THE USE OF AIR PlIOTOGRApHS BY THE ORDNANCE SURVEY

Abstract

During the last year, the Air Survey Section, Field Division, Ordnance Survey, have had many visitors. Most of them have been surprised at what they have seen: some at the fact that we are able to make so much use of air photographs even in the largest scale surveys, and some at the small amount of information we seem able to extract from them. This paper is an attempt to give in some detail the ways in which air photographs are used to solve the problems of the Ordnance Survey, why they are used and their limitations for our purposes.     

AIR SURVEY COMES OF AGE IN THE ORDNANCE SURVEY OF IRELAND: 1965–1986

Since the mid-1960s, the Ordnance Survey of Ireland, whose headquarters are in Dublin, has undergone great technological change. This paper emphasises the photogrammetric aspects of that change and outlines how a sophisticated range of modern equipment is used in the supply of survey data for the Irish Republic.     

IMPROVEMENTS IN REPRODUCTION METHODS OF THE ORDNANCE SURVEY

Abstract

The following six notes describe some of the ways in which reproduction methods of the Ordnance Survey have recently been improved. They have been written by different officersof the Ordnance Survey and Ministry of Supply whose initials appear at the end of each note.     

沙枣泉北山旋扭构造浅析

笔者通过遥感图像解译,在甘肃北山东部沙枣泉北山地区发现一个旋扭构造,根据山脊、水系的弧形转折和块状均一的影纹分别判泽出旋扭构造的旋回带和砥柱,经地面检查,已得到证实。据旋回面特征,确定了徒扭面性质和旋扭方向,进而据砥柱由火山岩组成和断裂分布特征分析了旋扭构造成因。     

A NOTE ON THE TRIGONOMETRICAL SURVEY OF SOUTHERN RHODESIA

Abstract

After the completion of Simms's Geodetic Chain in 1901 and the publication of the results in 1905—Volume iii of the Geodetic Survey of South Africa—nothing further of a geodetic nature was done until 1928 when a short chain was run westwards from Simms's chain, at about latitude 17° 10′, to fix the Copper Queen mining area. The Eastern Circuit was commenced shortly after this; it runs from Salisbury eastwards to the Portuguese Boundary, southwards through Umtali to about latitude 20° and then westwards, joining Simms's chain again to the east of Bulawayo. Another chain running north from Simms's work has been commenced near Bulawayo. The several series are exhibited on the outline map attached.     

THE POST-WAR PROGRAMME OF THE ORDNANCE SURVEY OF GREAT BRITAIN

Abstract

In 1938 the committee to investigate the activities of the Ordnance Survey, presided over by Lord Davidson, issued its final report. One of the terms of reference of this committee was “to review the scales and styles of Ordnance Survey maps placed on sale to the public and to recommend whether any changes are desirable”.     

THE ROLE OF PHOTOGRAMMETRY IN THE NATIONAL MAPPING ACTIVITIES OF THE ORDNANCE SURVEY OF NORTHERN IRELAND

Since 1960, photogrammetry has played a leading role in the acquisition of survey data within the Ordnance Survey of Northern Ireland. The decision to create a digital topographic database for Northern Ireland has changed the philosophy and practice of photogrammetry within the organisation and these changes are discussed in this paper.     

THE USE OF AIRBORNE AUXILIARY DATA IN THE RIGOROUS LEAST SQUARES ADJUSTMENT OF A BLOCK OF AERIAL TRIANGULATION

The problem of incorporating airborne auxiliary data into an aerial triangulation block adjustment is considered. The conclusion is reached that this problem can be most readily solved by the use of a fully rigorous adjustment method. The first order adjustment equations for all types of airborne auxiliary control are developed and the method of incorporating these equations into the block solution is demonstrated. The general computing problems of the aerial triangulation block adjustment are briefly discussed and a method outlined for the incorporation of tie strips, at any angle across the block, into the adjustment without unduly increasing the storage requirements for the solution. The problem of correctly weighting the different types of available data is discussed. The paper concludes with a demonstration of the improved accuracy possible if precise aerial triangulation data are combined with apparently crude absolute airborne data.     

卫星遥感土地利用调查精度研究

根据江苏省土地利用卫星遥感调查的实践,对以陆地卫星TM为主要信息源进行土地利用现状和耕地资源调查的定位、定性和定量精度进行分析研究,对应用卫星遥感进行土地利用调查的可靠性、适用范围和提高精度的方法进行了探讨。