This is a Goodchild works that serves as a brief introduction to the topic of VGI. Although it is done in 2007, when computational power and artificial intelligence was just in the start-up phase. We do see how VGI serves as a main data source in the field of Cartography and some geographic related fields. However, by highlighting the contributions of VGI, he also pointed out the limitation of relying on VGI as a source of geographic data – the validity, accessibility, and authority of data.
Nowadays, we see OSM and Google Maps are used as major sources of many spatial analytical researches, especially in a larger extent when primary data collection became time- and human-consuming. Just as Goodchild argues, from the perspective of researchers, the availability of spatial data can be extracted from VGI sources is promised, there are questions need to be asked about synthesizing and validating VGI data to increase the accuracy of data.
Who contributes to the data? This is the question unsolved even after 12 years after he wrote this paper. This particular question asks the coverage of population that VGI data might represents, the area it covers, and the scope it uses. Why do people do this? Another question relating to the bias and incentive of VGI data, which potentially influencing the result from researches using VGI data. Also, with various available VGI data sources, how we can incorporate them together to cross-validate, references each other to generate better accuracy for our objective is the question I would like to seek for an answer. As well as how to cross referencing different sources (other than VGI) to VGI data to increase its validity, and somehow gives them authority is another interesting topics I am eager to learn.