Vertical Control for Independent Models Blocks

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.