Public participation GIS versus geolocated social media data to assess urban cultural ecosystem services: Instances of complementarity

Cultural ecosystem services (CES) are important components of urban quality of life. Public participation GIS (PPGIS) is widely used to assess and map these services. However, it is often a time-consuming exercise with which only small spatial and temporal scales can be addressed. Assessments based on geolocated, passively crowdsourced data from social media present new opportunities to assess CES through a large amount of available data and for broad spatial and temporal scales. We assess the potential of these two methods to substitute, supplement or complement each other in terms of the qualitative information they provide (i.e., landscape features of interest and CES). We take as a case study seven green and blue open spaces of the city of Haifa (Israel), each presenting different elements of interest in the landscape and degrees of accessibility. Results indicate that the two methods provide unique results and are complementary in many instances. We discuss the representativeness of the social media data, the strength of the two methods with respect to the qualitative information obtained, the specificities related to the urban context and the instances of complementarity. We suggest that crowdsourced social media data should be included in broad, multi-methodological approaches to CES.