Looking across the range of crowdsourced geographic information activities, some regular patterns are emerging and it might be useful to start notice them as a way to think about what is possible or not possible to do in this area. Since I don’t like the concept of ‘laws’ – as in Tobler’s first law of geography which is stated as ‘Everything is related to everything else, but near things are more related than distant things.’ – I would call them assertions. There is also something nice about using the word ‘assertion’ in the context of crowdsourced geographic information, as it echos Mike Goodchild’s differentiation between asserted and authoritative information. So not laws, just assertions or even observations.
The first one, is rephrasing a famous quote:
‘you can be supported by a huge crowd for a very short time, or by few for a long time, but you can’t have a huge crowd all of the time (unless data collection is passive)’
So the Christmas Bird Count can have tens of thousands of participants for a short time, while the number of people who operate weather observation stations will be much smaller. Same thing is true for OpenStreetMap – for crisis mapping, which is a short term task, you can get many contributors but for the regular updating of an area under usual conditions, there will be only few.
The exception for the assertion is the case for passive data collection, where information is collected automatically through the logging of information from a sensor – for example the recording of GPS track to improve navigation information.
Po Ve Sham - Muki Haklay's personal blog 
Hi Muki,
A very simple, but valuable observation. I look forward to more insights!
James
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Thanks – as the headline indicates, there are few other in store …
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Thx Muki. Good assertion! smiled at the lead in too. The passive data collection reminds me of the discussion about Big Data and Web 3.0 — seems it might apply well to crowdsourcing social science research, like public attitude trends, if that is in the realm of PPSR. In other words looking at the trends of the following searches in google: 1) is global warming happening? versus 2) is global warming manmade? just a seed of an idea…
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Thanks John, and it is an interesting question if it applies to social data.
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Great assertion Muki! A good source of discussion for the upcoming cyber summit. The observation that you cannot have a huge crowd all of the time reminds me of the old cliche: “You can’t eat your cake and have it too”
An interesting line of inquiry would be to examine factors of crowdsourcing associated with successfully maintaining a huge crowd through time – how can this be accomplished and what can be done by program coordinators/designers to accomplish this lofty goal?
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