Using Solar Spatial Analyst to Calculate Global Solar Radiation, 22th Region of Tehran as the Case Study

Solar Radiation is considered as an important parameter in modeling environmental, hydrologic and biophysical processes. One of the reasons that solar radiations are not extensively used in models is the problem of its measurement in different points. Solar Analyst Viewshed Algorithm makes possible calculation of the topographic effects on solar radiation at local and landscape scales. With respect to lack of LIDAR data and accurate and updated information, this article studies a modeled solar radiation and rate of radiation using GIS Solar Analyst Viewshed Algorithm and regarding DEM and metrological parameters regionally (District 22 of Tehran). Summary of the radiation statistics for July (maximum, minimum, and mean) for six sets of slopes and landscape in District 22 were analyzed. The results indicate that the southward slopes receive further radiation values than the northward ones during July. This will have a crucial role in architecture, urban development model, and photovoltaic installations.