Finding a suitable location to build a bridge involves considering several physical geography factors. Look for areas with stable bedrock or soil to support the bridge's foundation. Avoid areas prone to erosion or landslides. Analyze the water depth, flow rate, and potential for flooding or ice jams in rivers or streams.

For setting up bases, seek elevated ground for better visibility and security. Analyze the terrain for accessibility, ensuring it's suitable for transportation of materials and personnel. Consider proximity to resources like water and construction materials.

Combining these factors through physical geography methods involves field surveys, topographic maps, geological assessments, and hydrological studies to ensure the bridge's stability and the bases' functionality.