What is the minimum closure error for an Urban (Class B) survey?

The minimum closure error for an Urban (Class B) survey is set at a ratio of 1:10,000. This specification is established by surveying standards to ensure a reasonable level of accuracy for property boundaries, particularly in urban environments where tight delineations are critical for property ownership and development purposes.

The rationale behind this requirement is to maintain the integrity of land descriptions and to facilitate reliable construction and development projects in densely populated areas. A closure error of 1:10,000 means that for every 10,000 units of measurement, the cumulative error should not exceed one unit. This standard strikes a balance between the practical constraints of surveying in urban areas, where obstacles and variable sighting conditions may arise, and the need for precision in property surveys that often have significant legal implications.

In contrast, the other ratios, such as 1:2,500, 1:15,000, and 1:25,000, reflect different classes of surveys with varying levels of precision and are not applicable to Class B surveys in an urban context. These alternative ratios signify either less stringent or more stringent requirements depending on the specific classification of the survey and the expected outcomes associated with the surveying tasks.