Milan - Collaboration between local transit agency and OSM community
Milan's transit agency makes the most of local mapping activists and builds a sustainable solution for the region.
In 2013, Milan's transit agency (AMAT) had to cover a practical need: build an online portal displaying mobility information in the city, but integrated with the rest of the region's system. This required the use of a road network graph, of which AMAT had only Milan's portion. Additional requirements involved a focus on open licensing, data interoperability and ease of maintenance.
A possible solution might have been relying on commercial products, a route that the agency explored in past (using the TeleAtlas graph). But this option would have been:
expensive
difficult to update (i.e. you had to wait for the data provider to actually update the layers)
incompatible with the online portal licensing.
Instead, AMAT opted for syncing its own graph to OSM, thus connecting it to the rest of the regional graph
for free, excluding the labour/maintenance costs which would have been present in the commercial option as well
with complete control over the published data, capacity to updated it etc…
with an open license.
Stakeholders involved
AMAT Their involvement in the project was mainly motivated by the possibility to rely on a larger community of users to keep its data updated and valid (--note: classic example of "bazaar" story "with enough eyeballs all bugs are shallow").
Local OSM community The community had the chance to have the OSM graph equally validated from an official data source, and effectively having the local authority "entering" the community.
Types of data
Original AMAT transit network graph follows roughly the Geographic Data Files (GDF) specs. The data belong to Milan's municipality (not directly to AMAT) and was licensed as CC-BY.
Technical solutions
The project involved ~10 mappers sourced from the local community whose task consisted of editing the OSM graph at the geometry and the tag level, to effectively make the two data structures match. A loc_ref tag was used to map AMAT graph segments onto OSM's.
Custom instance of the HOT Tasking Manager
used to distribute the workload among the mappers
Github to keep tracks of ongoing issues.
JOSM plugin developed specifically to facilitate the mapping operations
Subsequent outcome, success stories
"This project was born out of a very practical and contextual need...OSM let us to retain [ technical] control over our data, while at the same time allowing it be distributed openly and freely"
The synced graph is currently used in production at AMAT and serves as the basis for mobility reports, traffic analysis etc..
The project had an initial cost (hiring the mappers, setting-up the workflow, acquiring knowledge about OSM..) but on the long-term, two years after the official end, it requires just 1 day/week of work for a dedicated technician to keep everything in parallel.
The overall quality of AMAT's road graph greatly improved by incorporating details from OSM. In parallel, OSM network benefited from the revision of AMAT mappers and is now kept updated with an official cartographic source.
The knowledge regarding OSM's ecosystem accumulated during the project serves AMAT technicians in their daily activities.
"Keeping an open and constant engagement with the community was paramount. Some of the adopted conventions (i.e. the loc_ref tag ) were later incorporated in the mapping practices of local community members".
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