I had the good fortune a couple of weeks ago to attend a series of workshops at Nottingham University to explore how Crowd Sourced data can contribute to the work of the National Mapping and Cadastral Agencies. The great and the good were there in abundance with a wide range of participants from the NMAs, academia and industry. Even the likes of Google, ESRI and the OGC have sufficient interest in the concepts to send representatives. The discussions were wide and varied but a number of key concepts came out.
Financial – We in the UK are fortunate in that we have a world class mapping agency in the form of the Ordnance Survey, but not every country has the will or the ability to support agencies to same extent. Indeed, it was generally agreed amongst the participants that the likelihood was that investment in mapping agencies across Europe is likely to decrease as national finances are reprioritised. Therefore, all the NMAs, including the OS, are aware that they will need the help of the “Crowd” to maintain and expand the current coverage. This presents opportunities and challenges for the NMAs about how to collect and incorporate such data.
Public Expectation – with the advent of on-line mapping sources such as Google and Bing (and OpenStreetMap) the general public expects mapping to be free. How do the NMAs compete in this environment to support themselves financially, particularly when open government initiatives are encouraging (demanding?) that the NMAs freely supply some of the mapping data to the general public? (See the OS OpenData initiative)
Motivation – How can a reliable and sustainable crowd be established? For general purpose mapping, both the “Crowd” and the NMAs do a pretty good job of collecting data in urban areas. The “Crowd” are not so good at collecting data in the rural and remote regions. Even in urban areas the majority of data is collected by less than 10% of all participants. If NMAs are to augment their data with “Crowd” data then they need a group of active and committed participants with the appropriate skills. Some consideration has been given to recruiting members of specialist groups such as rambler and park rangers. In Africa, the GroundTruth initiative are training, and in some cases paying, the local communities to map their environment. The challenge in Europe is how to motivate the “Crowd” to map those areas not already covered.
Quality – There are questions over the quality of the data sourced from the “Crowd”. In some cases the quality of the data may be better, as the “Crowd” has better local knowledge in terms of name, building use etc. In other cases the quality of the data is variable and can depend on skill, equipment, terrain etc. (Haklay 2010, suggests an average error of OSM against OS Data of +/-6m). It is necessary, therefore, to establish a measure of quality for the crowd-sourced data to gain trust by the NMAs to permit inclusion of the data.
Fitness for purpose – Establishing fitness for purpose is an important consideration. NMAs strive for “super quality” across all their products and in many cases this “super quality” is necessary. However, if the public want a street map to aid visual navigation then the quality of the information just needs to be “good enough”. Personally, at the moment, I have my doubts about whether crowd sourced data is “good enough” for turn by turn navigation ala TomTom.
Licences – how will the current licence models work if some if the data being supplied by the NMAs is supplied by the “Crowd”?
Legal – data provided by the NMAs is considered to have a level of legal standing. How can this standing be maintained if it is being collected by the “Crowd” the participants of which may have varying degrees of skill? However, under the umbrella of something is better than nothing, the Norwegian Mapping Agency has a scheme underway which will encourage citizens to map their boundaries with neighbours and establish a legal contract on the extent of these boundaries. The Norwegian Mapping Agency will assist this process with remote learning resources are surveyor support where necessary.
There seem to be quite a few hurdles to be overcome if Crowd Sourced data is to find its way into National Mapping Agencies but, as the Norwegian experience shows, over time the NMAs will need to make use of the “Crowd” if they are to fulfil their role. In the first instance this may be as simple as using the “Crowd” to identify significant areas of change, but later, a “Big Society” approach may take off where trained (and I think training is a key issue here) volunteers provide a service back to the community. This may not be as high profile as some of the caring initiatives but it is still likely to be important. In the meantime Crowd Sourced data, and more particularly OpenStreetMap, still offers an easily accessible service to the general public and forms the basis for the specialist mapping information for cyclists, ramblers , canoeists and the all the other active types. We still need additional initiatives for the non-active types; what about a specialist pub map?
Brendan D. Mason, Technical Consultant