The broad requirements of the geomorphologist for original mapping are reviewed. The extent to which aerial photogrammetry can meet these requirements is exemplified through typical approaches and mapping products in fluvial, coastal and glacial specialisms.
This paper examines the intentions, successes and failures of remarkable Romano-Libyan floodwater farmers who settled the arid Libyan pre-desert and used complexes of walls to manage the occasional floodwater as well as the desert's soils, sediments and biota. The paper presents and analyses a near 'total' data-set on the determinable locational properties of these ancient walls within one wadi -the 10 km long Wadi Umm el-Kharab. The organisation of these wall systems is shown to alter along the wadi according to changes in topographic, geomorphic and hydrological factors, as well as in relation to what are regarded in this paper as design and settlement factors. The organisation of the walls changes at confluences and distinctive topographic features. An analysis of the shape of enclosed areas indicates that the wadi can be divided into three broad sectors, each of which can be identified by differences in the shapes of the areas enclosed by walls. The enclosed shapes, as well as the general properties of the walls themselves do not vary in any simple linear manner along the wadi. Precise field mapping, as well as statistical displays of wall-related data, indicate the presence of similar 'gaps' in both the frequencies of settlement and of walls along the wadi. These gaps are, in part, explicable as the secondary consequences of hypothesised past flood-management problems associated with the confluences within the wadi system. They are also interpreted in this paper as some type of land use or other territorial 'break' created between the ancient community groups who occupied the wadi. This study has demonstrated the existence of distinct 'preferences' in the distances between walls, the areas enclosed between walls, and the thicknesses of walls. Overall, the types of organisation, and presumed functions of walls in this wadi are similar to those established from elsewhere in the Libyan pre-desert, but the balance is different in the Wadi Umm el-Kharab. The emphasis of wall-design in the Wadi Umm elKharab appeared to be upon the containment and management of floodwater, rather than the maximisation of the input of waters to the wadi floor, as deduced elsewhere. The long-term robustness and the environmental sophistication of these wall-systems are evident.
Quantitative assessment of the imperfections in the shape of cooling towers is required to enable strength studies to be carried out. Terrestrial photogrammetric methods are described which provide the initial data by locating the position of surface cracks and depicting the surface by means of ring contours. These serve as a basis for further analysis. Résumé Une description quantitative des défauts de construction des tours de réfrigération est nécessaire pour mener à bien l'étude de leur resistance. On décrit des méthodes de photogrammitrie terrestre permettant de localiser leurs fractures et de décrire leur surface au moyen de sections circulaires. Zusammenfassung Zur Analyse der Belastung von Kühltürmen werden quantitative Angaben über die Deformation des Baukörpers benötigt. Es werden Verfahren der terrestrischen Photogrammetrie beschrieben, womit die geforderten Daten durch Lokalisierung von Rissen an der Oberfläche und Beschreibung der Oberfläche mit Umrisslinien bereitgestellt werden. Diese Angaben dienen als Grundlage für weitere Untersuchungen.
A method of delineating the extent of floods has been devised involving the establishment of flood surfaces and the creation of photogrammetric digital terrain models. These two data sources are combined in a computer aided map production system and comparisons are drawn between the efficacy of different forms of terrain modelling in a floodplain environment. Résumé On a mis au point, en vue de déterminer l'étendue d'innondations, une méthode numérique combinant les notions de surface innondable et de modèle numérique de terrain (MNT); on se pose le problème du choix du MNT dans un environnement de plaine innondable. Zusammenfassung Angabe eines Verfahrens zur Ableitung der Ausdehnung von Überschwemmungen, wobei die Flut‐Oberfläche bestimmt und photogrammetrisch digitale Geländemodelle erzeugt werden. Diese beiden Datenquellen werden in einem rechnergestützten Kartiersystem kombiniert, und es werden Vergleiche bezüglich der Wirksamkeit verschiedener Verfahren der Geländemodellierung in Flussniederungen gezogen.
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