The Oblique Zenithal Equidistant Projection

Abstract

The idea of constructing an equidistant map centred on Glasgow originated as a school project. The amount of calculation required meant that it was necessary to use a computer to calculate the co-ordinates for the projection on a 15° graticule. Subsequently it was decided to write a program to instruct another computer, equipped with a graph plotter, to plot the same graticule automatically. The basic mathematical constructions and the procedure for programming the computer for automatic plotting are fully explained.     

An Evaluation of the Use of Grid Squares in Computerised Choropleth Maps

Abstract

There are numerous computer programs to produce choropleth maps and some work has also been published on the use of a grid matrix as a way of dividing an area into discrete units. The purpose of this paper is to combine the two approaches and evaluate the suitability of using a network of grid cells, each containing a representative value of the variable being mapped, as a way of producing choropleth maps on a computer.     

CONVENTIONS AND GENERALIZED FORMULAE FOR THE ASTRONOMICAL TRIANGLE

Abstract

In the October 1953 issue of this Review (E.S.R. xii, 90, 174), Mr. J. G. Freislich has written of the difficulties of a southern hemisphere computer attempting to use astronomical formulae from a textbook prepared for use in the northern hemisphere. He proposes a solution in which different conventions are adopted in the two hemispheres, leading to different formulae for the two cases, a solution which the present writer does not favour.     

TRAVERSE REDUCTION WITH AN ELECTRONIC DIGITAL COMPUTER

Abstract

The article describes work carried out by the authors on the Manchester Universal Digital Computer at Manchester University. The general characteristics of the computer are discussed. The requirements for traverse reduction for Ordnance Survey work are summarised, with the help of a specific example. The technique required to present the details of a traverse to a computer for reduction is then described, and some details of the operation of the programme are given. The article is concluded with some details of the time taken to carry out the reduction, and remarks about special features of computer design which would have proved advantageous for this work.     

FMC cameras,high resolution films and very large scale mapping

Abstract

Very large scale mapping (1/250) was experimented on the basis of FMC camera, high resolution film and total station surveying.

The future attractive combination of precision photogrammetry and personal computer assisted terrestrial surveying was investigated from the point of view of accuracy, time effectiveness and total procedures control.     

MAPIT: A Computer Program for Production of Flow Maps,Dot Maps and Graduated Symbol Maps

Abstract

This paper describes some results of an attempt to design and to write a general purpose computer program which can be used to produce quality maps of discrete data by the person who has had no training in computer programming. In the first section, the variety of the maps this program can produce is illustrated; in the second section, some of the principles involved in such map production are discussed; in the third section, the input arrangements for using the program are described and, finally, the role of such programs in teaching and research in the years ahead is discussed.     

A DIRECT METHOD OF TRANSFORMING RECTANGULAR COORDINATES FROM THE CASSINI PROJECTION TO THE GAUSS CONFORMAL PROJECTION

Abstract

6. Further Expansions.—Equations (4.3) and (5.5) enable a computer to transform coordinates from the Cassini projection to the Gauss projection without recourse to geographical coordinates. If applied to one or two points, no doubt these equations would be quite satisfactory; but if applied to 100,000 points their use would be laborious and it would be difficult to adapt them to machine computing.     

SOME NOTES ON COMPUTING

Abstract

Probably the most important matter connected with computing is checking. Far more time is wasted by an incorrect result which has been passed as correct by the checker than by any other fault in computing. It is not necessary that a computer should always be perfectly accurate, but it is necessary that the method of checking used should always detect his errors. If the computer is sure that his accidental errors will be picked up he is relieved of anxiety and his work will be quicker and eventually more accurate for that reason.     

Mapping Cyberspace: Visualizing,Analysing and Exploring Virtual Worlds

Abstract

With the development of computer technologies such as the Internet and reality, the notion of cyberspace has been emerging and it has been increasingly studied by researchers in various disciplines involving the computer sciences, sociology, geography, and cartography. Cybermaps, as special maps for cyberspace, have been produced and used as a tool for understanding various aspects of cyberspace virtual worlds. Virtual worlds can be distinguished in many ways from the physical world we live in. Because of these distinctions, it is a big challenge for cartographers to offer some clarification. This paper addressed various mapping issues such as visualizing, analysing and exploring cyberspace from different aspects.     

An Agricultural Atlas of Scotland

Abstract

An account is given of the theoretical and practical problems of producing a series of maps from available statistical data. The source material and in particular the disparities in area of the statistical units are treated in detail. A simple program was developed for use with the KDF9 computer with line printer output, and eventually this was used to provide a compilation for drawing rather than a finished product.     

MINOR TRIANGULATION

Abstract

When Clarke had written finis to his account of the Principal Triangulation he and O'Farrell (his famous chief computer) framed those simple methods of computation which were to be characteristic of the work of the “tertiary computers”. The tertiary triangulation, resting upon an adjusted primary and a rather poor-class secondary, covered the country at distances of a little over a mile between points. Points were chosen not so much for visibility as for convenience of chaining.     

A MACHINE METHOD OF RESECTION

Abstract

With the modern calculating machine in easy reach of every computer, the problem of determining the position of an occupied point from which direction observations have been made to three or more known points has become quite simple. The method outlined below is quite elegant in form and exceedingly simple on the machine. Let A, B, C be the three points whose co-ordinates (X₁Y₁), (X₂Y₂), (X₃Y₃) are known, and let (XY) be the co-ordinates of the point P which we wish to fix.     

MINOR TRIANGULATION ON THE TRANSVERSE MERCATOR PROJECTION

Abstract

In a previous article in this Review, the writer endeavoured to show that chains of minor triangulation could be adjusted by plane rectangular co-ordinates ignoring the spherical form of the earth with little loss of accuracy, provided that the two ends were held fixed in position. It was demonstrated that the plane co-ordinates produced by the rigorous adjustment between the fixed starting and closing sides, differ by only a comparatively small amount from the projection co-ordinates produced by a rigorous adjustment on the Transverse Mercator projection. The saving in time when computing by plane co-ordinates as opposed to rigorous computation on the projection by any method will be apparent to any computer with experience of both methods.     

Numerically Controlled Methods of Automatic Plotting and Draughting

Abstract

The equipment available for numerically controlled plotting and draughting is reviewed and certain devices described in some detail. Several systems suited to the digitising of cartographic material exist, while the available plotters may be classified broadly into three categories—those derived from surveying and photogrammetric practice, those associated with computer technology and a group designed substantially for cartographic applications. Finally the various input and output devices associated with cartographic digitising are discussed with special emphasis on their storage capacity, speed of operation and economy.     

Parallelizing maximum likelihood classification on computer cluster and graphics processing unit for supervised image classification

ABSTRACT

Supervised image classification has been widely utilized in a variety of remote sensing applications. When large volume of satellite imagery data and aerial photos are increasingly available, high-performance image processing solutions are required to handle large scale of data. This paper introduces how maximum likelihood classification approach is parallelized for implementation on a computer cluster and a graphics processing unit to achieve high performance when processing big imagery data. The solution is scalable and satisfies the need of change detection, object identification, and exploratory analysis on large-scale high-resolution imagery data in remote sensing applications.     

The applications of high resolution satellite data for coastal management and planning in a pacific coral Island

Abstract

Coastal Tropism is a worldwide phenomenon. It induces urgent needs for observation inventories and management of coastal environment, mainly in developing countries.

High resolution satellite data may solve some aspects of the problems. Three examples based upon the potential use of shrimp aquaculture sites in tropical salt marshes, the biotopes mapping in coral reef environments for biologic stock assessments and the characterization and quantification of evolutive stages of coral platforms, are developed. All three are relative to the same tropical Pacific Island with respect, for the first and second examples, to actual needs for the management of mangroves and coral reefs and for the third, to a scientific approach related to evolutive theory of reefs platforms in lagoons.

Methodology and results based upon digital image processing and computer assisted photointerpretation are exposed.

New trends in digital processing and associated digital cartography are listed.     

Measuring the Coastline from Maps: A Study of the Scottish Mainland

Abstract

While attempting to devise a methodology for the assessment of the impact of planning decisions on the coastline of Scotland, it became apparent that a means of mapping information concerning the coastline and coastal zone was necessary. This meant that the maps had to be capable of being produced in bulk, they should be easy to alter and produce at different scales and with different information. It was therefore decided to investigate the potential of computational techniques to produce the required maps. This was performed by employing a d-Mac digitising table to generate the required coordinates and by processing the information on the University of Aberdeen's ICL system 4/70 computer, the output being on drum plotter.     

A SIMPLIFIED ANALYTICAL METHOD FOR THE ADJUSTMENT OF AERIAL TRIANGULATION

Abstract

This method, which has been used in connection with Wild A5 and A6 stereoplotting machines, was developed in an endeavour to retain as many as possible of the advantages of the analytical method without incurring the corresponding disadvantage of excessively lengthy computation. It is capable of being quickly learnt by even an inexperienced computer, and adequate checks on the accuracy of the numerical work are easily applied where not automatically provided. It has the advantage over the graphical method formerly used, that no control point is accepted as more reliable than another, equal weight being given to all, and an indication of the relative reliability of the individual control points is furnished by the table of residual errors obtained.     

Toward a unified theoretical framework for photogrammetry

ABSTRACT

The objective of photogrammetry is to extract information from imagery. With the increasing interaction of sensing and computing technologies, the fundamentals of photogrammetry have undergone an evolutionary change in the past several decades. Numerous theoretical progresses and practical applications have been reported from traditionally different but related multiple disciplines, including computer vision, photogrammetry, computer graphics, pattern recognition, remote sensing and machine learning. This has gradually extended the boundary of traditional photogrammetry in both theory and practice. This paper introduces a new, holistic theoretical framework to describe various photogrammetric tasks and solutions. Under this framework, photogrammetry is generally regarded as a reversed imaging process formulated as a unified optimization problem. Depending on the variables to be determined through optimization, photogrammetric tasks are mostly divided into image space tasks, image-object space tasks and object space tasks, each being a special case of the general formulation. This paper presents representative solution approaches for each task. With this effort, we intend to advocate an imminent and necessary paradigm change in both research and learning of photogrammetry.