Vertical Control for Independent Models Blocks

by Wolfgang Faig, Assoc. Prof. of Surveying Engrg.; Dept. of Surveying Engrg., Univ. of New Brunswick, Fredericton, N.B., Canada,
Thomas Mathew, Photogrammetric Officer; Surveys and Mapping Div., Ministry of Lands, Housing, and Urban Development, Dar Es Salaam, Tanzania,
Sabry El Hakim, Grad. Student; Dept. of Surveying Engrg., Univ. of New Brunswick, Fredericton, N.B., Canada,


Serial Information: Journal of the Surveying and Mapping Division, 1977, Vol. 103, Issue 1, Pg. 37-46


Document Type: Journal Paper

Abstract: In simultaneous block adjustments vertical control points need to be located in dense cross chains if no auxiliary information is available. One additional perimeter control point each between them strengthens the solution, and a further reduction of the vertical block deformation is achieved by normalizing the x-residuals in the projection centers. The use of auxiliary data leads to substantial saving of vertical control points. The interaction between vertical control point distribution, statoscope-, APR-, lake data, and combinations of these is studied with several well-controlled independent model production blocks adjusted with PAT-M-43. The tests indicate that the bridging distance can be increased to the extent that there is virtually no need for control points within the block for small and medium-scale mapping purposes.

Subject Headings: Data processing | Information management | Deformation (mechanics) | Lakes | Hydrologic data | Mapping

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