Which point is established as the reference for all surveys in the municipality or locality?

• A. BLLM No.2
• B. BLLM No.1
• C. NAMRIA Reference Point
• D. LMB Reference Point

Answer: (B)

In surveying, a fixed, known point within the locality serves as the reference from which all other measurements are taken. This local primary benchmark provides a stable origin for coordinates and ensures that surveys done by different crews in the same municipality line up on a single map. BLLM No.1 is designated as that reference point for all surveys in the municipality. It is established and permanently marked so that every subsequent survey can tie into it, building a consistent local grid that also relates to the national framework through connections to NAMRIA’s network. While NAMRIA references exist at the national level, they aren’t the single reference point for all local surveys; a local primary benchmark like BLLM No.1 serves that role. BLLM No.2 would be a secondary point used for checks, not the primary reference.