English: Solar resource: GLOBAL HORIZONTAL IRRADIATION (GHI) - this solar resource map provides a summary of the estimated solar energy available for power generation and other energy applications. It represents the average daily/yearly totals of global horizontal irradiation (GHI) covering a period from 1994/1999/2007 (depending on the region) to 2018. The underlying solar resource database is calculated by the Solargis model from atmospheric and satellite data with 10-, 15- and 30-minute time step. The effects of terrain are considered at nominal spatial resolution of 250 m. There is some uncertainty in the yearly GHI estimate as a result of limited potential for regional model validation due to a lack of high quality ground measurement data, which is estimated to vary regionally from approx. 4% to 8%. GHI is the most important parameter for energy yield calculation and performance assessment of flat-plate photovoltaic (PV) technologies.