How did the physical features of East Asia affect the route of the Silk Road

The geography of the Silk Roads then is a complex interaction between the physical and climate zones of mountain, steppe or grasslands, and river valleys and oases which often are bounded by uninhabitable desert. Thus populations could be dispersed (in the grasslands) or concentrated in the oases and river valleys. The Silk Road extended approximately 6,437 kilometers (4,000 miles) across some of the world's most formidable landscapes, including the Gobi Desert and the Pamir Mountains. Many routes were needed for trade to be more accessible.