bluuebunny/crossref_metadata_2025 huggingface dataset:
Mine Surveying: An Appraisal of Some Newer Instruments and Techniques
Authors: Sheehan J. F.
Published: July 2019

The surveys office at Mount Isa Mines Limited in northern Australia uses modern surveying techniques such as electronic distance measuring, gyro orientation, laser alignment and computerization. An assessment of these techniques indicates practical advantages such as higher accuracy in underground and surface survey nets and a considerable saving of time. Some physical modifications to the instruments are necessary to facilitate their use in underground conditions. Use of small electronic desk computers instead of a large computer seems to be advantageous in daily routine computations.
New Techniques in Mine Orientation Surveys
Authors: Chrzanowski Adam J.
Published: July 2019

Underground surveys in mines can be oriented either by single-shaft plumbing, double-shaft plumbing with an accompanying connecting traverse, or by gyro-theodolite observations. The relative merits of these methods are discussed.

Descriptions are given of two types of laser plummets and of a laser centering detector, which were designed and manufactured at the University of New Brunswick and which facilitate optical shaft plumbing of high precision.

Details are presented of surface and underground traverses, connecting mine shafts, in which the distances were measured with the new Wild D1-10 and tellurometer MA-100 infrared instruments.

Finally, gyro-orientation methods are outlined. The various errors affecting gyro-azimuth determinations are described in detail and hints are given for ensuring high accuracy.
The Modified Transit Method of Observation With the Wild GAK-1 Gyro Theodolite
Authors: Bennett G.G.
Published: July 2019

In UNISURV Report No. 15, 1969, this author gave the theory and practice of methods that have been developed for the transit and turning point methods of observation with the gyro theodolite to reduce the total observation time. Since the publication of that report, a longer experimental series of observations has been made to test the repeatability of the modified transit method and to assess the reliability of the reduction process. The results of this experimental series are given together with an analysis of various reduction methods.
A Comparative Statistical Study of the Methods of Weighting Observations
Authors: Tiwari R. S. , Rao K. R. B.
Published: July 2019

The simple arithmetic mean is generally accepted as the most probable value. However, in a set of a small number of observations, a weighted mean is often regarded as being better than the simple arithmetic mean, even if the latter were obtained after rejecting the outlying observations. A number of methods of weighting have been put forward from time to time.

This paper presents the result of a statistical study designed to discover whether any of the weighting methods produce values superior to the simple arithmetic mean. The study follows the same lines as a previous paper [Oswal and Tiwari 1965]. Of the six methods compared, only that of Jeffreys has been found to give values statistically superior to the simple arithmetic mean. The use of Jeffreys’ mean is suggested, therefore, for survey work, especially if these values are required for further rigorous adjustment purposes.
Automation in Hydrographic Charting
Authors: Boyle A. R.
Published: July 2019

This paper provides a general description of the concepts, hardware and programs of the basic system of automatic cartography designed by the University of Saskatchewan for the Canadian Hydrographie Service. The basic system includes an automatic drafting system and a semi-manual digitizing unit.

Also described are additions to the basic system which, during the development, have shown themselves to be important and which have been experimentally examined for feasibility. These additions include an interactive display system to be used in computer-aided compilation and in data-base incorporation, an extended digitization system, a visual monitoring system and typed output facility.
Analysis of the Primary and Secondary Control Networks of New Brunswick — Implications for a Readjustment to Satellite Control
Authors: Krakiwsky E. , Konecny G.
Published: July 2019

Various problems associated with the adjustment of geodetic control networks in Eastern Canada are discussed. Results of analyses of the primary control networks in New Brunswick indicate that significant distortions are present and are due mainly to the Bowie Method of adjustment used when the 1927 North American Datum was adopted. The “free adjustments” made by the authors show that the proportional accuracy can be improved from the present lowest value of 1:20,000 to as high as 1:200,000. Other analyses cited in the paper indicate that there may be merit in combining first- and second-order control networks in a simultaneous adjustment. Some details are given on merging the first-order terrestrial networks in Eastern Canada with one triangle of the North American satellite triangulation network in a simultaneous adjustment.
The General Term in the Expansion for Meridian Length
Authors: Schmid Erwin
Published: July 2019

The series for arc length of the meridian of an oblate ellipsoid of revolution is developed to the nth term in powers of e2 and of the sine and cosine of the geodetic latitude. This type of expansion seems to be more efficient for use in electronic computation than the traditional series in terms of multiple angles ofɸ. Inclusion of the general term allows any desired degree of precision and an estimate of the neglected portion of the function.
Image Deformation and Methods For Its Correction
Authors: Ziemann H.
Published: July 2019

Image deformation is an error that influences the very base of any photogrammetric operation, the photographic image, and, therefore, its correction is of prime importance. There is no doubt that corrections for image deformation should be applied to the original image rather than at a later stage of the photogrammetric compilation.

Image deformation corrections can be carried out most effectively if réseau photography is used. Several kinds of réseau are possible; however, only a réseau projected in central projection and simultaneously exposed with the aerial photograph enables a correction to be made for the effects of insufficient film flattening. This is a more important source of image deformation than film deformation.

A number of results are given which prove the superiority of image deformation correction methods that derive, for each point to be corrected, a correction using only the four réseau points surrounding those points, or the réseau point nearest to that point. The effectiveness of these correction methods depends on the density of the réseau.
Precise Traverse in Major Geodetic Networks
Authors: Adler R. K. , Shmutter B.
Published: July 2019

Investigation of a precise traverse network is presented on the basis of computer simulation of observations. Various aspects affecting the accuracy of final adjusted coordinates are considered, such as the density of Laplace control, the weighting of the various types of observations and the sensitivity of the system to weights. The simulation approach permits the evaluation of results through comparison of adjusted values to an artificially created “errorless” standard.

The advantages of a modern precise traverse are considered with a view to its extensive utilization in major geodetic networks.
Winter Photographs in Cadastral Surveying (A Suggestion)
Authors: Blachut T. J.
Published: July 2019

There are obvious reasons why winter photographs are not suitable for general mapping of the country. In cadastral mapping, however, there are certain economic and technical arguments for the use of winter photographs. The author discusses these factors and quotes the results of specially arranged investigations. An operational experiment is suggested to provide more comparative data on the subject.
Rho-Rho Loran-C for Offshore Surveys
Authors: Eaton R. M. , Grant S. T.
Published: July 2019

Using atomic clocks, the United States Coast Guard has recently pioneered a precise distance measuring version of Loran-C, for positioning by two ranges when within about 1,700 km of the transmitters. In May 1971 the authors took advantage of the calibrated Decca Lambda survey chain, being used by the CSS Baffin on the Grand Banks of Newfoundland, to evaluate the accuracy and reliability of this ‘rho-rho’ Loran-C.

This paper outlines briefly the principles of Loran-C and the associated problems of geodesy and radio wave propagation. The procedures for operating rho-rho Loran-C are described and the results of short term (hours) and long-term (weeks) accuracy tests are given.

Rho-rho Loran-C is an ‘extrapolative’ navigation system that requires periodic checks at a reference point to adjust accumulated error. It was found that, by taking reasonable precautions, range measuring accuracy of about 200 meters can be maintained over five days or so.
Geodetic Control from Doppler Satellite Observations
Authors: Krakiwsky Edward J. , Wells David E. , Kirkham Perry
Published: July 2019

Integrated Doppler satellite observations, obtained from the Transit satellite system, are reviewed. The mathematical model relating these observations to coordinates of the observing station is given. The least squares adjustment of the observations is discussed, including uncorrelated and correlated weighting of the observations. Doppler satellite positioning results for single station tracking are presented, in which a repeatability of five meters was achieved. Datum translation components are discussed. Interstation distances between six pairs of stations in eastern Canada, determined from simultaneous Doppler satellite tracking at the pairs of stations (translocation), are compared with results from first-order terrestrial networks and from satellite triangulation and are found to have an agreement, on average, of 2.8 ppm with the best available terrestrial network and 6.2 ppm with preliminary satellite triangulation results. Both single station and translocation results justify correlated weighting of the observations.
Use of Laser in Precision Leveling
Authors: Chrzanowski Adam , Janssen Hans-Dirk
Published: July 2019

Three new instruments for precision leveling have been developed at the University of New Brunswick: the Photoelectric Laser Level; the Laser/Ni-007, a combination of He-Ne laser with the Zeiss-Jena Ni-007 geodetic level; a Self-Aligning Centering Detector for laser leveling with long sights in a turbulent atmosphere. The instruments have been laboratory and field tested in a differential geodetic leveling and in leveling across rivers. First-order geodetic accuracy has been obtained.
A Program for Analytical Aerial Triangulation
Authors: Allam M. Mosaad
Published: July 2019

This paper presents the recent development by the Research and Development Section of the Topographical Survey Directorate, of a procedure and computer program for the Analytical Processing of Image Coordinates in analytical aerial triangulation. The program APICOR was developed to obtain a general image coordinate processing program for production use. As input, the program accepts the plate coordinates measured on a stereo- or monocomparator. The output is in the form of refined image coordinates, independent models, sections or strips or a combination of any two. The APICOR program features automatic rejection criteria, blunder elimination of erroneous data at the different stages of image coordinate corrections, relative orientation, model, section and strip formation. The program is coded in the Fortran IV language to run on the CDC 6400 computer.
The Development of Air-Photo Interpretation in Canada
Authors: Parry J. T.
Published: July 2019

Aerial photography has come of age in Canada and is now widely used for both cartographic and interpretive purposes. In this historical review, the development of air-photo interpretation in Canada is traced from the earliest times to the present day. The major milestones are identified, and an attempt is made to show the pattern of development and the trends in photo-interpretation work in Canada since the first air photos were obtained in 1883. Separate sections are devoted to air-photo interpretation in forestry, agriculture and crop inventory, engineering, physiography and terrain analysis, wildlife, and social studies. An extensive reference list, which will serve as a base-line reference for current researchers and a source document for future reviewers, is an integral part of the review.
Planimetric Accuracy of Infrared Line Scan Imagery
Authors: Derenyi Eugene E.
Published: July 2019

Two strips of imagery, produced by a HRB-Singer Reconofax XIIIA scanner at a scale of 1:17,000, were used to ascertain the planimetric point accuracy attainable with a typical infrared line scan system. About one hundred points were selected on each strip and their image coordinates measured in a comparator. Ground positions of these points were obtained from a 1:4,800 scale map. First the imagery was fitted to planimetric control points by linear conformal transformation, then by affine transformation and finally by a polynomial transformation, which was designed to correct displacements caused by errors and changes in the interior and exterior orientation of the sensor. The root mean square errors of discrepancies at check points reached 7 mm at image scale after the first transformation, but decreased to 0.3 mm as a result of the polynomial transformation.
Geodetic Networks in Mexico
Authors: Villasana J. Alberto
Published: July 2019

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.
Geodetic Networks in Canada
Authors: McLellan C. D.
Published: July 2019

Geodetic networks in Canada are concentrated in the southern populated regions and tend to reflect immediate demands. A long-range plan has now been undertaken to establish and maintain horizontal and vertical control frameworks that can adequately meet needs in any part of the country. A shorter term phase of this plan is the new North American Datum and adjustment, and this is the current priority. Doppler satellite positioning will play an important role in Canadian horizontal control networks.
Internal and External Consistency of Doppler, Satellite-Triangulation, and Terrestrial Networks
Authors: Wells D. E. , Krakiwsky E. J. , Thomson D. B.
Published: July 2019

Three sample networks in Atlantic Canada are compared: one eight-station Doppler satellite network, one triangle of the North American densification of the USNGS world satellite triangulation network, and one terrestrial triangulation network. The method used to compute the Doppler network is described. The internal consistency of each network is assessed through analysis of covariance matrices. The externa! consistency between the Doppler and satellite triangulation, and between the Doppler and terrestrial networks is assessed by comparing the interstation distances in one network with the appropriate confidence regions in the other.
Reduction of Doppler Satellite Data Observed in Canada
Authors: Kouba J.
Published: July 2019

The methods and mathematical model used for Doppler data reduction are briefly discussed. The problems experienced are described with plans and recommendations for future processing of the data.
Positioning of Horizontal Geodetic Datums
Authors: Vanicek P. , Wells D. E.
Published: July 2019

This paper treats the classical problem of positioning horizontal geodetic datums. By ‘classical problem’ we mean the problem we face when dealing with the usual horizontal control networks, as opposed to some of the more modern ideas, such as the use of geocentric coordinates, or the ideas of Hotine [1959, 1969]. Our basic assumption is that a coordinate system is a fixed framework (i.e., invariant with respect to network adjustment, readjustment, or expansion) for describing geodetic networks. Our view is that a coordinate system and the network it describes are two different things (this view is not universally accepted within the geodetic community).
Détermination du géoïde astro-gravimétrique par la méthode de collocation par moindres carrés
Authors: Lachapelle Gérard
Published: July 2019

The method of least squares collocation is briefly outlined. Its application to the determination of the astrogravimetric geoid (in fact, satellite data can be used as well) and the difficulties encountered are discussed. By the use of this method, it is possible to combine all types of geodetic data available in order to obtain an optimum solution for the geoid. It is also possible to determine consistent geodetic parameters necessary for the definition of a geodetic reference system. These parameters include the position of the existing astrogeodetic reference ellipsoid with respect to the geocenter to which the gravimetric and satellite data are referred.
Geodetic Coordinates in Four Dimensions
Authors: Mather R. S.
Published: July 2019

An attempt is made to summarize arguments for defining geodetic coordinates in the four-dimensional sense, in a manner that will permit their use without undue complexity over extended periods of time for geophysical and geodynamic purposes. Such arguments cannot be isolated from the consideration of techniques for position determination with the highest possible precision for other purposes that are potentially beneficial for the global community, in view of the capital expense involved. The types of observations that offer the most promise in the achievement of these goals are also a factor in the development.

A simple system of reference that fulfills the basic requirements of geodetic determinations of this type is described in the context of inter-relations between the geometric and dynamic characteristics of the earth. System requirements for the implementation of such a scheme are outlined.

There is disagreement on whether geodesy can contribute any data of significance in the short term, apart from that for studies of gross effects in local regions, toward understanding earthquake mechanisms. However, the overall cost-benefit-oriented geodetic requirements, calling for determinations of the highest precision, appear to warrant the maintenance of a worldwide geodetic network and associated measuring systems in a manner that would also permit the determination of those time variations in geodetic coordinates with global relevance.

A historical perspective makes it mandatory that such a scheme be initiated in the next decade, in view of the favorable portents for a significant improvement in the measuring precision.
The Strength of Continental Terrestrial Networks
Authors: Meissl P.
Published: July 2019

The paper surveys the research work on the theoretical analysis of large networks performed by the author over the past several years. Continental networks are classified and the geometrical strength of these network classes is discussed.
Distortions of Canadian Geodetic Networks due to the Neglect of Deflections of the Vertical and Geoidal Heights
Authors: Thomson D.B. , Nassar M. M. , Merry C. L.
Published: July 2019

In North America, geodetic observations have not been, generally, rigorously reduced to the reference ellipsoid. To investigate the effects on the coordinates of the points in some networks, several adjustments have been performed. In each adjustment, the individual contributions, as well as the total effect, of the geoidal height and deflections of the vertical have been investigated. The distortions are shown to be systematic, and are of practical significance in a continental context.
The Adjustment and Analysis of Very Large Networks
Authors: Ashkenazi Vidal
Published: July 2019

This paper is an abridged version of a communication, “An assessment of the proposed readjustment of the North American geodetic control networks,” which was presented at the Symposium. It reviews the current methods of solution and analysis of very large geodetic control networks. These include the Choleski decomposition compatible banded forms and corresponding mesh-point numbering techniques, rigorous block methods, iterative procedures and some recently used approximate techniques.
Influence de l’incertitude des paramètres tenus fixes dans une compensation sur la propagation des variances-covariances
Authors: Blaha Georges
Published: July 2019

This work (condensed report of the same title and by the same author), although applicable to a number of least squares adjustment problems, was inspired by adjustments of two-dimensional geodetic networks. Such adjustments are carried out separately for different orders and in general the coordinates of the points belonging to a higher order are kept unchanged for obvious practical reasons. However, should the uncertainty of the “fixed” parameters be neglected in the variance-covariance propagation, the outcome of an adjustment would be too optimistic and without any real meaning. The main task of this study is to correct the variance-covariance matrices for the contribution of this uncertainty considering the “General Least Squares Method” with weighted, unknown, or some weighted and some unknown parameters. Such an approach represents a generalization of the treatment described in the reference paper in a sense that it allows for the inclusion of completely unknown parameters in the mathematical model.
The Importance of Ordering Systems of Geodetic Normal Equations
Authors: Gergen John G.
Published: July 2019

An investigation was performed to indicate the importance of ordering systems of normal equations. Two results were obtained: the precision of adjusted positions of 840 points is unaffected by even a casual approach to ordering, and computer time (and cost) can increase significantly if ordering is not performed.

The sorting method proposed to achieve ordering is not new, it is very simple, and the cost is negligible. The resulting normal equations are neither minimum band width nor minimum fill-in, but near minimum conditions are obtained in the process.
Least Squares Solution by Diagonal Partitioning
Authors: Zimmerman Dale S.
Published: July 2019

A method has been developed in the Geodetic Survey Squadron to solve very large sets of weighted, linear observation equations on a computer with minimal core storage. The upper triangular portion of a symmetric matrix is partitioned and inverted to obtain the variance-covariance elements and the solution vector. Observation equations are stored externally with the zero elements eliminated. The normal equation partitions are formed while reading one observation equation at a time from an external storage device. The inversion technique requires storage of only two partitions in core with the remaining partitions residing on a random access device. A set of 25,000 observation equations and 2,003 unknowns was solved in 35 hours on an IBM 7094/MOD 1 using 20,000 words of core and external disk storage. Partition size was 91×91. An increase in partition size significantly reduces execution time. The solution can be interrupted and restarted to avoid long continuous computer runs.
Canadian National Positional Control Survey Data File
Authors: Porter T. A.
Published: July 2019

For the past three years the Geodetic Survey of Canada has been developing a computerized storage and retrieval system for geodetic control information. Work has been concentrated on a pilot project to test system concepts. The computerized data file being developed will store coordinates, elevations, observed data, information on adjustments, monumentation, interconnections, identification photography and the text of descriptions. This constitutes virtually all the control survey information requested from the Geodetic Survey of Canada. The data records for each point are stored in geographic order and accessed by an indexed sequential information retrieval system. This scheme permits relatively rapid retrieval of records by location or point number. It is also possible to retrieve by network number, line number or by any other specified parameter in the data record.

The output can be printed in several formats and the modular nature of the system allows easy addition of new formats. Retrieved data can also be plotted by specifying the scale, projection and the area covered.
Problems Arising from Redefinition in Densification Surveys
Authors: Chrzanowski Adam , Canellopoulos Nicholas
Published: July 2019

The redefinition has been considered as a necessary step to improve the primary control network, which at the present does not satisfy the accuracy requirements of all the users.

In view of the existing distortions in the primary control and in view of the forthcoming redefinition, the user who is involved in a densification survey faces the following questions:

1) how to perform the adjustment of the secondary networks in order to be independent of the distortion of the primary network, 2) how to take the advantage of those parts of the primary network that satisfy his requirements.

If the two questions are answered, one has to solve a problem on how to transform, in the best way, the established secondary network into the redefined coordinates system. The authors try to give an answer to those questions considering the following four cases:

1) the relative accuracy between the higher order points is much better than the relative accuracy of the same points belonging to the densification network; 2) both primary and densification methods have the same accuracy; 3) the relative accuracy of the higher order network is worse than the corresponding of the densification network; 4) the relative accuracy of the points of the higher order network is unknown. The authors advocate that a free adjustment and a fitting method should answer the problem.
Mathematical-Statistical Methods for the Analysis of Aerial Triangulation Adjustment Errors Using a Computer Program
Authors: Allam M. Mosaad
Published: July 2019

In practice, photogrammetrists use a single statistic reliability interval criterion, based on the mean square errors, to judge the accuracy of adjustment of photogrammetric blocks. Even in some cases, if the practical and theoretical distributions of frequency interval agree, such a test does not make it possible to establish the closeness of their convergence nor the degree of their difference. In other words, to get a complete picture of the character of the distribution of errors in the adjusted photogrammetric blocks, it is insufficient to investigate any single statistic.

In the Research and Development Section of the Topographical Survey Directorate, a computer program (SABA) has been designed to analyze the errors of photogrammetric block adjustments, compute various statistical parameters and check the sample distribution using Kolmogorov criterion. Based on the decision taken, the correspondence between the empirical and theoretical distribution series are checked using the criterion χ2.

The program divides the adjusted block to make a comparative evaluation of accuracies in the different sub-blocks. In this case, in addition to Kolmogorov and χ2 tests, the program checks the reliability intervals of the means and mean square errors of the samples and uses Fisher criterion ‘F’ to check the hypothesis of the equality of dispersion. SABA is coded in Fortran IV and Compass for the CDC CYBER 74 and requires a central memory of 28K decimal works. SABA is the acronym for Statistical Analysis of Block Adjustment.
35MM Photography, Viewing and Cataloguing System for Remote Sensing Data
Authors: Scherz James P. , Singh Ramchandra , Rinehardt Gregory
Published: July 2019

For many environmental monitoring applications, 35mm color and color infrared images are just as adequate as larger sized photography taken by cameras designed for high metric accuracy. Also a 35mm system is many times more economical and versatile. This paper describes a 35mm system utilizing two bulk-film, motor-drive cameras that produce in effect 35mm color and color infrared microfilm that can be viewed, catalogued, retrieved, and, in all other ways, handled as conventional microfilm. Minor modifications to standard microfilm viewers allow projection of selected frames to a base map; step wedges can be easily photographed and density analysis made with a microdensitometer, and slide copy equipment can copy selected frames for illustration work. This 35mm bulk-film system has proven a most versatile, economical and practical method for operational remote sensing environmental monitoring.
Evaluation of Sopelem Presa 226RC Plotter for Independent Model Triangulation
Authors: Moffitt Francis H.
Published: July 2019

The Presa 226RC is a first-order stereorestitution instrument accepting wide angle and super wide angle aerial photography. It is relatively unknown to photogrammetrists in North America. It was tested for the stability of its perspective centers, accuracy of plate measurements, and its suitability for independent model triangulation. Departure of perspective center coordinates from instrument zero position when moved through maximum rotational range amounts to 0.04 mm in x, 0.04 mm in y, and 0.02 mm in z. Base component displacements by" and bz’ needed in relative orientation cause an apparent shift of about 0.03 mm in all three directions. Standard deviations of plate coordinates of 20 grid intersections used in perspective center stability tests are:

σx′ = ±0.007 mm, σy′ = ±0.007 mm, σx″ = ±0.006 mm, and σy″ = ±0.004 mm.

Independent model triangulation of four separate short strips of a heavily controlled area was adjusted by Schut’s 2nd degree polynomial adjustment. Standard deviations at plate scale are σx = ± 0.012 mm; σy = ± 0.012 mm. The relative accuracy of vertical control points is about 1/8,000 of the flying height.
Some Reflections on Survey Disciplines in the Context of the Present Development and Requirements of Society
Authors: Blachut T. J.
Published: July 2019

Following an exponential function, not only is world population rapidly increasing but so is our knowledge in all fields. This also holds true in the surveying disciplines. Owing to the introduction of photo grammetry, the initial scope of surveying disciplines has been significantly widened and today includes the traditional field of interest as well as the mapping of celestral bodies and precise measurements of a variety of objects and phenomena not connected with the shape and the size of the earth or its surface. This widening of the traditional field of activity occurred, however, before the primary objectives and the responsibility of the surveying disciplines were fulfilled. Only a portion of the earth’s surface has been surveyed and mapped, but what is urgently needed today is a much more detailed and dynamic information system revealing not only the geometric features of the earth, but also its resources and rapidly changing ambient conditions. To meet this requirement, it is important that the scientific and professional community realizes the new situation and takes a more active part, or perhaps even assumes direct leadership, in an effort toward planning strategy for the survival of mankind.
Particularism of Quebec Law Pertaining to Legal Surveys
Authors: Raymond Gérard
Published: July 2019

Quebec law, from the point of view of legal surveys, has a unique character when compared with the legal regimes of other Canadian provinces. This particularism is essentially based on the regime of civil law effective in Quebec and the system of registration of real rights based on the Quebec official cadastre. The distinctive application of the monumentation concept in Quebec law gives a concrete example of this situation.
The Correction of Lens Distortion with Polynomials
Authors: Bujakiewicz Aleksandra
Published: July 2019

This paper presents results of an effort to express known lens distortion values by polynomials. Two polynomials, one expressing radial lens distortion, the other decentering distortion, were used with an increasing number of terms. The effectiveness of these two types of polynomials of various lengths was checked on photographs taken over a test field. Lens distortion data and test field photographs were available for two reseau cameras of different makes.
A Comparison of Precision Alignment Methods
Authors: Chrzanowski Adam , Jarzymowski Andrzej , Kaspar Milan
Published: July 2019

The following four methods of precision alignment surveys have been compared on a 816-m test line:

1) conventional optical alignment with a DKM-3 telescope and movable targets, 2) conventional traversing with forced centering using a closed (loop) traverse, fitted traverse and a narrow triangles method, 3) direct alignment with a collimated He-Ne laser and photoelectric targets, 4) diffraction method employing Fresnel zone gratings, He-Ne laser and photoelectric or visual centerings.

Fourteen alignments of points B and C (Figure 1) on the line A-D were performed in different atmospheric conditions. Measurements of horizontal gradients of temperature indicated that discrepancies of up to 8 mm in the alignment could be expected because of the side refraction effects. Results of the alignments are listed in Tables 1 and 3.

Laser alignments were performed with prototypes of instruments (Figures 5, 6, 8 and 10) that had been designed and constructed at the University of New Brunswick.
Automation in the Production of Nautical Charts
Authors: Evangelatos Timothy V.
Published: July 2019

This paper reviews the present status of automation for the production of charts within the Canadian Hydrographic Service and discusses some of the major problem areas in which there has been limited progress. These include the conversion of graphical data to a digital form, which is a tedious and expensive process, and the difficulty of including the cartographer within the digital process so that his judgment and experience can be utilized.
Environmental Management Mapping for the Canadian North
Authors: Taylor Kenneth G. , Simpson-Lewis Wendy
Published: July 2019

Among the numerous mapping approaches employed by the Lands Directorate of Environment Canada, the Land Use Information Series stands out as an unique information system for environmental and social data from northern Canada. Employing a 1:250 000 topographic base, the maps present spatial data and textual explanations in a one-page atlas format. The map series is prepared for the Department of Indian Affairs and Northern Development for use in the administration of the Territorial Land Use Regulations, and it is widely used by government and industry for regional planning purposes.
The Effect of Ambient Conditions on the Accuracy of the Estimation of Distance and Angle Measurements in Large Geodetic Networks
Authors: Ahmed Fouad A.
Published: July 2019

The change in variances in microwave distance measurements and in angle observations obtained on different terrain and under different meteorological conditions is investigated. The value of reading the wet bulb thermometer plays the main role in determining the accuracy of the refractive index. A simplified formula is derived for the calculation of the standard deviation of the measured distance in ppm at different dry and wet bulb thermometer readings. The formula is applicable to all wet bulb readings above the melting point.

Geodetic triangle misclosure and its variance in three extensive samples were statistically analyzed. The samples were chosen according to the type of terrain covered. It was found that side refraction and deflection of the vertical contaminated the chosen samples and that hypothesis of equal variances in such samples cannot be statistically accepted. Accordingly, relative variances in angle measurements are recommended for consideration for the simultaneous adjustment of large geodetic networks.
Remote Sensing as an Aid to the Inventory and Management of Natural Resources
Authors: Colwell Robert N.
Published: July 2019

An analysis is given of the extent to which modern remote-sensing techniques might be used to facilitate the inventory and management of such renewable natural resources as timber, forage, and agricultural crops and of such nonrenewable resources as minerals and fossil fuels. The first part of the paper seeks to clarify both the terms and the concepts that are applicable to the fast growing field of remote sensing. This is followed by a discussion of the various basic considerations that enter into the acquisition and analysis of remotely sensed data. There is an analysis of both the feasibility and the desirability of using data acquired by LANDSAT and other remote-sensing vehicles in the making of globally uniform inventories of various kinds of natural resources. There follows a tabulation of recent and representative applications and the citing of various references in which additional examples are fully described and well illustrated with remote-sensing imagery. Although the paper may appear to be justifiably optimistic, it concludes with some words of caution on the difficulties that can arise whenever there is an overstatement of remote-sensing capabilities and an understatement of remote-sensing limitations. The numerous specific examples of LANDSAT applications that are given in this paper pertain primarily to work done in Canada and the United States.
Redefinition of National Vertical Geodetic Networks
Authors: Lachapelle Gérard
Published: July 2019

A brief review of uses and applications of vertical control points is presented, followed by a description of national leveling networks, which are based on the 1928 Canadian Vertical Datum. Problems and shortcomings related to these networks are discussed. Plans and preparations for a redefinition of North American vertical geodetic networks by the late 1980s are presented. Benefits of such a redefinition are discussed.
Inertial Surveying Systems — Experience and Prognosis
Authors: Schwarz K. P.
Published: July 2019

Initially, the principle of inertial positioning is introduced and extensive new data from the Ottawa test net are used to discuss the state of the art. Two major problems presently limit the accuracy of the systems used in production work: heading sensitivity and the imperfect knowledge of the anomalous gravity field. An initial analysis of the new data indicates that the first is a software problem rather than a hardware problem. It appears that positioning of points along an L-shaped traverse can be done with the same accuracy as along a straight line. The second problem is assessed in a quantitative manner using simulation software. The impact of future hardware improvements on the accuracy of positioning is studied by simulating the error propagation process.
Gravity Field Approximations Using Inertial Survey Systems
Authors: Schwarz K. P.
Published: July 2019

Inertial survey systems can be used to determine changes in the anomalous gravity vector. The underlying principle and the resulting estimation procedures are discussed in this paper.

The analysis of the measuring procedure shows that the observed quantities are dependent on the second-order gradients of the anomalous potential. Thus, the usual representation by the first-order gradients does not adequately model the measurements. The model proposed in this paper considers theoretical as well as practical requirements.

The estimation of gravity field changes is done by optimal filtering. The time-dependent system of differential equations representing the system errors is augmented by a set of parameters that model the anomalous gravity vector as a position-dependent quantity. This leads to a nonlinear estimation problem. Quasilinearization is discussed as one of the possible solutions. The first-order approximation of this solution is a linear estimation problem and thus can be compared to the filtering methods used in present day systems. Questions of implementation are discussed and some open problems are outlined.
The Meaning of Best Evidence
Authors: Mcewen Alec
Published: July 2019

The requirement for the use of best evidence in the resurvey of property boundaries was formerly stated to be a fundamental legal rule, and it may still be found in some modern statutes. Today, however, the true application of best evidence principles depends less on legal compulsion than on sound professional judgment and the obligation to the client.
History of Jet Photographic Operations for Mapping in Canada
Authors: Zarzycki J. M.
Published: July 2019

During the past 11 years the Surveys and Mapping Branch of the Department of Energy, Mines and Resources has met its small-scale photographic requirements for mapping by contracting for the yearly use of a single Lear Jet aircraft. This program has resulted in the acquisition of almost 350 000 line-miles of high-altitude photography at an average cost per line-mile, which is only one third to one half of the rates that were paid prior to the inception of the program. Contracting expertise has been acquired by the Branch and production experience using jet aircraft has been gained by a number of Canadian air survey contractors.
Marine Navigation with NAVSTAR/Global Positioning System (GPS) Today and in the Future
Authors: Wells David E. , Delikaraoglou Demitris , Vaníč Petr
Published: July 2019

The principles of operation of the NAVSTAR/GPS system are described within the context of the more familiar shore-based radionavigation systems, and of the Transit satellite navigation system. The present GPS satellite constellation of up to six prototype satellites, and the eventual constellation of up to 18 operational satellites are described. Some details of GPS signal structure, receiver operation, and error models are given. Results of our simulations of 1980 GPS marine navigation performance off eastern Canada are presented. These indicate GPS is presently capable of providing 150 m or better real-time positioning for about 11 hours a day in this region. GPS performance in the future is discussed.
Photogrammetric Methods in Transmission Line Projects
Authors: Huegli P. , Leupin M. M.
Published: July 2019

Within the project of high-tension transmission lines, Hydro-Québec measures a traverse along the center line and maps a strip of approximately 500 m at 1:2 500 scale by photogrammetric means. Up to now, the aerotriangulation of the 1:12 000 image scale strips was mainly based on inertial control points, while the center line traverse was not used for photogrammetric control. Because of the limited width of the band to be mapped, these traverse points could be useful.

This paper deals with a study on the influence of the central traverse (used as photogrammetric control) on the accuracy within the 500-m band. For this purpose, tests with simulated and real data were carried out applying a rigorous mathematical model. The results show that the inertial points can practically be left out and that the central traverse with a few additional control points assures sufficient accuracy. With a $ 2 600 (1980) price tag for an inertial point, this procedure results in substantial savings.
Rigorous Determination of Irregular Areas
Authors: Ahmed Fouad A.
Published: July 2019

Calculations connected with the measurements of irregular areas are dealt with. A rigorous mathematical model is introduced to obtain the highest degree of accuracy and a new formula is proposed. The new formula gives a simple and unique solution for determining the area and overcomes the disadvantages encountered when applying Simpson’s rule.
On the Definition of Lens Distortion Reference Data with Odd-Power Polynomials
Authors: Ziemann Hartmut , El-Hakim Sabry F.
Published: July 2019

Odd-power polynomials were determined for all lens distortion reference data ever included in the various editions of the Canadian Specification for Aerial Survey Photography. The degree of polynomials as well as the number of valid digits of the polynomial coefficients were varied in an attempt to best fit the given data. For 15 of the 19 lens types included in the investigation, the maximum deviation between best-fitting polynomial and given data was smaller than or equal to the resolution with which the original data were given. The values for the other four lens types were 1.1, 1.4, 1.3 and 1.7 times that resolution; the last two values apply to lenses no longer in service in Canada. Appended to the paper is Appendix I of the latest edition of the Specification for Aerial Survey Photography listing the polynomials which define lens distortion reference data.
ICAS Specification for Aerial Photography: A Look at their Influence on Manufacturers, Contractors and Users
Authors: Fleming E. A.
Published: July 2019

Aerial photography specifications for small-scale mapping in Canada have been in a process of evolution since they were first issued in 1950. An extensive research program carried out by the National Research Council has determined many of the technical standards that are in use today and the ICAS Specification for Aerial Survey Photography governs all federal photography contracted for by the Interdepartmental Committee on Air Surveys and destined for inclusion in the National Air Photo Library. The latest revision of the Specification has given them wider application by providing for the use of a greater variety of camera focal lengths and filters than are normally considered in topographic mapping. A Manual of Procedures has also been compiled which consolidates the operationally useful information for the production of photography to meet the specifications. To determine the effectiveness of the Specification an analysis of the inspection records for the past five years of small-scale photography contracted under the specifications was made. It was found that those photographic items that are essential to the photogrammetrist (lack of y-parallax, overlap) are very well controlled by this method of defining and enforcing requirements, but other important items which affect but do not noticeably impede the work of the photogrammetrist (errors in exposure and processing) have not been effectively controlled. Other methods should be investigated for achieving improvements in the future.
Some Considerations in the Design of Low Cost Remotely-Piloted Aircraft for Civil Remote Sensing Applications
Authors: Tomlins G. F.
Published: July 2019

Early in 1982, B.C. Research began to evaluate the feasibility, advantages and limitations of using Remotely-Piloted Aircraft (RPA) to acquire aerial photography in environmental applications. Advantages associated with these aircraft include low costs, ease of operation, low noise levels, portability, safety and very low speed-low altitude capability. In the first phase of this program, a three-meter span fixed-wing aircraft was constructed from a commercial model kit and modified to carry a remotely-operated 35 mm camera system. In summer 1982, this system was used to acquire aerial photography in a variety of applications including forestry, pollution detection, wildlife habitat assessment, site mapping, publicity, wildlife inventories and shoreline mapping.

Various operational limitations were encountered including difficulty of navigation and aircraft control, the fragility of the “model” airframe and its limited payload capability. These limitations are being addressed in Phase II of the program, during which a purpose-built airframe is under development, equipped with automatic flight controllers and emergency systems, and employing digitally-encoded radio signals for secure aircraft command. A black-and-white video camera installed in the airframe provides real-time imagery as an aid to navigation and photoframing.