Friday 1 September 2017

Emergency response maps as easy as 1-2-3

Update 5: read here my  new occupation inspired by this 18 months later
Update 4: for a predictive app using Esri & Alexa, see this example in Maryland
Update 3: presented at European Petroleum GIS Conference in London, 2 Nov 2017
Update 2: Medium professional channel posting on Open Data issues raised here
Update 1: Youtube of  freely available data show flood spread from 27 to 30 August

Crowdsourcing for disaster response

That news item illustrates the power of citizen engagement that's built atop the enormous work done already in the open data sphere. Consider the responses from a single request on LinkedIn for flood maps for Houston after Hurricane Harvey:

have u tried
how about 
See if Sentinel-2 captured anything
We also have a DEM available.
Have you checked!/statewide
Try our Voyager Search's ODN (Open Data Network)
Here is another you can try.
you can contact the Esri Disaster Response Program at

My last response after these, at the time of writing, is the map I will explain right now.

1) Open Data

This topic has been well covered, I will only point out the best catalogue I ever found, by Robin Wilson from University of Southampton. I have also tracked the same via and twitter feeds. A few years ago I helped correct the map front-end for, and I recently joined "the social network for data people".

That alerted my to for environmental risk data, especially the flood modelling specialists from University of Bristol. Flooding has been a hot topic worldwide, and rainfall runoff and catchment basin modelling is not a simple topic, so varied are the factors involved.

2) Emergency

The Hurricane Harvey pathway was well documented in the mapping, environment and general media. Devastation at its landfall in Rockport TX paled in comparison to the 52 in. / 1.3 m. rainfall on 26 August, a record since data were kept. Judging by previous tropical storms & hurricanes, subsequent rainfall & flooding would create real damage.

Oasis has a comprehensive catalogue, and some data is free for personal or disaster relief use, where "non commercial" is the name of the game. Once permission was granted, it was a matter of accessing the proper Web Mapping Service (WMS). Not only have I used ArcGIS Online since its inception, but it also has a treasure-trove of data, as for example 3 out of the 8 in the quip at top.

Hurricane Harvey OasisHub
This map shows in meters depth the flooded areas, modelled for 72 h. leading up to 27 August. Data are released daily and added to this web map as they are released. In my old neighbourhood near Addicks & Barker Reservoirs, catchment basins for water flowing from central Texas to the Gulf of Mexico, you can see that its barriers were breached at top and left (N & W), that the Buffalo Bayou broke its banks, but that street flooding was not severe yet. Remember we're a couple days behind in posting processed data.


3) Social Media

News then came via Facebook that an facility in NE Houston was in danger of exploding:

A Twitter feed alerted me that @spangrud had already posted a hazard map of that area:

Voila! Conflate the Oasis with Damian's maps and you get the map linked above...

But it doesn't stop there! A local resident re-tweeted my posting of that map, to alert their neighbourhood...
Luckily mobile / cell phone coverage survives localised power cuts, and twitter works well on lower bandwidth phone coverage.

This followed a flurry of local resident tweets, one quoting the local Fire Marshall:

This is not trivial: evacuation orders are often hard to grasp by residents, whose immediate concerns often mask  the bigger picture where danger may come from. This exemplifies, therefore,  how social media and accessible mapping interact for the better good.

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