Hurricane Maria Mapping Project: We Need Your Help

10-11-2017 06:29 AM
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Esri Regular Contributor
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Hurricane Maria was the strongest hurricane to make landfall in Puerto Rico since 1928. Originating from a tropical wave that the US National Hurricane Center began monitoring on September 13, Maria developed into a tropical storm on September 16 east of the Lesser Antilles. In conditions remarkably favorable for further development, on September 18, Maria underwent explosive intensification, doubling its sustained wind speed to 260km/h (160 mph), becoming a Category 5 hurricane.

As of October 4, the hurricane has caused no less than 79 deaths. Puerto Rico has suffered catastrophic damage. Total losses from the hurricane are estimated between $15.9 and $95 billion. The entirety of Puerto Rico has been declared a Federal Disaster Zone.

Maps and GIS were used to monitor the development of the hurricane and to coordinate initial rescue efforts. GIS continues to be used to assess damage and help with recovery efforts. In the next two images for example, maps illustrate the effect of the hurricane on the electrical grid. The first map shows an average summer night in Puerto Rico, with the electricity grid working in normal conditions. The second map shows what the activity looked like on September 24 immediately after the hurricane when most of the electricity grid was out of service.

This is one of the many ways geography and maps can be used to help Puerto Rico recover. We propose an activity for students to learn a practical use of GIS technology for emergency recovery operations. This will be a fun yet didactic exercise. 

Using high resolution imagery donated by Vexcel Corporation, students will use ArcGIS tools to identify and assess damaged buildings in Puerto Rico. Working as a team, damage across the entire island can be mapped!

Assessing Building Damage Using High Resolution Imagery

This imagery was captured right after the hurricane, which makes it easy to identify damage.  For clarity, proper damage assessments need to be validated on the ground, but the initial interpretation from imagery is a great step to get an initial approximation to the severity of damage.

Here are some examples to illustrate what you can expect. We have a pair of images, one before the hurricane, and one right after it. A small red dot has been added on top of the building indicating that it was completely destroyed.

The next set focuses on an area near the coast. Note that some building have been flagged in green, indicating that no damage has been observed, whereas others are flagged in orange (damage observed) or red (completely destroyed).

Properly identifying damage takes some practice but can be effectively done through careful observation, common sense, and lots of patience.

Do You Want to Try?

Esri has setup all the aerial imagery required to perform damage inspections in Puerto Rico as shown above. We also have setup a powerful web application that will let students easily compare images pre- and post-hurricane as well as tools to flag buildings.

  1. Watch this short video to see and understand the process in operation.
  2. To participate, you will need to join our ArcGIS Online Maria Damage Assessment Exercise Group. Click the link and join the group using your ArcGIS Online Organization credentials. (If your school or youth club does not have an Org account, you can request one.) We recommend that all people in a school or club share a single credential that clearly identifies your group (e.g. "IL_Ourtown_LincolnHS" or "TX_Ourcounty_4Hmappers"), so you and others can look at your team's collective work.
  3. Once you access the ArcGIS Online Maria Damage Exercise group, open the Damage Assessment Application and start mapping.
    1. Navigate the map to find an area where you want to start working.
    2. Engage the swipe tool (upper left) and use it to compare the images before and after the hurricane.
    3. Engage the edit tool (at left) and use the Green, Orange, and Red tools to flag buildings as appropriate. Emphasize accuracy, not speed.
  4. To see all points contributed across all teams, open the General Dashboard (improved version allows viewing by contributor).
  5. [[Added Oct.18]] Please see also the Oct.18 Update, which provides examples and feedback.
  6. [[Added Nov.13]] Please see also the Nov.13 Blog, which provides important context and results

What is next?

The most important aspect of this exercise is to learn and have fun, but you should know that your contributions have a meaning beyond your own. We at Esri are also learning through this entire process with the intent of enabling similar activities in the future.  Thanks for your participation.

[[Note: This document was updated Oct.18 and Nov.13 to clarify the project's purpose and provide links to subsequent write-ups.]]

New Contributor

This is great. But I can't join the group with a public account?!

I am teaching an Intro to GIS class at Radford University. All our students have public accounts. 

Can we not participate?

New Contributor

I see where we could request a free ArcGIS for Schools Bundle - but that appears to be for only K12 schools, not universities. I guess we are constrained by the contract that our University has?

This is a perfect opportunity for our students to apply what they are learning and we'd love for them to be able to help.

New Contributor

I ran into the same problem.  I was unable to join with my personal/public account, but when I signed in through an organizational account it let me join.  Apparently this mapping effort isn't open to everyone?

Esri Regular Contributor

The ArcGIS Online Group noted above is based in an ArcGIS Online Organization. Any Org-based login is able to join. We encourage educational institutions and groups to take this on as a team, identifying your geography/host institution

New Contributor

Hello all - I found in working with my students that some of the buildings have been marked RED (completely destroyed) are actually fine.  Be careful if the building roof is reflective white.  On the reverse, it could be that debris is on the roof and that changes the color.  This is a difference in satellite vs airplane photos and time of day (reflection of sun).  Plus, please remember that the hurricane winds ravaged the trees and so houses may be exposed differently with less shadows.  We have also discovered "blue roofs" showing up - most likely those are tarps which means that the building is damaged but not destroyed.  That said - enjoy!  My students are learning so much.

New Contributor II

I have used an organizational account to log in, but cannot "engage" the swipe tool... don't see it? Any hints? 

Engage the swipe tool (upper left) and use it to compare the images before and after the hurricane.

Esri Regular Contributor

Aloha Annika, After joining the group, go into the Maria group after logging in and you should find the swipe tool. You may need to refresh your browser to see it, and in rare instances maybe even blow out the cache in your browser (which is a good thing to do anyway if using a lot of web apps).

New Contributor III

This sounds great. I am on the ground in PR supporting assessments for public facilities. We keep encountering either FEMA not wanting to share 'FOUO' data, which we are developing a workaround for, or data that just don't exist.

If anybody who sees this is either on the ground in PR collecting, creating, curating, controlling access to data, anything, please let me know so maybe we can meet up to discuss any potential data sharing, tips, tricks, etc. for getting hands on data.

Good luck and be safe if your in PR,


Esri Regular Contributor

20171103, 0800 EDT: Wow, almost 70,000! Tremendous! What is also interesting is seeing how individual teams have worked. By going to the "Results Dashboard" ( and clicking the little blue checkboxes in the middle of the top bar of the "Contributors" panel, you can turn off (or turn on) all the contributions, and then scroll down and find your own. Fascinating and inspiring to see such dedication. Thank you so much for participating!

New Contributor

Dear Charlie:  Greetings. You need to view my comments about the interpretive errors on the damaged buildings published with the tool. There are many, many, many, buildings shown as destroyed when they are in good shape. I know since I am from PR and have been reviewing the FEMA aerial photos to assist in the remediation activities as a volunteer.  The tool should be removed until this problem is fixed, since it is misleading.

Esri Frequent Contributor

Hi Ferdinand. Thanks for your feedback I will make changes in the metadata of the Damage Interpretation Layer to make sure potential users understand that the data has not been curated and it is the product of a crowd-sourcing exercise involving students, and that no systematic QA/QC effort has been enforced on the data . I will apply a similar disclaimer to the tool itself.  Thanks.

New Contributor

Hi, Ismael. I had not seen your response above until today. Although I

appreciate the proposed clarifications, you still leave a defective product

in the public domain. The correct thing to do is to remove the map and try

to fix it. The errors are in the hundreds, and by leaving it published with

a disclaimer is like placing a bandaid on a 10-inch deep wound. There will

be folks that will use the map as is regardless of the disclaimer.

Scientists cannot follow an approach of disclaimers, because we are

supposed to publish curated and verified facts. Again, I strongly recommend

to remove it until it is fixed. Thanks.

About the Author
** Esri Education Mgr, 1992-today ** Esri T3G staff, 2009-present ** Social Studies teacher, grades 7-12, 1977-1992 (St. Paul, MN) ** NCGE Distinguished Teacher Award 1991, George J Miller Award 2016 ** ** ** ** Only education can save the world.