International audienceInstitutional base maps are today compete with a variety of datasets from the Internet. Faced with new actors (multinational corporations such as Google to communities of practice such as OpenStreetMap), historical spatial data producers need to reaffirm the legitimacy of their data. Our proposal is to analyze their strategies to (re)positioning on the web. From a corpus of 1674 sites providing environmental open data in Brazil, Bolivia and Argentina, we analyze the particular case of spatial data. Quantitative and qualitative study of visibility and value of these data allows us to approach the strategies of institutional producers. Then, the content analysis of the government portals, particularly the national spatia...