Drainage networks allow the extraction of topographic parameters that are useful for basins characterization and necessary for hydrologic modelling. One way to obtain drainage networks is by their extraction from Digital Elevation Models (DEMs). However, it is common that no freely available DEMs at regional or national level exist. One way to overcome this situation is to use the available free Global Digital Elevation Models (GDEMs). However, these datasets have relatively low spatial resolutions, 30 and 90 meters for ASTER and SRTM, respectively, and it has been shown that their accuracy is relatively low in several regions (e.g., Kääb, 2005; Mukul et al., 2017). In this study a methodology is presented to improve the positional accuracy of the drainage networks extracted from the GDEMs using crowdsourced data available in the collaborative project OpenStreetMap (OSM). In this approach only free and global datasets are used, enabling its application to any location of the world. The methodology uses elevation points derived from the GDEMs and the water lines extracted from the collaborative project OSM to generate new DEMs, from which new water lines are obtained. The methodology is applied to two study areas and the positional accuracy of the used data and the obtained results are assessed using reference data.
In this paper, we defend the main claims of our earlier paper “Mental Fictionalism as an Undermotivated Theory” (in The Monist) from Gábor Bács’s criticism, which appeared in his “Mental fictionalism and epiphenomenal qualia” (in Dialectica). In our earlier paper, we tried to show that mental fictionalism is an undermotivated theory, so there is no good reason to give up the realist approach to the folk psychological discourse. The core of Bács’s criticism consists in that our argumentation rests on an equivocation concerning the folk psychological concepts of conscious experiences. In our present argumentation, at first, we shortly recapitulate our earlier argumentation and Bács’s main objection to it. After that, we argue against the case of equivocation, claiming that it rests on a highly implausible and unsupported verificationist approach. Lastly, in answering another remark of Bács’s, we discuss the possibility of a realist mental fictionalism and conclude that it is an incoherent standpoint.