospitals and evacuations centers, settlements, roads, and ports where disease has the greatest risk of transmission and populations are most at risk.


When you combine crowdsourced data, automated analytics, human geography data, and a mapping API with Earth imagery, the output is powerful and productive.

Types of crowdsourced content that can be integrated into apps you build include:

Content                   App Example

Weather news          Moji

City Guides              Kamino

Driving                     Waze

Transit                     Moovit

News                       Grasswire


Where to start

One of the easiest ways to get started learning how to map is by contributing to OpenStreetMap (OSM). Like Wikipedia for geographic data, OSM invites anyone in the world to add to or edit the global map by uploading local knowledge or GPS info, or by tracing locations from DigitalGlobe satellite imagery.

For developers, online mapping APIs provide all the basics needed to get up-and-running easily and cheaply while still having access to robust tools for extensive customization as the users develop their skills. Examples include Google Maps API, Bing Maps API, Mapbox and DigitalGlobe Maps API.

DigitalGlobe Maps API

The DigitalGlobe Maps API offers geospatial data layers critical to mapping anywhere in the world including access to the world’s highest resolution satellite imagery as well as global maps of roads, buildings, and points-of-interest from OpenStreetMap. For example, OpenStreetMap allows map developers to leverage the power of crowdsourcing and assist with the identification and classification of features such as villages and roads in remote areas that have not been previously mapped. Since all data contributed to OpenStreetMap becomes available to any systems that subscribe to it, crowdsourced data is generally integrated back to the community within hours.

Remote terrain in Alberta, Canada.

Remote terrain in Alberta, Canada.

“DigitalGlobe Maps API makes it easy for developers to plug the world’s most beautiful and complete satellite imagery straight into their mapping apps. Now you can explore anywhere in the world and engage a global user base to extract valuable geospatial information. This is the API we needed to build our own crowdsourcing applications – now we’re sharing it with the world!” said Luke Barrington.


Consider your crowd as beta testers.  Ensure there is stability across devices before launching the beta test.  And, ensure your team can easily support the user experience intended for the crowd. Include ways that testers can offer feedback and bug reports through cloud-based tracking systems such as Github. Also, make sure that you have captured your beta testers email addresses and plan on sending them regular updates on the progress of your beta.

Crowds Eager to Test

BayGeo:  formerly known as the Bay Area Automated Mapping Association (BAAMA), leads, mobilizes, and engages users of geospatial technology and map enthusiasts in the San Francisco Bay Area.

FOSS4G: Free and Open Source Software for Geospatial organizes events for contributors, adopters, users, extenders, teachers, service providers, consumers and business and research organizations to share their expertise and learn from each other. 

Maptime: an open learning environment for mappers of all levels and degrees of knowledge, offering intentional educational support for the beginner.  Maptime chapters host mapping tutorials, workshops, ongoing projects with a shared goal, and independent/collaborative work time.

OpenStreetMap: the community is diverse, passionate, and growing every day. The contributors include enthusiast mappers, GIS professionals, engineers running the OSM servers, humanitarians mapping disaster-affected areas, and many more.


Analyzing images, understanding remote locations, and mapping the planet are challenges that are no longer limited to scientists and experts. Now anyone who can write code or use a smart phone can become a human geographer. DigitalGlobe is empowering this new generation of mobile mappers by making it easy to access the world’s largest library of commercial high-resolution satellite imagery. DigitalGlobe Maps API delivers amazing satellite images and up-to-date map layers over a simple API that plugs into your web or mobile app. Whether you want to help eradicate disease, locate remote populations, or just find a better way to get where you’re going, try out the free beta of DigitalGlobe Maps API at

More on Tomnod can be found here:

Fall 2015 Volume 8 Issue 2