Delineating urban growth boundaries (UGBs) by combining the land-use/land-cover (LULC) change simulation method has become common in recent studies. However, few of the existing studies have integrated multi-source big data to analyze the driving factors of LULC dynamics in the simulation. Moreover, most of previous studies mainly focused on the UGBs delineation in macroscale areas rather than small-scale areas, such as the county area. In this study, taking Xinxing County of Guangdong Province as the study area, we coupled a system dynamics (SD) model and a patch-generating land-use simulation (PLUS) model to propose a framework for the LULC change simulation and UGBs delineation in the county area. Multi-source big data such as points of interest (POIs), night-time light (NTL) data and Tencent user density (TUD) were integrated to analyze the driving forces of LULC change. The validation results indicate that the coupled model received high accuracy both in the land-use demand projection and LULC distribution simulation. The combination of multi-source big data can effectively describe the influence of human socio-economic factors on the expansion of urban land and industrial land. The UGBs delineation results have similar spatial patterns with the LULC change simulation results, which indicates that the proposed UGBs delineation method can effectively transform the LULC simulation results into available UGBs for the county area. It has been proven that the proposed framework in this study is effective for the LULC change simulation and UGBs delineation in the county area, which can provide insight on territorial spatial planning in the county area.

It is of great significance to explore landscape pattern changes around urban areas to maintain regional ecological security and encourage sustainable development. Few studies have focused on the small cities located in the mountain regions. In this study, we established an ‘urban-rural’ gradient, and combined with landscape metrics to analyze the spatial-temporal changes of the landscape pattern around cities located in the Hengduan Mountain region in China. We also explored the impacts of topography on urban sprawl using the ‘relief degree of land surface’ index. Our results showed that: (1) There was an inverse relationship between the urban sprawl and restricted topography; (2) From the city center to rural areas, the landscape dominance degree and connectivity decreased initially and then increased, while the diversity presented an opposite trend and the shape complexity increased first and then fluctuated; (3) For temporal changes, in the internal buffers, the landscape dominance degree and connectivity increased, and the shape complexity and diversity decreased. However, in the outer buffers, the landscape showed opposite trends. It is advisable to use gradient and landscape metrics to explore landscape pattern changes. Similar to cities on plains, the landscape around mountain cities exhibits a circular structure, however, it also possesses unique characteristics when facing topographic restrictions.