Analysis of Sunlight Obstruction by Using Sunshine Modelwith Modified GIS Data

In this study, we evaluated the effect of geographic information system (GIS) modifications on shadow prediction accuracy using a sunshine model during the winter solstice of 2023. GIS modifications, based on actual building data and bird's-eye views, were compared to original GIS data (GISo). The results showed that modified GIS data (GISm) reduced shadow area errors by 17.58% compared to GISo when compared to observational data (OBS). This underscores the importance of GIS modifications for improved accuracy. Additionally, our assessment of total and continuous sunshine duration revealed that GISo showed discrepancies of 4 ~ 21 households relative to OBS, while GISm had discrepancies of only 2 ~ 4 households. These findings suggest that GIS modifications play a critical role in enhancing sunshine modeling accuracy. Future research should focus on comparing these models with commercial alternatives and high-resolution data to better assess sunlight rights and regional solar energy potential.