Physiographic area classification, landscape mapping, satellite observations
Introduction. Physiographic area classification has the longer history of development than landscape mapping. Yet the landscape science specifically and landscape mapping in particular have provided physiographic area classification with greater objectivity and intensionality of characteristics of chosen regions. On the basis of this, a number of geographers have concluded that physiographic area classification is the element of regional landscape science (Nikolaev, 1979, Isachenko, 1991 and others) and it has been exhausted as the independent school.
The researches on physiographic area classification were held with the most intensity at the second part of XX century. Respectable studies devoted to area classification of the USSR in general and the Ukraine republic in particular appeared practically simultaneously in 1968. More than 200 geographers were engaged in interuniversity researches on natural and economic-geographic area classification for agriculture then. A great number of regional publications were made, but landscape structure of chosen regions was not always clearly explained in them.
Physiographic area classification, classification of landscapes and landscape mapping. Physiographic area classification, classification of landscapes and landscape mapping are traditional types of geographic modeling, and even a single regional landscape research is impossible without them. Area division and classification as qualificatory operations are different in their methodological premises, though they are closely interconnected and can amplify each other. Area classification is based on principal framework of division of the general into different parts (or integration of the general from its parts). In the process of area classification the ranking of geosystems is created, it shows their hierarchy according to the degree of complexity (necessary system diversity) of landscape arrangement and spatial-temporal dimension. Generally accepted taxonomic unit of area classification (from top downward) are physiographic country, province, region etc. Classification of landscapes from its side presupposes the search of general, identical in multitude of peer individual geosystems, their typification. The system of typological taxonomic units (class of landscapes, type of landscapes) that matches it, assumes the transition (from top downward) from the most general and substantial characteristics of landscape objects to more and more particular and specified. In short, the formula of area classification is "the general - the particular", the formula of classification is "the individual-the typical". According to V.B.Sochava (1978), classification of geochorae (heterogenous geosystems) is situated at the heart of area classification, and the classification of geomers (relatively homogeneous geosystems).
Moreover, there is a certain correlation between taxonomic units of typological classification and units of physiographic area classification (Sochava, 1978, Nikolaev, 1979, Isachenko, 1985). Each landscape individuum and types, clans of landscapes are geographically localized and bear up their location and comprehensive regional geosystems. As a consequence, outside of physiographic area classification, without reference to it, it is virtually impossible to develop the classification of landscapes. Specifically, if we refer to vast territories encompassing several physiographic countries, natural zones and provinces.
From the other side, landscape and geographical classification cannot be imagined without parallel typological mapping, i.e. creation of three dimensional landscape models. Classification and typological mapping are different sides of the same coin. The first provides the information about the structure, genesis and other substantial (substantive) properties of geosystems, the other one provides the facts about their territorial organization, spatial differentiation and vicinity. The evidence suggests that only in a process of landscape mapping the creation of relatively complete regional classification is possible. This classification becomes the basis of the legend of a map. Thus as a systematic landscape model as a spatial one are integrated in the map.
Mapping as a rule precedes typological mapping and classification of landscapes. At this phase of research it is made "from top downward", by the way of differentiation of large natural subcompartments into smaller, subordinate. However, after that, area classification is considered again on the basis of a made map, the accuracy of it is improved by integration of types - clans of landscapes into paragenetically holistic geosystems of regional dimensions. As a result, physiographic area classification, typological mapping and classification of landscapes combine into a single process of regional landscape research. Nowadays area classification cannot be implemented without support of the small scale landscape mapping materials and regional satellite images ("Satellite landscape science", "The landscapes of Asian steppes", Nikolaev, 1993, 1999).
Cartometrical analysis. The materials of landscape typological maps cartometry are easily transformed into the system of mathematico-statistical indicators which quantitatively characterize the regional landscape structure from different sides. The measures of landscape differentiation are used more than others (subarea classification, pattern structure) of regions, landscape heterogeneity (diversity), landscape vicinity, organized structure and some other measures (Nikolaev, 1979). A.S.Viktorov (1986) compiled the most thorough status report of such indicators.
The rates of territorial landscape contingence (paragenetic vicinity) are used successfully in finding the most important region forming combination of landscape types. In total, physiographic area classification completed on the basis of landscapes, i.e. "bottom-upwards" is becoming really geosystematic, central (connectional). In this regard the principle of structural and genetical integrity is realized versus the principle of homogeneity of regional subcompartments previously widely applied.
Cartographo-mathematical landscape structure research objectifies the process of physiographic area classification. In this case maps and schemes of area classification which used to contain little information are enriched by prolific landscape content and relevant quantitative indicators. Alongside with that, the considered measures have a definite practical interest. They are applicable for quantitative estimate of the complexity degree of landscape area design in regional planning, design of highways, oil and gas pipelines, hydro land reclaiming facilities, recreational attractiveness etc.
Satellite observations, physiographic area classification, landscape science. The Earth space observation has given new possibilities in modernization of techniques of physiographic area classification. Satellite observation of the Earth surface bearing the considerable visibility successfully model not only landscapes but larger natural geosystems which have the level of physiographic regions, provinces, areas and even countries i.e. the traditional objects of physiographic area classification.
In many cases one can research several physiographic provinces and junction of two or three physiographic countries simultaneously with the help of only one medium- or small-scale satellite image.
Physiographic area classification based on satellite images is made by several integrated methods. The main of them are similar to those which are used in area classification based on typological landscape map. From one side, it is integration of local landscape structures into comprehensive regions, from the other; it is differentiation of large natural unities into subordinate geosystems, forming their internal structure. The mentioned approaches oncoming by their nature are defined as area classification from "bottom" and "top". The landscape structural principle is the basis of both approaches as the landscape structure of regions is seen as the main criterion of their indication and individualization which can be based on satellite images.
The other trend in physiographic area classification based on remote materials presupposes the search the most important natural frontiers subject to geologic-geomorphologic, bioclimatic and any other factors of landscape differentiation with the help of satellite images. The most strongly marked factors are frontiers of lineal structure types - lineal orotectonic frontiers of morphostructire of different order. As it was established the most physiographic regions (countries, areas, provinces, regions) and individual landscapes are closely connected with relevant different order morphostructure. Fractality (subdivision) of landscape crust is sufficient to tectonic subdivision of the Earth crust substantially.
The search and decryption of lineal structure is a crucial component of physiographic area classification. As a rule, one or another linear structure identified on an image is a natural frontier at the same time that separates one physiographic subcompartment from the others. In different sides from the lineal structures the types of satellite images patterns differ greatly. Thus frontiers of such kind are emphasized. As we range physiographic regions (from landscape to physiographic country), it is advisable to range linear structures according to their importance in landscape crust differentiation.
In distinction from orotectonic frontiers indication of bioclimatic - zonal and subzonal frontiers is more troublesome with the help of satellite images. As a rule, they are quite gradual, and often they are represented by transition bands of ecotonal character. Not only subzones but even zones such as forest tundra, forest steppe, semidesert etc could be given as the examples. In decryption of zonal (subzonal) frontiers the density of phototone and colour scheme of satellite images of automorphic landscapes are analyzed in the first place. Different indirect decryptional factors are used at the same time. The degree of area wooding, the peculiarities of agricultural use can serve as the mentioned factors. Wooded lands and cultivated agricultural lands are easily observed from the satellite images. At the plains depending on degree of area wooding the frontiers (gradual transition) between tundra and forest tundra, forest tundra and taiga, taiga and mixed forest and depending on the degree of ploughing - between forest steppe and steppe, steppe and semi desert is precisely traced.
The materials of satellite observations of the Earth surface acknowledge the famous aspect about the great genetic and structural diversity of natural frontiers. The part of them, mainly orotectonic determine the clearly specified discreteness (fractality) of landscape crust. The others, mainly bioclimatic, are reflection of landscape continuum.
Remote sensing of the Earth from space has become the powerful factor of theoretical and methodical regional landscape science progress. The materials of satellite observations have one of the first places among the scientific landscape geographic models according to merit. They provide as structural as evolutionally-dynamical researches with valuable information. Moreover they have become the fundamental basis of regional landscape monitoring due to increasing anthropogenic burden on the environment. Satellite images demonstrate the multilevel hierarchy of natural and natural-anthropogenic geosystems, multi-staged structuring (fractality) of landscape area. They are powerful evidence in favour of acceptance of absolute objectivity of landscape and geosystems of other measures in this property.
Conclusion. The main issue of area classification is often seen in insufficient knowledge of many areas of landmasses that leads to schematization of borders and characteristics. Yet area classification should be a scheme, a skilful choice of degree of generalization. Though scientific approach implies the repetition of experiments, unification of methods, standardization of data collection and presentation of results, however the problem of the general and the particular will always remain in the classification of geosystems.
Computerization has the technical and the conceptual aspect, the latest is the most difficult for acquisition. The qualitative geographical analysis with engaging of highly skilled specialists as Kalinik Gerenchuk was is vital in order to be certain in educts.
It is important not to exscind the previous findings with the development of new opportunities. The issues of physiographic area classification and landscape mapping are absorption of new techniques and technologies with cautious attitude towards the traditional techniques and above all towards the results of traditional researches.
Viktorov A.S. The pattern of landscape. M.:Misl Publishers. 1986.
Isachenko A.G. The landscapes of the USSR. L.,. 1985.
Isachenko A.G. The landscape science and physiographic area classification. M., 1979.
Nikolaev V.A. The space landscape science. M., 1993.
Nikolaev V.A. The landscapes of Asian steppes. M., 1999.
Sochava V.B. The introduction into the geosystems studies. Novosibirsk, 1978.
Physiographic area classification of the USSR. Edited by doctor N.A.Gvozdetsky. M., 1968.
Physiographic area classification of the Ukraine republic. Edited by doctor V.P. Popov, doctor A.M. Marinich, assistant professor A.I. Lanko. Kiev, 1968.