Resumen
Over the last ten years development of Spatial Data Infrastructures (SDIs) has become an important subject being a driving force towards the vision of Digital Earth increasing the availibility and accessibility of geographic information exchange and sharing of spatial data. Worldwide, large investments have been made to develop SDI initiatives. Given the expenditure and society?s interest in the proper and effective use of these funds, it has become a necessity to have reliable methods and instruments to assess these SDI initiatives. However, the assessment and evaluation of SDIs is an extremly challenging task due to a number of reasons. Although the literature provides a number of assessment methods, all of them either concentrate on only some aspects of an SDI or on one specific region, or are still conceptual in nature (Crompvoets et al., 2009). In this paper, the authors introduce a new pragmatic appoach to identify, analyse and assess SDI solutions having the principles of Digital Earth, INSPIRE and GMES in mind. This approach has been developed by the Thematic Network eSDI-Net+ and has been validated in a comprehensive survey involving about 200 SDIs from 26 European countries as well as different stakeholders involved in the creation and use of SDIs throughout Europe. The main purpose of the paper is to introduce this unique SDI assessment methodology as well as to demonstrate the possiblities of its practical application. Furthermore, the paper critically reflects the experiences made and lessons learnt by applying this methodology in a survey of the subnational SDIs in Europe in 2008-2010 and discusses the main implications for future SDI research, in Europe and worldwide.