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The hyperspectral method for analyzing the Earth's surface is very effective in solving problems of classification of both objects located on it and the state of these objects (for example, agricultural crops). However, a full-scale hyperspectral analysis is a very expensive job, and the search for ways to reduce the cost of this procedure is quite understandable. The most logical way is to reduce the number of spectral components - classification features - by choosing (or forming from them) the most informative ones. In this paper, to implement it by using neural network technologies is proposed. By an example of processing a 200-channel hyperspectral image, it is shown that reducing the dimension of the feature space using these technologies makes it possible to achieve high-accuracy classification with the accuracy exceeding that obtained by other known methods.

The article presents a complex algorithm for combining hyperspectral and highly detailed panchromatic images. The algorithm includes preliminary procedures for the selection of contours and subsequent alignment of hyperspectral and panchromatic images at the corresponding points of their contours. As a result of precise alignment, the accuracy of spectral separation of objects in hyperspectral images is also increased. The resulting hyperspectral image has a high spectral and spatial resolution. The results of numerical studies confirm the high efficiency of the developed algorithm.

An important task of a modern radar is the study of approaches aimed at creating broadband radar systems (radars) with an adaptive phased antenna array (APAA) and the development of principles for their construction and algorithms for processing broadband signals in radars with an APAA. The main advantage of such approaches is an increase in the resolution of the system, which makes it possible to classify targets better. The article focuses on the issue of adaptive spatial filtering of active interference in a radar using digital multichannel signal processing in the frequency domain.

A method is proposed for fast bandwidth selection of kernel functions in nonparametric probability density estimation of a two-dimensional random variable with independent components. The distribution laws under study belong to the family of single-mode and symmetric probability densities. The possibility of their optimization is justified on the basis of the analysis of the asymptotic expressions of the mean square deviations of the components of a two-dimensional random variable. Each component is characterized by an optimal bandwidth of the kernel functions, which depends on the nonlinear functional of the probability density. Its functional dependence on the antikurtosis coefficient of a one-dimensional random variable is established. The effectiveness of the proposed technique is confirmed by the results of analytical studies.

A comparative analysis is made of the remote spectral indices in investigating changes in vegetation cover in post-agrogenic biogeocenoses of the Bolshezemel’skaya tundra. In agricultural use, meadow biogeocenoses, compared with the surrounding background areas, were characterized by relatively high indices characterizing the moisture and photosynthetic activity of plant phytomass (NDVI, LWCI, NDMI, and B5). To assess the changes in the amount of dead biomass, the PSRI index was used, the values of which were minimal during the period of agricultural use of meadows during their regular mowing. During self-healing succession in post-agrogenic biogeocenoses, the values of spectral indices gradually approach those of the background sections. In the post-agrogenic period, the values of the LWCI, NDMI and NDVI indices gradually decreased in meadow biogeocenoses, and the PSRI and spectral channel B3 values increased. The dynamics of the spectral indices is affected by the changes in the species composition. In the post-agrogenic period in meadow biogeocenoses, seeded cereal grass stand is thinned out, a shrub layer is formed, and species introduced from surrounding communities become dominant and subdominant. The activation of the self-healing succession of tundra vegetation in post-agrogenic biogeocenoses takes place against the backdrop of climate warming. Statistical relationships are determined, which reflect the influence of climatic parameters on changes in spectral indices in post-agrogenic and background biogeocenoses. A decrease in the severity of the climate is accompanied by an increase in the values of spectral indices characterizing the vegetative activity of tundra vegetation. An increase in the amount of precipitation contributes to an increase in the values of the indices reflecting the supply of plants with moisture.

Gas geochemical research as a method of exploring gas hydrates and determining hydrocarbon deposits A wide range of applications of gas geochemical investigation in science and practice and for solving various geological and engineering problems are considered in the paper. The method we developed represents a package of technical solutions for extracting gas from water and sediments, and for determining the following gas components on a gas chromatograph: methane (CH₄), heavy hydrocarbon gases (C₂-C₅), carbon dioxide (CO₂), hydrogen (H₂), helium (He), oxygen (O₂) and nitrogen (N₂). It is shown that hydrocarbon gases and hydrogen are an indicator of the possible presence of hydrocarbon deposits, carbon dioxide - of the presence of intrusive activity, and helium shows the gas flow from deep horizons and the mantle. Based on the data of gas geochemical studies, the amount of gas hydrates in the upper layer of the gas hydrate strata was calculated. The possibility of using gases to clarify the stratification processes in the sea is shown. The important role of combining the gas geochemical method with other methods for searching for oil and gas fields, mapping fault zones, determining their seismic-tectonic activity and other geological studies is noted.

The paper examines drought trends in Turkey due to climate change. Therefore, forecasting periods of drought, which is one of the major negative side effects of climate change, is essential. The authors used data from drought indicators according to the SPEI (Standardized Precipitation and Evotranspiration Index) for the period between 1901 and 2015. Values obtained at intervals of 1, 3, 6 and 12 months. The data was subjected to several statistical tests: the Mann-Kendall test to determine the direction and significance of the trend, the Theil-Sen estimator to assess the trend slope coefficient, and the Pettitt-test to determine the most probable year of change. The period under study was divided into two intervals (1901-1981 and 1982-2015), and their comparison was performed. A GIS program was used to isolate spatial characteristics from the results obtained. It was concluded that Turkey is mainly divided into two zones of drought, most of which is an increase in moisture in the northern regions, while a decrease in moisture is observed in the southern regions. The trend towards dry periods was more significant until 1981, but since 1981 the situation has changed due to the onset of the trend towards excess moisture, with the exception of southeastern Turkey, where the trend towards droughts persisted.

Rural population dynamics and settlement in Guba-Khachmaz economic-geographic region (Azerbaijan) We analyzed the dynamics of growth in the number and share of the rural population of the Guba-Khachmaz economic-geographical region for 1989-2019. As a result of a sociological survey conducted in the villages, the factors influencing the standard of living of the rural population and its demographic development were studied, and a grouping was carried out according to the size and structure of the population. The corresponding tables, maps and graphs have been compiled. As a result of the economic crisis of the early 1990s, which forced people to leave their settlements, there was a negative balance of migration, and the natural increase in the population in rural areas decreased. Due to its favorable geographical position, the region has good reserves of oil and natural gas, favorable conditions for the development of fruit and vegetable growing, grain growing, animal husbandry and food processing enterprises. However, the problems that arose in the transitional, post-Soviet period, associated with the production of agricultural products, the work of processing enterprises, the provision of services to the population, had a negative impact on resettlement and increased the intensity of internal migration. After gaining independence of the Republic of Azerbaijan in 1991, the socio-economic development of the Guba-Khachmaz region, the availability of sufficient jobs and the improvement of the quality of services in accordance with the needs of the population had a positive impact on the population in the region, created conditions for demographic development.

The necessity of developing measures for the regional development of Kyrgyzstan, increasing their economic potential and improving the infrastructure for industrial and social purposes is shown. In this regard, the development and revival of the economy of towns, including small ones, are considered as a priority direction in the implementation of these goals. It was revealed that the small towns of the country, due to the diversity of historical formation, economic-geographical location (EGL) and socio-economic values, differ from each other. Their main problems are the lack of economic assets, the scarcity of the city budget, remoteness from large centers, unemployment, and a decrease in living standards. The necessity of a comprehensive study of the potential and development prospects of small towns has been substantiated; a thorough analysis of their economic and geographical position is considered as the most important. As a result, the individualizing features of the towns under consideration were revealed. For this purpose, an assessment was made of the economic and geographical position of small towns in the southern region of Kyrgyzstan concerning their well-being in transport, industrial, agricultural, recreational, market and innovation relations. The results showed that, the towns in the region follow from 3.8 (Kochkor-Ata) to 2.3 points (Sulukta) according to the degree of EGL by components. To generalize these series, the towns were combined into three groups: with the most advantageous economic and geographical location; with a favorable economic and geographical location; towns with a comparatively favorable economic and geographical position. It was proved that the degree of profitability of the economic and geographical position of small towns in the region does not have a territorial sequence, i.e., it is not determined by the “center-periphery” pattern. The study enables determination the general potential for the development of the urban economy, planning the construction of infrastructure facilities, and revival of the industrial sector of the economy as a city-forming factor.

We investigated the classifications of geographical sciences to find new scientific directions that are not included in any of their existing classifications. A methodology is proposed that combines three concepts: structuralism, trinitarianism and fractality. The paper provides examples of the Trinitarian approach in geography. Several traditional trends in geography have been identified (“constructive geography”, “applied geography”, and “theoretical geography”) that are not reflected in existing classifications. In our research, we found that the existing classifications do not reflect the trends in the development of science. The names for already existing directions are proposed: “encyclopedic geography”, ”world outlook geography”, “inventory geography”, “subject geography”, and “poly-scale geography”. A study and grouping of cognitive functions of geography: monitoring, popularization, relevantization, conceptualization, methodologization, education, expertise, planning, forecasting, and information support of policy has been carried out. Geographic sciences were united in hierarchical triads, inscribed in each other. An overview of the Soviet and Russian practices of combining geographical areas is given. The classification is presented not as a branching tree, but as a scientific research algorithm looped inside a fractal triangle. Difficulties that arise in implementation of this algorithm are indicated. The historically established logic of the development of geography in “switching” the focus of research to various subjects of study: “structure, process and environment” is substantiated. The differences in interpretation and content between Russian and foreign cognitive geography are revealed. The advantages in the development of both directions are indicated and an attempt is made to combine them in a single algorithm. The harmonious coexistence in geography of two ideological formulas (dichotomy and trichotomy) is demonstrated.