SOME SUGGESTIONS FOR SPEEDING UP WORK ON TOPOGRAPHICAL SURVEYS

Abstract

A Few notes will now be given on the subject of triangulation on which practically all the methods already outlined depend. If we have a triangulation ready for us on which to base our work, so much the better; but, if not, we must make every effort to carry one through either from our own measured base or from any existing points on the edge of our work. For reconnaissance survey, such a triangulation must be carried out with the greatest expedition; even if all refinements are sacrificed to speed, it is extraordinary how small the errors will be found to be when a more rigid triangulation is made. Any unorthodox method such as carrying through with a resected point or with an astronomical azimuth may be adopted. A bush will often make a good point to observe to, also piles of bushes with a flag on a reed or stick.     

HIGHWAY TRANSITION CURVE DESIGN

Abstract

Uneven Values of ?. It will have been noticed that the deviation angle ? 48°00′ of the previous example lent itself to a solution having spiral lengths ls, and length of circular arc lc both on exact 25-ft. or quarter-chain lengths, so that if the entrance origin is arranged to be on an exact 25-ft. subchainage all the other peg-points will be on exact subchainages also. In the case of a new road across open country this can in most casesbe arranged after a little practice, especially if one works the survey and the new alignment by co-ordinates.     

UNITS OF LENGTH AND THEIR RELATION TO AREAS IN CADASTRAL SURVEYS

Abstract

Brought up as we are in the British Empire in a world of difficult weights and measures, we come to regard them as inevitably complex and laborious, and only when we come into direct contact with professional and business men of foreign nations is it brought home to us how pathetically foolishwe are in sticking to systems of mensuration that have not resulted from deliberate thought but have evolved from the vagaries of mensuration in history. At the commencement of our instruction in arithmetic we are informed (to quote Workman's text-book) that “when we put down a list of the number of inches that make a foot, the number of feet that make a yard, and the number of yards that make a mile, we get what is called a Table of Long Measure. Similar tables are needed for other measures. The following tables must be learnt thoroughly by heart. They are all the measures which are really needed, though a great many more are in use and will be mentioned later.” Here follows, without a word of apology, a page of historical antiquities in the shape of our tables, each one a self-contained entity, seemingly priding itself on having no connexion whatever with any other.     

OpenStreetMap data quality enrichment through awareness raising and collective action tools—experiences from a European project

ABSTRACT

Nowadays, several research projects show interest in employing volunteered geographic information (VGI) to improve their systems through using up-to-date and detailed data. The European project CAP4Access is one of the successful examples of such international-wide research projects that aims to improve the accessibility of people with restricted mobility using crowdsourced data. In this project, OpenStreetMap (OSM) is used to extend OpenRouteService, a well-known routing platform. However, a basic challenge that this project tackled was the incompleteness of OSM data with regards to certain information that is required for wheelchair accessibility (e.g. sidewalk information, kerb data, etc.). In this article, we present the results of initial assessment of sidewalk data in OSM at the beginning of the project as well as our approach in awareness raising and using tools for tagging accessibility data into OSM database for enriching the sidewalk data completeness. Several experiments have been carried out in different European cities, and discussion on the results of the experiments as well as the lessons learned are provided. The lessons learned provide recommendations that help in organizing better mapping party events in the future. We conclude by reporting on how and to what extent the OSM sidewalk data completeness in these study areas have benefited from the mapping parties by the end of the project.     

LEAST-SQUARE ADJUSTMENTS OF TRIANGULATION DIRECTIONS VERSUS ANGLES

Abstract

IT has been assumed in the past that because angles for triangulation are usually observed by the direction method, therefore it must be more correct theoretically to perform the least-square adjustments by directions rather than by angles. It is fairly obvious that an adjustment of the same figure by directions will not give the same result as an adjustment by angles: the unknowns in each case are different and the number of directions is usually about 25 per cent. greater than the number of angles for the same figure. Strictly, the least square method is only applicable to observations from which all systematic errors have been eliminated, and in which the remaining errors are truly accidental. It is generally safe to assume that most survey errOlS consist of a random and a systematic part. Rarely, if ever, is it possible to state that all systematic error has been eliminated, strive how we may to take all precautions against it.     

A PLEA FOR THE EXPANSION OF THE SCOPE OF THE DOMINION AND COLONIAL SURVEY DEPARTMENTS

Abstract

In the remarks which follow, the word “scope” will have the meaning given in the Concise Oxford Dictionary—“Sweep or reach or sphere of observation or action, extent to which it is permissible or possible to range, opportunity, outlet, vent”. Another good definition is “field of action”. The object of the paper is to show that greater efficiency will be obtained if all types of survey work in a country, except possibly railway surveys, are done under the supervision of, or by the staff of, a Survey Department of wider scope than is normal.     

REPORTS. THE YEAR 1934 IN CEYLON

Abstract

The Ceylon Survey Department is gradually returning to its normal activities after the period of depression. The programme of work is again being increased as the demand for survey work grows with returning prosperity in the Colony. The Survey Department Training Classes have been reopened for training new recruits to fill the vacancies in the upper and lower grades which have been left unfilled during the retrenchments. It takes a year, however, to train a subordinate office: and two years to train a probationary Assistant Superintendent, Including one year at Cambridge. Recruiting is consequently rather. a slow process, and it will be some years before the Department is again at full strength, as there are now 27 vacancies in the Field Staff and 34 in the Office Staff to be filled, out of a total of 705.     

Cartography in the GIS age

Abstract

At the end of the 1980s, the computer experts who had been in the vanguard of cartographic development lost their position due to the fact that computers became democratised. This may be ascribed to the 'Macintosh' effect. This in turn led cartographic companies back to the core of their professional know-how: it is cartographers themselves who now develop the scope of their profession, utilising all the resources provided by the new computer technology. But, if cartographers want to keep playing a major role in the geographic information arena, they have to determine and develop the specific elements of their discipline: if technology mobilizes all forces to the detriment of theory, then the discipline progressively weakens and ends in being swallowed by another discipline.

It is the cartographers' task to transform the spatial information from its verbal, social and numerical form into visual form for visual thinking; this visualisation provides for cognitive functions, communication functions, decision support functions and social functions. In order for maps to perform these functions cartographers should continue, now with digital tools, to safeguard data quality by monitoring the compilation stage during which they have to see to it that the heterogeneous datasets in databases will be made comparable, both from a geometrical, semantical, updatedness and completeness point of view. This main aspect of the cartographer's job can be called its engineering part. The other main aspect will remain the map design part, that leads to proper communication of the spatial information. Both aspects will remain the cartographer's domain if he/she succeeds in providing a theoretical basis for his/her work.     

RECONNAISSANCE MAPPING FROM TRIMETROGON AIR PHOTOGRAPHS IN THE ANGLO-EGYPTIAN SUDAN

Abstract

Trimetrogon air surveys have been used extensively in the United States and Canada but seem to have had less favour on this side of the Atlantic in spite of the fact that large areas over here were photographed in this way during the last war. The Sudan is a very large country, but not a rich one; and up to the present it has not been able to undertake its own aerial photography. The gift of a very large number of American trimetrogon photographs covering half the country was therefore very welcome, and it seemed worth our while to see what could be done with them in spite of the known disadvantages of this type of photography for anything but small scale mapping. The methods of planimetric mapping from these photographs developed in the United States were expressly designed to be as simple as possible and to be capable of division into a number of easy tasks which could be performed by any educated person after a short course of training. Nevertheless we felt that they could be simplified a great deal more if the problem was approached from a different angle, particularly in view of the very high standard of flying which was apparent in the photographs covering the Sudan.     

TESTING A THEODOLITE FOR ACCURACY

Abstract

When a theodolite is used to measure an angle, the result will be subjected to certain instrumental and personal errors which affect the measurement. Such errors may be accidental or systematic. Those of the former type, which follow no law and which may with equal probability occur at any graduation, are more easily eliminated, since, if a very large number of readings is taken, it is probable that the errors will cancel out and that the mean will approximate very closely to the correct figure. Systematic errors are usually due to instrumental defects and rnay be expressed as a function of the reading itself; it is the object of the manufacturer to eliminate these as far as possible, since cancellation by reiteration or by repetition is not to be expected wholly.     

ROAD-SURVEYING IN THE EAST

Abstract

The title of this article is wide and generous, covering the art of road-surveying under every condition of climate from snow to tropical heat and in all types of country from moist forest to arid desert, from wooded mountains to barren rocks. But there is one feature that is common to all these conditions. Skilled supervision is at a minimum, and semi-skilled subordinates do the work. This has naturally had an influence on the quality and extent of the surveying carried out as a preliminary to the making of new roads. Some junior official, frequently from a subordinate service, is detailed for a survey, and he is expected to locate the final centre-line of the road on the ground and to produce plans, sections and a complete construction estimate. How then does he set about it? He probably has a small-scale map—in India, if he is lucky, a good, contoured, one-inch-to-the-mile map; and there are almost certain to be village tracks, either cart-tracks or man-tracks. Further, there will be certain obligatory points on the route, a pass to be crossed, a river to be bridged in a particular neighbourhood where it has well-defined banks, a town or village to be served, and so on.     

Digital Earth: a new challenge and new vision

ABSTRACT

Digital Earth has seen great progress during the last 19 years. When it entered into the era of big data, Digital Earth developed into a new stage, namely one characterized by ‘Big Earth Data’, confronting new challenges and opportunities. In this paper we give an overview of the development of Digital Earth by summarizing research achievements and marking the milestones of Digital Earth’s development. Then, the opportunities and challenges that Big Earth Data faces are discussed. As a data-intensive scientific research approach, Big Earth Data provides a new vision and methodology to Earth sciences, and the paper identifies the advantages of Big Earth Data to scientific research, especially in knowledge discovery and global change research. We believe that Big Earth Data will advance and promote the development of Digital Earth.     

Reasserting Design Relevance in Cartography: Some Concepts

Abstract

Cartographers have always been concerned about the appearance of maps and how the display marries form with function. An appreciation of map design and the aesthetic underpins our fascination with how each and every mark works to create a display with a specific purpose. Yet debates about what constitutes design and what value it has in map-making persist. This is particularly acute in the modern map-making era as new tools, technology, data and approaches make map-making a simpler process in some respects, yet make designing high-quality maps difficult to master in others. In the first part of a two-part paper, we explore what we mean by map design and how we might evaluate it and apply it in a practical sense. We consider the value of aesthetics and also discuss the role of art in cartography taking account of some recent debates that we feel bring meaning to how we think about design. Our intent here is to reassert some of the key ideas about map design in cartography and to provide a reference for the second part of the paper where we present the results of a survey of cartographers. The survey was used to identify a collection of maps that exhibit excellence in design which we will showcase as examplars.     

THE ORTHOMORPHIC PROJECTION OF THE SPHEROID—II

Abstract

The reader will play this round better if he remembers to bring the bag of clubs provided in the last instalment. On the assumption that he will do so, we proceed straight to the first tee without further explanation or recapitulation.     

CADASTRAL AIR SURVEY

Abstract

I Hope Dr Wolff's interesting article will stimulate to action some of those who have not given sufficient attention to air survey as a method of mapping or planning those areas which lend themselves to that method. At the same time, whether so many of us are as conservative as the author appears to think is a matter for doubt, and moreover we do not all look upon air survey as an “innovation”. As Dr Wolff writes from Palestine he might be interested to know that as the second British Officer to take up field survey work in the War in 1915—Major (now Brigadier) Winterbotham being the first—I was one of the earliest in my profession to study, and to assist in the development of, air survey. In 1915 our unit in the 3rd Army was the first to make use of air photographs for the production of a regular series of trench maps. There are consequently few surveyors more interested in the method. I have watched the progress of the science and the work of the Air Survey Committee with continued interest and have used air methods whenever these have been possible or suitable. On my last visit to Paris I tried my hand at plotting with a new instrument at the Service Géographique and was much impressed by the work that was being done.     

Coupling sensor observation services and web processing services for online geoprocessing in water dam monitoring

ABSTRACT

Novel sensor technologies are rapidly emerging. They enable a monitoring and modelling of our environment in a level of detail that was not possible a few years ago. However, while the raw data produced by these sensors are useful to get a first overview, it usually needs to be post-processed and integrated with other data or models in different applications. In this paper, we present an approach for integrating several geoprocessing components in the TaMIS water dam monitoring system developed with the Wupperverband, a regional waterbody authority in Germany. The approach relies upon the OGC Web Processing Service and is tightly coupled with Sensor Observation Service instances running at the Wupperverband. Besides implementing the standardized XML-based interface, lightweight REST APIs have been developed to ease the integration with thin Web clients and other Web-based components. Using this standards-based approach, new processing facilities can be easily integrated and coupled with different observation data sources.     

Producing Tactile Maps Using New Inkjet Technology: an Introduction

Abstract

Three common methods for producing tactile maps are mixed media, microcapsule paper and thermoform. This paper describes a new method for producing tactile diagrams using piezoelectric inkjet. To produce diagrams a photo-curing acrylic polymer ink is repeatedly printed onto a thermoplastic substrate and exposed to ultraviolet light which bonds the ink to the substrate and cures it solid. The speed and precision of the process means maps with fine, easily discriminated tactile features will be readily available to users. The new process will facilitate further psychological, psychophysical and cartographic research.     

The British Cartographic Society Annual Report

Abstract

There is hidden within early texts information, which if analysed, can be used to increase our understanding of early cartography. This paper considers the possible relevance of the Venerable Bede's concept of Britannia to cartography, his comprehension of the original data, and, why that may have affected his view of Britannia. The information also provides us with an opportunity to construct an alternative for the lost portion of the Tabula Peutingeriana, at least as it pertains to Britain, and to consider the residual areas.