ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.262

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThe need for better management of land-related information has for some time been recognised. There is precedence for commissioning books on survey-related topics in that as a result of a resolution at the Cambridge Conference of Commonwealth Surveyors in 1967 Rowton Simpson was asked to write what has become a classic on Land Law and Registration. After the 1971 conference, Peter Dale was asked to write about cadastral surveying within the Commonwealth. In 1985 at the fifth general assembly of the Commonwealth Association of Surveying and Land Economy (CASLE) it was decided that the time for further action had come. As a result, CASLE invited Peter Dale and John McLaughlin to prepare some new material. The paper which is presented here highlights some of the issues which were raised in the preparation of their book which has been titledLand Information Management–An Introduction[1]. Many of the comments that follow were raised in a presentation at the 1987 Conference of Commonwealth Surveyors.

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.263

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThe Republic of Trinidad and Tobago (commonly referred to as Trinidad), is at the southern end of the Caribbean island chain, from which it is geologically distinct, since it lies on the continental shelf of South America in close proximity to Venezuela (Figs 1,2). The joint population is about 1·3 million, of whom all but some 50000 live in Trinidad, which at 4830 sq km is much larger than Tobago (300 sq km). Trinidad was a Spanish possession for three centuries before being taken over by the British in 1797: Tobago, by contrast, was not colonised by Spain. It has a most varied history, being ruled at various times by France, Holland and Britain, by whom it was finally recaptured in 1803. The two islands formed a combined colony in 1889 and, still linked, became independent in 1962.

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.269

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractOne of the main characteristics of the Nigerian geodetic network is that it was observed or measured at different points in time starting from the early years of this century with instruments of varying precision. There is the need to improve the quality and strength of the network by re-observing selected lines and angles with modern and more precise instruments, incorporating additional measurements into the system and deleting some observations which do not contribute positively to the over-all accuracy of the network. The implementation of the above operations calls for the use of a sequential adjustment technique. The theory of such a procedure suitable for the recursive adjustment of the Nigerian geodetic network is presented.

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.279

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractThe University of Nottingham has been holding annual survey camps in and around the town of Llangollen in North Wales for nearly 50 years. The hilly nature of the site, the friendly farmers who allow access to their land, and the considerable comforts offered by local hotels at out-of-season prices combine to make Llangollen an ideal site for survey‘camp’. For the first 30 years, the Llangollen survey camps consisted of a topographic task supplemented by an invar base measurement in catenary, and its expansion into a small triangulation scheme. With the advent of EDM and the increasing prominence of surveying at Nottingham, the University acquired a substantial number of high precision instruments. As a result, the task of students is largely based on the provision of horizontal and vertical control, carried out with high accuracy theodolites and EDM instruments, with data almost exclusively processed on interactive micro-computers. Topography and basic surveying are the tasks of another (1st Year) survey camp, with Llangollen devoted exclusively to 3rd Year and M.Sc. students.

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.287

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

AbstractA cascade method of instrumental drift correction to gravimetric data which ensures flexibility of field procedure is presented. The method strikes a compromise between the requirements of a least squares adjustment and the inadequacy of a reference drift curve method of drift removal from data obtained in complicated field procedure. The basic principle is that when all observations in a day are referred to the same time origin during a day's work, repeat observations at the same station after drift correction should be equal. The underlying assumption is that the drift of the instrument is a linear function of time over a short time interval. The method requires that measurements should be done in loops and that observations terminating the outermost loop must either be made at the same station or at different stations whose absolute gravity values are known. Linear drift corrections are then carried out from one loop to another in a cascade manner. A test of the model was made using the data of the Primary Gravity Network of Nigeria. The results of the drift determinations with the cascade method compare favourably with those obtained with the least squares method. The major advantages of the cascade model are summarized. It is further deduced that the cascade model can be used to determine drift corrections in similar surveys where instruments other than the gravimeters are used

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.295

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.303

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.304

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.305

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1988.29.228.306

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor