Understanding Chorematic Diagrams: Towards a Taxonomy

Abstract

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Chorematic diagrams are prospective candidates for communicating highly generalised geographic information about a given region of interest. Chorematic diagrams were popularized in France as the graphical artefacts of a specific school of geographic thought established by Roger Brunet, with GIP-RECLUS as his institutional backing. Although many maps were created and a lively debate ensued, only few consolidated cartographic findings were generated and even less were made known to the international scientific community. This article presents a contextualizing review and proposes a cartographic taxonomy aimed at being a first step towards efforts for the automated generation of chorematic diagrams.     

Use of Artificial Neural Networks for Selective Omission in Updating Road Networks

Abstract

An important problem faced by national mapping agencies is frequent map updates. An ideal solution is only updating the large-scale map with other smaller scale maps undergoing automatic updates. This process may involve a series of operators, among which selective omission has received much attention. This study focuses on selective omission in a road network, and the use of an artificial neural network (i.e. a back propagation neural network, BPNN). The use of another type of artificial neural network (i.e. a self-organizing map, SOM) is investigated as a comparison. The use of both neural networks for selective omission is tested on a real-life road network. The use of a BPNN for practical application road updating is also tested. The results of selective omission are evaluated by overall accuracy. It is found that (1) the use of a BPNN can adaptively determine which and how many roads are to be retained at a specific scale, with an overall accuracy above 80%; (2) it may be hard to determine which and how many roads should be retained at a specific scale using an SOM. Therefore, the BPNN is more effective for selective omission in road updating.     

Mapping Everest

Abstract

From its inception in the middle of the 19th century, the Royal Geographical Society (RGS) took a keen interest in the exploration and mapping of the Everest region. This formed an integral part of the many Everest expeditions, some of which had individual surveyors or survey parties attached to them. Many mountaineers took part in this work, particularly those with a scientific background. But it was not until 1961 that a comprehensive map was produced of the Everest region.     

The Conversion of Aerial Photography to Symbolised Maps

Abstract

The use of the aerial photograph as a basis for a topographic map is currently one of the most interesting developments in cartography. A member of the staff of the Army Map Service, who is primarily concerned with investigations into map design, presents some possible lines of development in this field.     

Geodetic grids in authoritative maps – new findings about the origin of the UTM Grid

ABSTRACT

Recent discoveries of Wehrmacht Maps in the Military Archive of the Federal Archive of Germany in Freiburg im Breisgau raised the motivation for further investigations into the history of the internationally employed Universal Transverse Mercator (UTM) projection which actually represents a prerequisite for the global use of Global Positioning System (GPS) – and thus of any type of navigation – instruments. In contrast to the frequently stated opinion that this map projection was first operationally used by U.S. Americans it turned out that presumably the first operational maps with indication of the orthogonal UTM grid were produced by German Wehrmacht officers prior to the post World War (WW) II triumph of this projection. Based on the authors´ recent discoveries this article reveals some hitherto hardly known facts concerning the history of cartography of the 1940s.     

The National Archives and Public Records

Abstract

The article provides an overview of the huge cartographic holdings of The National Archives (TNA). It continues by outlining the procedures by which records are selected for permanent preservation by TNA.     

Visual Abstraction and Stylisation of Maps

Abstract

We explore visual map abstraction for the generation of stylized renderings of 2D map data. We employ techniques that are centred around the concept of shape simplification and graph layout and that allow iterative abstraction of 2D maps. We use data from publicly available sources and show how we can iteratively generate aesthetic renditions of these maps. These renditions do not have the goal to allow for navigation tasks, but instead show the map data in a distorted manner. The techniques used to create these images apply simplification, abstraction/generalisation, and displacement operations to the map elements in varying orders and add stylistic shading to produce aesthetic renditions for print or electronic displays. The degree of abstraction/generalisation can be individually chosen and determines the characteristics of the distorted map: whether components retain their shape, degenerate, or are processed in a manner that the abstraction becomes the focus of the image rather than the underlying map data. The renditions can be further personalized by choosing shading and colours for this shading. Together, the presented techniques allow for playful and creative exploration of aesthetic renditions of 2D map data.     

Tactile cartography: another view of tactile cartographic symbols

Abstract

Building on past research into the efficacy of symbols on tactile maps an attempt is made to synthesise the findings of investigations into tactile mapping. Conclusions regarding the most readable symbols, point, line and area, are given.     

Topographic Maps to Support Courses for Visually Impaired Students

Abstract

This short paper describes an inexpensive method for making topographic maps to support visually impaired students. The maps are mainly for courses in geology and ecology, but maps for walking and other recreational purposes have also been produced. The method is not well suited to reproduction of multiple copies, but work is continuing to investigate replication. The paper also considers the choice of materials, scale (including vertical exaggeration) and optimum methods of labelling to meet the needs of both blind and partially sighted students. The project concentrates on making tactile maps affordable, and shows that these can be effective despite using simple tools and techniques from low cost (sometimes free, scrap) material.     

Mapping the London 2012 Olympics

Abstract

The London 2012 Olympic Games was a true spectacle of sporting achievement. It also provided the impetus for official organisations, news media and individuals to turn the vast amount of data into map form. This paper provides an outline of some of the cartographic highlights (and one or two lowlights) that the Olympics inspired. There were some great maps on view and also some interesting trends emerging, particularly in terms of web maps and web maps used as infographics. In particular, the Dorling cartogram saw widespread use, particularly to map medal tallies by online news media.     

RANGE FINDING WITH A THEODOLITE AND SHORT BASE

Abstract

In survey work connected with Seismic (Geophysical) investigations, the nature of the operations is such that provisional points many miles apart have frequently to be located with a minimum of delay. When no map and no triangulation exists, the range finding method about to be described is very useful. The method can also be recomlnended for reconnaissance and exploration surveys. It was used by one of the R.A. Survey Regiments with success during the war. The essentials are a good theodolite and a steel tape.     

IMPROVING THE PERFORMANCE OF WILD PRECISION THEODOLITES

Abstract

IN the July issue of the Empire Survey Review, vol. ii, no. 13, pp· 424–8, there appeared a review of precise theodolite investigations carried out by the present writers; the original papers were published in the March, 1934, number of the Canadian Journal of Research of the National Research Council, Ottawa. The elaboration of some points which could not be given much space either in the original papers or in the review may be of interest.     

On non-linear low–low SST observation equations for the determination of the geopotential based on an analytical solution

In satellite data analysis, one big advantage of analytical orbit integration, which cannot be overestimated, is missed in the numerical integration approach: spectral analysis or the lumped coefficient concept may be used not only to design efficient algorithms but overall for much better insight into the force-field determination problem. The lumped coefficient concept, considered from a practical point of view, consists of the separation of the observation equation matrix A=BT into the product of two matrices. The matrix T is a very sparse matrix separating into small block-diagonal matrices connecting the harmonic coefficients with the lumped coefficients. The lumped coefficients are nothing other than the amplitudes of trigonometric functions depending on three angular orbital variables; therefore, the matrix N=B ^T B will become for a sufficient length of a data set a diagonal dominant matrix, in the case of an unlimited data string length a strictly diagonal one. Using an analytical solution of high order, the non-linear observation equations for low–low SST range data can be transformed into a form to allow the application of the lumped concept. They are presented here for a second-order solution together with an outline of how to proceed with data analysis in the spectral domain in such a case. The dynamic model presented here provides not only a practical algorithm for the parameter determination but also a simple method for an investigation of some fundamental questions, such as the determination of the range of the subset of geopotential coefficients which can be properly determined by means of SST techniques or the definition of an optimal orbital configuration for particular SST missions. Numerical results have already been obtained and will be published elsewhere. Received: 15 January 1999 / Accepted: 30 November 1999     

ROAD LOCATION IN FOREST COUNTRY

Abstract

THE very interesting article on “Road-surveying in the East” by J. N. List appearing in NO. 6 of the Review suggests that the following notes on the methods of road location used in the Gold Coast may be of interest. These methods enter into considerably more detail than those described by Mr. List and are of proved economic value.     

THE ORTHOMORPHIC PROJECTION OF THE SPHEROID–III

Abstract

In the last instalment we were able to obtain most of the surveyor's projections in common use by applying simple scale conditions to the meridians and parallels. This method of approach naturally suggests that results of some value might be obtained by applying similar conditions to the plane co-ordinate lines. If we do so, we are immediately led to consider curves on the surface known as geodesics, which are the nearest approach to straight lines it is possible to draw on a curved surface. Accordingly, we give some account of these curves for the benefit of surveyors who have not hitherto made their acquaintance.     

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.     

Cartography: Making Sense of Our Worlds

Abstract

One goal of cartographic research is to improve the usefulness of maps. To do so, we must consider the process of spatial knowledge acquisition, the role of maps in that process, and the content of cognitive representations derived. Research from psychology, geography, and other disciplines related to these issues is reviewed. This review is used to suggest potential new directions for research with particular attention to spatial problem solving and geographic instruction. A classroom experiment related to these issues is then described. The experiment highlights some of the implications that a concern for the process of spatial knowledge acquisition will have on questions and methods of cartographic research as well as on the use of maps in geographic instruction. It also provides evidence of independent but interrelated verbal and spatial components of regional images that can be altered by directed map work.     

Problems of mapping a nature reserve: Aberlady Bay LNR and SSSI

Abstract

A new five-colour map of Aberlady Bay Local Nature Reserve and Site of Special Scientific Interest at 1:7,500 scale is published as a loose insert with the June 1993 issue of The Cartographic Journal. This accompanying paper describes the problems of producing the map at minimal cost, considers some of the cartographic issues particular to the site, and provides specification details of the compilation.

Such individual map sheets, which are used for environmental planning, research and teaching, have in the past been produced mainly by universities with the support of conservancy and countryside agencies. Future production costs at universities will inevitably rise although some economies may be possible by the use of digital database methods of cartography.     

On the night errors in astronomical determinations

Summary The discrepancy between precision and accuracy in astronomical determinations is usually explained in two ways: on the one hand by ostensible large refraction anomalies and on the other hand by variable instrumental errors which are systematic over a certain interval of time and which are mainly influenced by temperature.In view of the research of several other persons and the author’s own investigations, the authors are of the opinion that the large night-errors of astronomical determinations are caused by variable, systematic instrumental errors dependent on temperature. The influence of refraction anomalies is estimated to be smaller than 0″.1 for most of the field stations. The possibility of determining the anomalous refraction from the observations by the programme given by Prof. Pavlov and Anderson has also been investigated. The precision of the determination of the anomalous refraction is good as long as no other systematic error working in a similar way is present.The results, which are interpreted as an effect of the anomalous refraction by Pavlov and Sergijenko, could also be interpreted as a systematic instrumental error. It is furthermore maintained thatthe latitude and longitude of a field station can be determined in a few hours of one night if the premisses given in [3, p.68]are kept. It has been deplored that the determination of the azimuth has not been given the necessary attention. It is therefore proposed to intensify the research on this problem. The profession has been called upon to acquaint itself better with the valuable possibilities of astronomical determinations and to apply them in a useful and appropriate manner. At the same time, attention has been called to the possibility of improving astronomical determinations with regard to accuracy as well as effectiveness.