SOCIETY | Oct 23, 2018

Data and OpenStreetMap for mitigating environmental risk

From earthquakes to small everyday emergencies, the role of the world's largest database of free geographical data

Italy is a country with little memory. We read this from time to time in newspapers shortly after major calamitous events. Italians are excellent in times of emergency, but after that they forget the everyday. An everyday made of prevention, of major works but also of small and no less important works.

An acronym practically unknown to most in Italy is DRR which stands for Disaster Risk Reduction, or that series of actions (or systematic approach, according to Wikipedia) that aim to identify, quantify and reduce the risk of disasters. The first part of this process is therefore the gathering of information.

If the source of potential disasters is clear enough, the origin often lies in a series of contemporaneous causes or events. If only some of the possible triggers are assessed in the risk scenario, perhaps due to the ignorance of the existence of some of them, the assessment may be distorted and underestimated or not even taken into consideration.

Data and Disaster Risk Reduction

Generally speaking, the data for analyzing similar scenarios are many, of different categories, from multiple sources, and with different data formats (and often with user licenses that are not compatible with each other). It should be added that sometimes there is also the difficulty of finding the data published on who knows which site.

After this first phase there is analysis, the actions to be taken to reduce the risk and, no less important, communication and sensitization of the population. But we will focus here on the collection of information in particular.

Why OpenStreetMap?

OpenStreetMap (OSM), a project based on crowdsourcing that feeds the world’s largest database of free geographical data – which has been in existence for more than 14 years – is now a reality that should never be overlooked when talking about spatial information.

We are talking about databases before maps, because OpenStreetMap allows anyone, free of charge, to download small portions (or even the whole world) of its database; this in multiple formats depending on the technical knowledge of the user.

Which data in OpenStreetMap are useful in the field of environmental risk?

Very many, also because events have repercussions and side effects. On OSM you can find industrial settlements, hydrographic graphs, roads and pathways, weight and shape limits on roads and bridges and in tunnels, power lines, schools, hospitals and shelters for the elderly, but also helicopter pads, sports fields and areas for emergency takeoffs or for stacking areas, etc.

And all with global coverage, in the same geographical projection and available 24 hours a day, 365 days a year. Think of the 2016 earthquakes in central Italy that hit 4 regions: at the least there were 4 Regional Technical Cards (CTR) to “pin up”, just for the basic information layers. And in the event of an event covering different states it is even worse.

In addition to major risks, OpenStreetMap is also useful for small everyday emergencies. In fact, it is possible to enter or search for defibrillators, hydrants or house numbers (useful for the emergency phone number and the firefighters). And apps that use OSM data are increasingly on the smartphones of rescue workers or the GPS of Mountain Rescue.

Reliable data?

The first question that is asked is about the validation/reliability of the data. But if 98% of the data comes from individual contributors, what reliability do I have? Is the system not at the mercy of vandals?

Several studies claim that the overall quality of the data is generally good. Obviously neither the coverage nor the quality is not heterogeneous, but there are many systems for monitoring activities and quality control. In addition, larger or smaller companies that generate business with OSM data have in-house teams that perform the same activities as voluntary mappers. And we are talking about companies like Mapbox but also Facebook, Microsoft or Apple (all present with their presentations at the recent “State of the Map 2018”  world conference of the OSM community, held in July at the Politecnico di Milano).

The OSM database is also extremely robust. Based on a PostgreSQL DB with PostGIS extensions and replicated in different areas of the planet, it keeps the history of all objects allowing a quick rollback of objects or entire sets of uploads (called changesets).

The advantages are noteworthy. The speed of database updating is in real time. The numerous apps and editing software allow interaction at different levels of complexity, passing from professional GIS systems to apps with gamification mechanisms, such as StreetComplete.

The detail with which an object can be described is remarkable. In some cases, to obtain the same information on an object via CTR or Topographic DB it is necessary to cross-reference at least another couple of dabatases.

Example of ownership of a road arch

The worldwide developer community makes available – almost always open source and free of charge – a plethora of tools for handling, filtering or utilizing OSM data. The same data are available for download in different formats, from the native XML format to Shapefile or the recent Geopackage.

A couple of sites for downloads are Geofabrik and the service of Wikimedia Italia which updates the extracts of individual regions and municipalities on a daily basis for Italy.

In the case of preventive mapping campaigns or post-event interventions, there are volunteer coordination tools that divide the intervention area into small boxes and that allows the automatic display in overlay of satellite images after the event, as soon as they are available.

In the following image a demo exercise held in early October at a meeting in Brussels for the V-IOLA project on the subject of Disaster Risk Reduction and Capacity Building in which Wikimedia Italia participated together with the Department of Civil Protection, Italian Red Cross, ANPAS, CISOM and other foreign partners.

The Tasking Manager used to coordinate the activity of many mappers

To enter the OSM universe there are some documental resources and numerous tutorials and video guides. The first step is to have clear the limits and possibilities dictated by the use licenses. Who wants to contribute to the project can start from the step by step guide or enter the wiki (complete but a little dispersive). Those interested in business use will find interesting information here.

For more information, contact Wikimedia Italia, the Italian chapter of the OpenStreetMap Foundation.

OpenStreetMap is a decidedly bottom-up approach to geographic information. You can still pretend that this reality does not exist or start to understand what benefits it can bring. Certainly, in this increasingly complex world, we cannot go on thinking “but it has always been done like that”.

Alessandro Palmas