Control Networks With Wall Monumentation: A Basis for Integrated Survey Systems in Urban Areas

Integrated information systems on urban topography, infrastructure and land cadastre, if based on numerical mapping, require horizontal control with an average of 200 m spacing of control points and accuracy of 1:35 000 in terms of the semimajor axes of the relative standard error ellipses. The authors propose to use traversing with wall monumentation (Figures I and 2) in establishing the lowest order control in urban areas. Wall monumentation (Figures 3 and 4) offers many advantages over the conventional ground markers with the same accuracy. A test network (Figure 5) with wall monumentation was established and measured in the city of Fredericton. Results are shown in Table 2. The test surveys indicate that, to achieve the required accuracy, angles should be measured with standard deviation σβ≤1."5 and distances with σs≤4 mm.