4.2.1. Free network (phase I) adjustment which involves the calculation of: 
- a global statistical test; 
- a one dimensional test (data-snooping); 
- an internal and external reliability for each observation; 
- point standard ellipses and criterion circles; 
- adjusted coordinates. 
4.2.2. Constrained network (phase Il) adjustment which involves the calculation 
of: 
- see 4.2.1 . 
- statistical test coordinates of control points. 
This compution can be performed as a least squares adjustment or as a pseudo least 
squares adjustment. 
5. ON THE USE OF THE LATEST SPARSE MATRIX TECHNOLOGY 
Module MSCAN is a compactly written, fast running least squares, and testing 
module. Provided that the allocated Ram memory space is sufficient enough to 
perform the least squares task MSCAN will be in control immedetiately after 
having read the input files created in ESCAN. Here the quasi dynamic array 
allocation technique is used. The module uses consequently sparse matrix 
techniques and the choleski factorization algorithm has been optimized. The 
overlay structure may be regarded as an optimal one. Within MSCAN an automatic 
iteration loop has been implemented. 
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