POPULATION CENSUS WITH THE AID OF AERIAL PHOTOGRAPHS: AN EXPERIMENT IN THE CITY OF LEEDS

This study shows how aerial photographs can be of value in a population census. The census and the enumeration district maps were used initially to obtain population data and the housing stock was derived from the aerial photographs. From these the population densities were determined of a number of sample enumeration districts containing a single type of house. Another set of enumeration districts was selected and the housing stock again derived from the aerial photographs. By considering the type and quantity of housing stock and the population density of each housing type, the population figures were estimated for each enumeration district. The values of these population estimates were then compared with the values recorded in the census. The overall population estimate had an error of only 2%, but the estimates for some of the individual enumeration districts showed greater errors. These errors are assessed and analysed and some suggestions are made to improve the methodology used in this study.     

应用航空摄影资料编制高山峡谷地区正射影像图

本文阐述了利用既有比例尺为1:4.5万和1:3.5万的航摄像片及1:5万成图的航测外业控制成果,经内业空中三角测量加密定向点,采用解析测图-正射投影系统,编制成318幅1:1万高山峡谷地区的正射影像图的技术。经过检查,成图质量达到了技术设计标准,满足土地资源调查制图精度要求。     

AERIAL AND SPACE PHOTOGRAPHS IN THE STUDY OF GEOSYSTEM DYNAMICS

A Siberian geographer explores real and potential applications of remote sensing imagery in research on geosystem dynamics. Four different methodological approaches to the analysis of geosystem dynamics are identified and described: comparison of heterochronous and seasonal imagery, geosystem forecasting and reconstruction based on image analysis, determination of current state and extant geosystem trends, analysis of linkages and interactions among geosystem components. Translated by Edward Torrey, Alexandria, VA 22308 from: Geografiya i prirodnyye resursy, 1992, No. 4, pp. 140-146.     

AN EXPERIMENT IN ADJUSTMENTS, USING SUPER-WIDE ANGLE PHOTOGRAPHY TAKEN FOR TOPOGRAPHIC MAPPING

The paper describes an experiment using three different methods for the production of control for topographic mapping from super-wide angle photography. The result showed that aerial triangulation by independent models observed on a Wild A9 would show economic advantages in cartographic effort required, control requirements, and accuracy attained in contouring. The experiment also indicated that great benefit in heighting accuracy is derived from the addition of tie strips flown at right angles to the main photographic cover at a suitable interval and that heights supplied by airborne profile recorder are not sufficiently accurate to be economically advantageous where close interval contours are a requirement.     

IDENTIFYING AND ASSESSING PROBLEM AREAS IN SOIL EROSION SURVEYS USING AERIAL PHOTOGRAPHS

Gully erosion has for many years been a problem in Rhodesia1s Tribal Trust Lands. This paper describes how Soil Conservation Service staff, with no previous ground knowledge of these areas, used good quality 1/25,000 scale aerial photographs to measure the extent of the gully erosion and to pinpoint erosion “black spots.” This enabled quick and reliable estimates of the cost of reclamation work to be made without the need for time-consuming field survey. The survey method discussed is capable of wide application wherever gully erosion occurs and needs to be brought under control.     

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.     

TEXTURE OF FOREST COMMUNITIES ON AERIAL PHOTOGRAPHS

The authors discuss a method by which the image characteristics of forest vegetation can be used to determine various valuational characteristics of forest stands through the combination of air photo interpretation and ground surveys at selected training sites. Construction of curves showing changes in image texture and tone occurring at different stages in the growth cycle of a pine forest community are used to estimate the age of a forest stand, and through known relationships between age and other stand characteristics incorporated into yield tables, to approximate such valuational characteristics as mean diameter, mean height, and stand volume. Translated from: Distantsionnyye issledovaniya rel'yefa Sibiri, A. L. Yanshin and V. N. Sharanov, eds. Novosibirsk, Nauka, 1985, pp. 73-78.     

THE YELL AERIAL TRIANGULATION EXPERIMENT

The paper considers the experimental comparison of a method of aerial triangulation in previous experimental use by Eden and the standard Ordnance Survey method using stereocomparators. The accuracy of plan fixations was high by both methods, with Eden's method providing the better result. A comparison is made of the times taken under experimental conditions for both methods.     

DETERMINING RELATIVE ORIENTATION ANGLES OF OBLIQUE AERIAL PHOTOGRAPHS

The author feels that the present methods for the determination of relative orientation elements on aerial photographs are not generally effective. She has conducted an experimental investigation and obtained a high degree of accuracy in the determination of these elements using a new algorithm and successive approximation. The author presents a general solution to the problem of relative orientation where approximate values of unknowns are no longer needed. Translated from: Geodeziya i kartografiya, 1983, No. 11, pp. 29-32.     

A PROJECTION METHOD OF MAPPING FROM AIR PHOTOGRAPHS

Abstract

An instrument was previously described in the Transactions of the Royal Society of S. Africa for the setting of pairs of photographs, taken from air stations, in correspondence; that is, in the same relative positions that the camera occupied in space at the moments of exposure. The principle of the instrument may be recalled.     

AN EXPERIMENT IN SYSTEMATIZING THE CARTOGRAPHIC IMAGES OF GEOMORPHOLOGICAL FEATURES

The authors attempt to identify and standardize the cartographic symbols (“images”) used to represent a variety of specific geomorphological features. A large number of cartographic representations of landform features found on geological-geomorphological maps are classified in terms of their basic pattern/configuration and the level of complexity within each major pattern type. It is argued that the pattern or configuration of a cartographic symbol used to represent a geomorphological feature should represent the spatial structure of that feature with sufficient reliability to serve as a key to an understanding of its genesis. Translated from: Geomorfologiya, 1987, No. 2, pp. 62-66.     

THE INTERPRETATION AND MAPPING OF VEGETATION AND OTHER GROUND SURFACE FEATURES FROM AIR PHOTOGRAPHS OF MOUNTAINOUS AREAS IN NORTH WALES

The paper describes work undertaken in North Wales in 1967 and 1968 in which panchromatic and colour air photographs were used in the mapping of vegetation and in the study of other ground surface features. The problems of relating a priori classification schemes to the categories distinguished by air photo-interpretation are discussed and the case stated for developing classifications which enable more benefit to be derived from the advantages of air photo-ecology.