ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.2

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractIn 1986 the Ordnance Survey was awarded a contract by Transmanche-Link (TML) to produce a unique grid for use in the design and construction of the Channel Tunnel. L'lnstitut Geographique National (IGN) France made all the observations in France and provided an independent computation of the complete network [4]. In 1987 both IGN and OS had single frequency GPS receivers and TML requested IGN to strengthen the 1986 network by including GPS observations. Nortech were contracted by IGN to observe across the Channel with dual-frequency TI 4100 GPS sets whilst OS were to observe with Trimble receivers in England and IGN in France using their Sercel sets.

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.3

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractPoints of maximum and minimum elevations together with points of curvature inflection are chosen in the field when executing levelling nets. Since these points are definite and crucial in defining the slope of the ground surface, they are used in a mathematical model for contouring. This method proves to be more rigorous than the usual linear interpolation. It also reduces the amount of field work required, since only those crucial points which define the ground shape are considered and, accordingly, the number of levelling points is reduced.

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.15

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractAfter a brief review of the existing methods of horizontal curve ranging, a new technique, the‘Optimum Point Method’(OPM) is developed and its practical applications discussed. The basic setting out technique involves the use of radial angles and chord lengths or radial distances. The theoretical principles and equations are based on circular curve theories and direction cosines.The new technique which has several advantages over existing ones aims at ranging out the horizontal curve from a specific vantage point referred to as the Optimum Point (OP). Any other vantage point can be chosen for setting out purposes depending on field conditions and economic considerations. All points within the curve vicinity are referred to a local coordinate system which has the OP as its origin.

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.22

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractDeveloping nations which hold to a concept of private ownership or administration of land require survey and cadastral systems capable of supporting modern definition and information needs. Fiji is such a nation. This paper outlines the procedures followed in the definition and adjustment of the 1986 Fiji Geodetic Datum drawing particular attention to the need to balance such factors as cost, use of historical triangulation data, use of Doppler and other modern survey data, and the desire to provide the foundation for a multipurpose, integrated, survey and cadastral system suited to both present and future land tenure and land information needs. It describes the practical problems addressed in the Datum definition, comments upon the merging of the various data sets, and describes the final adjustment.

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.33

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.43

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.45

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.48

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1989.30.231.i

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor