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The geodetic network in Canada is recognized to be a combination of many networks, each with its own strengths and weaknesses, and each under different jurisdictional control (federal and provincia...

The readjustment of the North American horizontal geodetic networks is scheduled for late 1985. In Canada, this will provide new coordinates and covariance matrix for a relatively sparse framework ...

A mathematical model designed for the analysis of deformations is applied to the adjustment of geodetic control networks. The estimated relative velocities of the primary control points are regarde...

Numerous statistics that can be obtained from the processing of the observations and the adjustment of a geodetic network can be used to assess the quality of the network and the observational data. The processes used for assessment and planning depend on the needs and the capabilities of the user. Statistical information derived from nonsingular vis-à-vis singular (“inner-constraint”) adjustments is discussed. Standards for the characterization of the quality of networks are reviewed. Suggestions are made on the type of information that should be directly available from a geodetic control file.

Additions to and densification of the Maritime second-order geodetic control network since its redefinition in 1979 has necessitated development of an overall densification scheme. Shown here are t...

Four principles for the application of unit cost concepts to surveying and mapping are postulated: For each product, two unit cost categories are needed: unit cost for initial production, unit cost...

Program CANDSN was developed at The University of Calgary for designing, adjusting and analyzing horizontal survey networks. The concepts and mathematics that this program is based upon are discussed in this paper. The role of interactive computer graphics as an effective technique for the entry and editing of data and the presentation of results is discussed. Experience with examples from the fields of geodesy, engineering surveying, and cadastral surveying have demonstrated the effectiveness of this program as an educational, research and working tool.

The Helmert blocking method is being used in the present effort to readjust North American geodetic networks. Combining this method with the Cholesky computational method enables the efficient solution of very large systems of linear equations. A by-product of this approach is a “partial” Cholesky square root for each Helmert block. This paper demonstrates that the Cholesky square root for the entire system of normal equations can be constructed from partial Cholesky square root blocks that are produced during the Helmert block adjustment, even though various reorderings of the unknown parameters are necessary throughout the computations. The entire Cholesky square root can be used to compute the inverse of the normal equation coefficient matrix, which is needed for post-adjustment statistical analyses.

The Canadian geodetic network that was adjusted with networks of other North American countries, in the July 1986 Continental Adjustment, included only the 8000-station national primary framework. There still remains many thousands of stations contained in regional and local secondary networks to integrate into the North American Datum of 1983 (NAD83). Secondary Integration is a cooperative project organized by member agencies of the Canadian Control Survey Committee (CCSC) which first met in 1982. Since then, members have automated and evaluated secondary network data for approximately 100 000 stations established by conventional, inertial and satellite surveying methods. The task of compiling and testing Helmert blocks for input to the simultaneous adjustment of primary and secondary networks is now underway. This paper describes the plans and progress, and some of the problems that challenge us in the NAD83 Secondary Integration Project.

The formulation of the photogrammetric block adjustment program SPACE-M has recently been extended to use relative terrestrial information. Such relative data are readily available from local survey networks with unknown biases in translation and/or orientation and/or scale with respect to the geodetic datum. The formulation in terms of coordinate differences is briefly discussed with test results using various simulated and real data sets. The implications for topographical mapping and related applications are outlined with preliminary recommendations.

In the paper the evolution of the Mexican geodetic network is described ending with its actual situation, present needs and plans for the near future, with special reference to the participation of Mexico in the readjustment of the North American network.