The early research phase established the seven sites as a connected material network across Vietnam rather than a set of isolated sampling points. Spanning roughly from 21° to 10° latitude, the sites trace a north–south geographic arc through diverse climate zones, soil conditions, fiber sources, biopolymers, and cultural landscapes. Each location was selected for its capacity to support both material research and architectural application. Together, the sites offer a range of ecological and geological conditions, connections to current or future projects, proximity to culturally significant communities, and potential for traditional and experimental earthen construction. The selection also considered practical factors: sufficient soil reserves for future pilot production, local accessibility, and the presence of networks that can support fieldwork, sampling, and long-term collaboration.