IMPROVED SYSTEMS OF CHAINING FOR LAND AND ENGINEERING SURVEYS. (INCLUDES APPENDIX)

W M THOMPSON
1888 Minutes of the Proceedings of the Institution of Civil Engineers  
OF these improved methods of measurement the first described is t h a t which, after many trials and experiments, has been found to ,give results which approach almost to the accuracy of trigonometrical measurement, and is a system which has been proved most .suitable for the detail work of the City of Sydney. This particular nse of l-chain lengths is the most convenient for working in the heavy traffic of a crowded city. The second system described is superseding all other nzodes of
more » ... zodes of measurement in suburban and country districts-where the lines .are long and there is little or no traffic to interfere with the u6e of long lengths of st,eel bands. Of these two systems the first has had its origin from the neces-4 t y that existed of having some good, quick and reliable method for measuring traverse and working lines in carrying out the detail trigonometrical and sewerage-survey of Sydney. This survey, which has been carried out, in a somewhat similar manner to that of the English ordnance survey, was started on the recolnluendation of the late Mr. W . Clark, M. Inst. C.E., that good and trustworthy detail plans of the city should be prepared, to enable the final works for the disposal of the sewage to be properly designed and constructed. As is well known, in surveys for such purposes as Metropolitan railways, sewerage, &C., where all details in the shape of buildings, existing lines of drains, watercourses, and property boundaries require to be shown with great accuracy, and where in consequence a great number of traverse lines must be laid out and chained, it is essentially necessary that some method should be adopted for the measurement of these lines which will give accurate results, and at the same time be expeditious. In this particular case, where the work as it proceeded was connected with the main trigonometrical stations, and the co-ordinate values of the detail stations were checked by comparison with ,those of t,he main survcy, it was found that the old system of Downloaded by [ University of Liverpool] on [14/09/16].
doi:10.1680/imotp.1888.20932 fatcat:qetse6bcmzbx5mbfug3cll4y7e