Natural Resources Canada-OpenStreetMap Synergy

Interaction type

Government → Public → Government

Trigger Event

The proven inability of the NMA to keep datasets up-to-date along with the familiarisation of its personnel with OSM data, quality and processes.

Domain

Generic Mapping (Update of National topographic database)

Organisation

Mapping Information Branch (MIB) at Natural Resources Canada (NRCan)

Actors

OSM Community, MIB, NRCan.

Data sets in use

Canvec (mainly the road network)

Process

NRCan releases its database into .osm format. The data is imported into OSM database and updated/modified by the OSM community. NRCan regularly compares OSM datasets with its own database as an change detection mechanism so to keep up-to-date its database

Feedback

Change detection datasets that were verified in the field by NMA’s employees.

Goal

Keep the national databases up-to-date.

Side effects

OSM data cannot directly be used by the authorities due to IPRs and licensing issues.

Contact Point

The main duty of National Mapping Agencies (NMAs) is to provide up-to-date topographic maps and a range of spatial products to public and private sector. Likewise, the role of Mapping Information Branch (MIB) at Natural Resources Canada (NRCan) is to provide accurate geographic information of landmass at the scale of 1:50.000. However, this task is translated into regularly covering an area of 10 million Km2 divided into 13,200 map sheets. In this context, keeping geographic information up-to-date is a challenge and there is an open question if and how the updating process can profit from the evolution of VGI.

Taking into account the results of ongoing research regarding VGI quality, Canadian authorities choose to co-operate with the OSM community. As Beaulieu et al. 2009 describe (Figure 1.1), the first step to this synergy was made by the Centre for Topographic Information in Sherbrooke (CTIS) which released the Canvec product (digital topographic map of Canada) in .osm format (the native OpenStreetMap format). This move further enabled the integration of the Canadian authoritative data into OSM and gave the chance to the OSM community to interact (i.e. complete, correct or update) the authoritative data. The next step is to regularly compare the OSM database with the Canvec data so to pinpoint the differences (Figure 1.2). Those differences are treated as potential changes and are verified using the authoritative channel at the field. Verified changes are propagated to the Canvec database.

Figure 1.1 The loop of synergy OSM-Canadian authorities. (source: Beaulieu et al. 2009)

Figure 1.2 Change detection using OSM. Gray: OSM road network, green: data missing from OSM, red: data missing from authoritative data. (source: Beaulieu et al. 2009)

On the positive side, the titanic work of keeping the datasets up-to-date has been facilitated by the OSM community. Leveraging the OSM crowd-sourcing mechanism the Canadian authorities have developed a much needed by any NMA, change detection process which helps the authorities to concentrate resources and effort to potential changes. This is very important when one takes into account that the update process of the authoritative database has fallen behind as it has failed to update all the originally designed spatial entities.

There are, however, challenges. The compatibility of the two datasets (in terms of semantic and attribution differences), the virtually non existence of metadata for OSM data and the differences in coverage (OSM mainly in urban areas compared to the uniform authoritative coverage), all of which stem from the differences in the two geographic information generating processes (i.e. the bottom-up and more loose OSM process compared to the top-down authoritative procedures) are still issues under consideration that need to be addressed. Moreover, there is a conflict between license and use terms of OSM and the intellectual property rights of Canadian authorities that needs to be solved.

Main lessons:

  • The Canada – OSM sunergy resulted by the need of authorities to provide up-to-date and accurate topographic maps in great magnitude and offered the opportunity to OSM community to get involved in authoritative data actively.

  • Data contributed by government and integrated into OpenStreetMap, and updated by the OSM community.

  • Updates from OSM are being used for ‘change detection’ to identify where changes occur, which is followed by data collection by the National Mapping Agency independently.

  • Differences in structure and operation mean that updates to geographic information do not move freely between the two systems.

  • Connectivity between the two different datasets faces mishit due to different terms of use and license options.

References

Beaulieu, A., Begin, D. and Genest, D. 2010. Community Mapping and Government Mapping: Potential Collaboration? Symposium of ISPRS Commission I, Calgary, Canada, June 16-18, 3p.

 

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