Azavea Atlas

Maps, geography and the web

Balloon Mapping: A Citizen Science Exercise

Philly Tech Week, now in its fourth year, brought numerous creative and inspirational events to Philadelphia. GeoPhilly, Philadelphia’s meetup for spatial and mapping enthusiasts, hosted a fun, educational event during the festival. Balloon mapping is a DIY and affordable technique for capturing high resolution aerial imagery and it puts the power of data collection in the hands of the data consumers.

This approach can be particularly helpful in times of disaster or urgency when it is too costly to capture imagery in traditional ways (satellite and low flying aircrafts).  You can learn more about these methods in my 2013 blog on mapping techniques during emergencies and the Public Labs page about balloon mapping during the 2010 Deep Horizon Oil spill.  Balloon mapping can also be used during gatherings, community events or protests to photograph the crowd such as Occupy Wall Street. Or it can be used for the mapping of public space such as the Benjamin Franklin Parkway in Philadelphia.BalloonImage1

Engaging the Community

Balloon mapping is an easy way to engage the community by inviting participants to learn the methods and conduct their own balloon mapping exercise.  The unique  thing about balloon mapping, compared to drone mapping, is that it is very transparent: a large red balloon tethered to a person clearly shows that the mapping process is public and not hidden or secretive.  This was evident at our balloon mapping event which had numerous passersby comment and inquire about the exercise. In this way, it engages community members and neighbors in the activity.

How does balloon mapping work?

A 5ft diameter balloon is filled with helium (a 80CU tank is sufficient for one balloon) and attached to approximately 1000 ft of cord which is tethered to a moor (either a very heavy object or a person). The balloon has a camera rig attached to the base which holds the camera steady. The camera is programmed to automatically snap photos at regular intervals. The balloon is raised in the air, though always tethered, and continuously collects high resolution photographs of the area. Kite or pole mapping can also be used to capture photos from above. The photos are later downloaded and stitched together using reference images and open source software MapKnitter.

Aerial image captured from camera on ballonThe images captured by our balloon mapping exercise are free for anyone to access and enjoy. You can find all the photos taken during GeoPhilly Balloon Mapping on google drive, along with instructions, a video and other resources.

You can still get involved, even if you don’t organize a balloon mapping activity. The open source software MapKnitter can be used by anyone to stitch together the photos taken at other DIY aerial mapping activities. You can contribute to other projects by helping out with stitching.


Special thank you goes out to the Delaware River Waterfront who allowed us to use their space for this activity. And special thanks to Michelle Schmitt for co-hosting the event and providing ample moral support! Also special thanks to Azavea for funding this event and for all the attendees who participated and helped stitch the photos together.

Azavea at the Do Good Data Conference

Last week, Tyler Dahlberg and I attended the Do Good Data Conference in Chicago, IL. The conference was a two-day extravaganza of workshops and talks geared towards nonprofit data geeks and professionals looking to learn new skills.

One of the sessions I found particularly insightful was hosted by Matthew Scharpnick of Elefint Designs. Matthew offered tips for effective data visualizations and creating infographics. He noted that raw data can deceive and how important context is. One of the case studies he brought up was the on-going debt ceiling debates during in 2012. At the time, there was a hot political debate about which party (and President) was responsible for running up budget deficits and debt. A graph chart of U.S. debt over time is one way to look at this — but there’s more nuance than simply political party in charge or President at the time. There’s even differences depending on whether the data is normalized by GDP, for example.

For example, if you only saw the chart on top left, you might think that U.S. debt is out of control and has never been higher. But if you look at debt as a percentage of GDP, you can see that in fact debt was higher in the 1940s during World Ward II.

So Elefint created an infographic to try to tell multiple stories and show context. Designers chose to symbolize the line by which party controlled the Presidency, House and Senate. Looking at President, it’s natural to infer that in recent times, Republican administrations appear to be more responsible for running up U.S. debt. But when Congress is added, that narrative becomes much more nuanced. Finally, by adding the recession periods to the graph (in gray), it becomes apparent that perhaps debt always increases after a recession, regardless of which party controls the Presidency or Congress.

It’s important to remember that data doesn’t teach us everything and it’s easy to miss the whole picture without the proper context. Matthew also stated the importance of direct labeling and telling a story — but noted that there doesn’t always have to be a linear story to each visualization — each person will see what they want to see. Moreover, he brought up the idea of “Return on Design” and mentioned crafting pieces that can be “productized” and reused.

Tyler and I also presented a session at the conference. We outlined the bike theft and pedestrian crash analysis we worked on at Azavea — offering numerous spatial analysis tips along the way. The workshop portion was devoted to a hands-on demo of QGIS mapping, including the QGIS2Leaf plugin. We also demonstrated web mapping in CartoDB, including setting up infowindows with Google Streetview images and the Torque library for animated heatmaps. We’ve posted the presentation and workshop instructions online and we hope to see everyone next year!

Announcing our 2015 Summer of Maps Fellows and Projects

Summer of Maps offers fellowships to student analysts to perform geographic data analysis for non-profit organizations.  The program matches non-profit organizations that have spatial analysis and visualization needs with talented students of GIS analysis to implement projects over a three-month period during the summer.  We are thrilled to announce the 2015 Summer of Maps fellows and the non-profit organizations they will work with.  Please join me in congratulating:

Kevin Frech, B.A. Candidate, Geography and Urban Studies at Temple University, working with:

Laura Laderman, Major: Physics, Minor: Statistics at Swarthmore College, working with:

Nathaniel Henry, Bachelor of Science in Geographic Information Science and Bachelor of Science in Geography: Urban, Regional, and Global Studies with Minors in Economics, Chinese, working with:

We are very excited to work with our 2015 Summer of Maps fellows and support them through their work with these nonprofits.  Students interested in the 2016 program or non-profits that would like to submit a project, please visit the Get Involved page of our website. 

We are also enormously grateful to the organizations that sponsor the Summer of Maps Program each year. Thank you to our 2015 sponsors:

Esri Logo

Logo for Temple University Professional Science Master's in Geographic Information Systems

Logo for sponsor: Betsy and Jesse Fink

If you’d like to sponsor the 2015 program, we welcome you to find out more information here.

Building TreesCount! 2015

Every day is a great day to celebrate trees, but on the last Friday in April, our hardworking urban forests get the attention they really deserve. Today, on Arbor Day, we’re excited to announce the launch of TreesCount! 2015, the NYC Parks‘ initiative to map and catalogue every street tree in New York City using a web application developed here at Azavea.


NYC Parks has compiled info on every street tree in all five boroughs every ten years since 1995. With more than 600,000 trees to map, this year’s census is no small task. How do you gather vitally important data about that many trees in just a few months while ensuring it’s as accurate as possible? Get tree loving New Yorkers to help! NYC Parks is partnering with civic and neighborhood groups and encouraging members of the public to become “voluntreers” who will join Parks’ staff in counting trees throughout the city.

Azavea’s task was to build the web application that would enable volunteers to learn more about the census, sign up for mapping events, and log data about the trees via smartphones and tablets while also providing NYC Parks with the tools to review data and coordinate mapping activities. The resulting TreesCount! 2015 software is an open source application that includes:

  • A map to view the ongoing progress of the census
  • A training system to provide users with the info they need to accurately gather tree data
  • Group and event pages where volunteers can learn about community organizations and RSVP for tree mapping events
  • A reservation system for checking out block edges for mapping
  • The Treecorder application for entering data about each tree
  • Administrative tools to ensure the census includes trees in all parts of the city and results in accurate data


Volunteers will map the trees using a method developed by TreeKIT, a non-profit group focused on community involvement in urban forestry. Based on centuries’ old surveying techniques, volunteers using the TreeKIT mapping method select a block edge segment and use measuring wheels to accurately log the distance between intersections and trees. Those distances are translated into geographic coordinates that accurately identify the tree’s location. We expanded the initial TreeKIT mapping application into the new Treecorder, a responsive web application that enables volunteers to efficiently and accurately enter tree data via their mobile devices.

The work on TreesCount! 2015 aligns well with Azavea’s other urban forestry related projects, particularly OpenTreeMap (OTM) – the subscription-based platform for collaborative geography-enabled urban tree inventory. OTM encourages the general public to learn more about the trees in their communities by exploring and updating tree data as well as info on green infrastructure features such as rain gardens.

NYC Parks will use the data gathered as part of TreesCount! 2015 to gain a more complete understanding of the current urban forest and plan future street tree plantings, maintenance, and stewardship activities. With an accurate inventory of over 600,000 street trees, NYC Parks can calculate the environmental and economic benefits of the trees and demonstrate why trees truly are worth celebrating every day of the year.

If you’re interested in mapping trees in NYC this summer, visit the TreesCount! 2015 website and sign up to become a trained volunteer, explore the many community groups organizing events, or check out the the mapping progress. Mapping begins May 19!

The Changing Map of the Arctic

When we think of geopolitical conflict quite a few areas come to mind, but one quite significant and often overlooked area is the Arctic. As the landscapes of the northern latitudes transform — most significantly due to climate change — geographers and mappers will have their work cut out for them recording those changes and helping to explain what they mean for the rest of the world.


Former Alaska Lt. Governor Mead Treadwell gave a talk about mapping the landscape of the Arctic at the 2015 Annual Association of American Geographers Conference on Tuesday in Chicago, IL. Treadwell has a long history of involvement with business and environmental interests in Alaska and the Arctic region. Prior to being elected Lt. Governor, he served on the United States Arctic Research Commission and managed the Exxon-Valdez oil spill response for Cordova, Alaska.

Changes in the geography of the Arctic related to climate change will have many profound impacts. For one, oil exploration is sure to increase with less sea ice to contend with. Bathymetric mapping explorations are continuing to cover more of the sea floor as well. As sea ice recedes, shipping channels are opening up, including a link between East Asia and Europe that previously required routing ships through the Panama Canal. These journeys can now be completed more efficiently and throughout a longer portion of each year by re-routing through the Arctic.

Climate change and shifting geography in the Arctic also has implications for the U.S.-Russia relationship. Russia has made it well-known that it would like to expand its territorial claim to the Arctic, and as Treadwell pointed out in his presentation, Russia is much further behind the U.S. in releasing scientific data to the public. Treadwell emphasized the need for a science agreement with Russia so that the data they collect be made available for research. As of late last year, Russia was planning to apply to the United Nations Commission on the Limits of the Continental Shelf to expand its claim on the Arctic by about 463,000 square miles. This great graphic from The New York Times shows the current territorial claims from each nation with a border claim in the Arctic.

Finally, Treadwell emphasized the importance of maintaining place names and languages. There’s an incredible amount of data contained in historic place names. Alaska’s legislature recently made twenty native languages official, granting them parity with English.

Above all else, Treadwell urged geographers and the public at large to pay attention to what takes place in the Arctic, though it might seem far away to those living in the lower 48, it’s extremely important to our future.