Green space spatial assessment and pattern optimization for towns: a case study of Jimo in Shandong Province, China Optimization of land use pattern based on eco-security:a case study in the huangfuchuan watershed GIS-based analysis of the accessibility of urban forests in the central city of Guangzhou, China Progress in the research on regional ecological security pattern Landscape pattern optimization based upon the concept of landscape functions network:a case study in Taiwan,China Optimization of wetland landscape patterns based on ecological function evaluation: a case study on the coastal wetlands of Yancheng, Jiangsu Province