Procedures for woody vegetation surveys in the Kazgail rural council area,Kordofan, Sudan

Efforts to reforest parts of the Kordofan Province of Sudan are receiving support from international development agencies. These efforts include planning and implementing reforestation activities that require the collection of natural resources and socioeconomic data, and the preparation of base maps. A combination of remote sensing, geographic information system and global positioning systems procedures are used in this study to meet these requirements.

Remote sensing techniques were used to provide base maps and to guide the compilation of vegetation resources maps. These techniques provided a rapid and efficient method for documenting available resources. Pocket‐sized global positioning system units were used to establish the location of field data collected for mapping and resource analysis. A microcomputer data management system tabulated and displayed the field data. The resulting system for data analysis, management, and planning has been adopted for the mapping and inventory of the Gum Belt of Sudan.     

Noise-signal index threshold: a new noise-reduction technique for generation of reference spectra and efficient hyperspectral image classification

Reference spectra of terrestrial targets are usually collected using field spectro-radiometers for mineral abundance mapping and target detection. These spectra often have noise that masks characteristic absorption and reflection features and affects the efficiency of material mapping. This work aims at obtaining an empirical technique for reduction of high-frequency noise from field spectra. The proposed noise correction technique uses a ‘normalized’ measure R_n , where R_n  = (L_n  ? F_n )/L_n for each band (n) calculated from field and laboratory spectra of test material, with F_n and L_n being the depth of the absorption feature in field and laboratory spectra, respectively. On the basis of the assumption of the constancy of this ratio in neighbouring bands, an empirical algorithm that approximates the ratio R_n of a noisy band to the corrected ratio of an adjacent band is used to obtain the noise-corrected field spectra. The classification accuracy increases significantly when noise reduced field spectra are used as reference spectra.     

Soil resource assessment and mapping using remote sensing and GIS

In this study digital image processing for physiographic analysis and soil resource mapping of Solani watershed was carried out using satellite remote sensing data and GIS. Digital image processing of satellite data facilitated in accurately delineating and identifying various soil mapping units. The physiography of the study area is mainly influenced by denudational and colluvial processes in the upper part and by sedimentation processes in the lower part. Topography of the land and nature of parent material along with the time factor seemed to have played a vital role in the genesis of soils. Majority of the mapping units are Typic Haplustepts with Entisols and Inceptisols being the major soil orders. The soils of the Siwalik hills experiences severe erosion, which prevents the maturation of soil profile. The present study demonstrated that satellite remote sensing and GIS is a valuable tool for physiographic analysis and soil resource mapping.     

Assessing soil salinity using WorldView-2 multispectral images in Timpaki,Crete, Greece

Salinization is one of the major soil degradation threats occurring worldwide. This study evaluates the feasibility of operational surface soil salinity mapping based on state-of-the-art Earth Observation (EO) products captured by sensors on-board WorldView-2 (WV2) and Landsat 8 satellites. The proposed methods are tested in Timpaki, south-central Crete,Greece, where brackish water irrigation puts soil health at risk of soil salinization. In all cases, EO products are calibrated against soil samples collected from bare soil locations. Results indicate a moderate correlation of observed EC_e values with the investigated remote sensing parameters. Regarding sensitivity to saline soil, the yellow band displays higher values. Comparison between methods used in the literature shows that those developed specifically for soil salinity, and especially index S5, perform better. The proposed ‘detection index’ and 3D PCA transformation methodology perform reasonably well in detecting areas with high EC_e values and provide a simple and effective operational alternative for saline topsoil detection and mapping.     

Molodensky potential telluroid based on a minimum-distance map. Case study: the quasi-geoid of East Germany in the World Geodetic Datum 2000

 A potential-type Molodensky telluroid based upon a minimum-distance mapping is derived. With respect to a reference potential of Somigliana–Pizzetti type which relates to the World Geodetic Datum 2000, it is shown that a point-wise minimum-distance mapping of the topographical surface of the Earth onto the telluroid surface, constrained to the gauge W(P)=u(p), leads to a system of four nonlinear normal equations. These normal equations are solved by a fast Newton–Raphson iteration. Received: 7 February 2000 / Accepted: 23 October 2001     

Transformation of coordinates using piecewise conformal mapping

A multiresolution-like algorithm for piecewise conformal mapping is presented. The algorithm is based on partitioning the complex plane into convex polygons, defining appropriate window functions for these polygons, and finding a conformal mapping for each polygon. The window functions are used to glue the pieces together into a single mapping. An application of this algorithm to determine a transformation from the Estonian coordinate system of L-EST92 into the respective system L-EST97, is presentedAcknowledgments.This work has been supported by Estonian Science Foundation grant nr. 5037. The author also thanks the Estonian Land Board, especially U. Mets and L. Tamme for their help in preparing the data, and the reviewers for valuable suggestions.     

UNCONTROLLED MAPPING FROM AIR PHOTOGRAPHS

Abstract

Many methods of mapping from air photographs “without control” have been proposed from time to time. Usually this means having no control, or very little, on the ground. The following paper describes some experiences of mapping without controlling the photographs inter se, a suggestion which must rank as improper with a Photogrammetrist.     

MORPHOMETRIC MAPS OF GLACIAL SURFACE TOPOGRAPHY

Several procedures for mapping the topography of the surface of an alpine glacier are described: slope angle mapping, mapping of dissection depths, trend surface analysis, and the mapping of residuals. Methodological problems addressed include determination of class intervals for mapping, data transformation techniques, and an entire range of issues connected with proper sampling methods. The purpose is to demonstrate how the mapping of multiple indicators of ice-surface relief increases the flexibility of cartographic methods for identifying underlying geomorphological processes. Translated from: Vestnik Leningradskogo Universiteta, 1984, No. 6, pp. 43-48.     

EXPERIENCE IN COMPILING LARGE-SCALE MAPS OF EROSION-PRONE AREAS

Specific criteria used in the compilation of large-scale maps of erosion-prone areas are defined and evaluated for tracts of land representing a number of different agricultural cover types. Formulas are derived which facilitate the mapping of such areas based on such readily observable morphometric characteristics as slope length and steepness. Translated by Edward Torrey, Alexandria, VA 22308 from: Vestnik Moskovskogo Universiteta, geografiya, 1988, No. 5, pp. 25-31.     

MAPS OF COMBUSTIBLE FOREST MATERIALS

An article devoted to applied forest-fire mapping outlines principles for the compilation of maps depicting “raw materials” for such fires. Various types and densities of vegetation cover are classified in terms of combustibility, i.e., according to the intensity of burning expected once they are fully exposed to flames. These maps are used in conjunction with weather data and forecasts to predict and combat the spread of fire across an area. Particular attention is devoted to identification and mapping of “basic conductors” of combustion–layers of forest litter and mossypeaty vegetation along which a forest fire normally spreads. Translated from: Geografiya i prirodnyye resursy, 1987, No. 3, pp. 138-144.     

ECOLOGICAL-GEOGRAPHIC MAPPING: CONCEPTS,METHODS, AND TECHNOLOGY

Another paper in a series of articles on ecological-geographic mapping (see for example, Mapping Sciences and Remote Sensing, Vol. 31, No. 3, July-September 1994, pp. 185-220) focuses on outlining a concise typology of such maps and providing a brief history of their emergence during the 1970s and 1980s. A subsequent section is devoted to methods and technology used in the compilation of ecological-geographic maps, particularly the multiple variants of data organization, processing, and cartographic representation that can be factored into research design. Translated by Edward Torrey, Alexandria, VA 22308 from: Geografiya i prirodnyye resursy, 1995, No. 4, pp. 10-18.     

ECOLOGICAL ASSESSMENT AND MAPPING FOR BALANCED REGIONAL DEVELOPMENT

A Russian geographer summarizes the results of a comprehensive study of modern landscapes and the mapping of diverse ecological situations. The procedure involves the development of a system of criteria and indices for the assessment of the properties of the environment, which provide a sound basis for comprehensive ecological mapping. The importance of an ecological assessment in the mapping of environmental problems and situations in support of the stable and balanced development of regions is demonstrated. Translated by Edward Torrey, Alexandria, VA from: Izvestiya Akademiya Nauk, seriya geograficheskaya, 1999, No. 1, pp. 81-87.     

CURRENT PROBLEMS IN OCEAN MAPPING

The author, in a review of papers presented at the First All-Union Conference on the Geography and Mapping of the Oceans, outlines the present status and current trends of marine cartography in the USSR. Issues warranting increased attention include development of a systems approach for the mapping of marine ecosystems; improvement of methods and principles for the mapping of coastal zones, bottom relief, and shelf topography; and accelerated production of economic/resource maps of the oceans. Work now underway on a comprehensive, multi-volume A tlas of the Oceans reflects a Soviet concern with these issues. Translated from: Geodeziya i kartografiya, 1984, No. 12, pp. 38-42.     

AN ATLAS OF CMEA MEMBER NATIONS

General problems of complex atlas mapping—selection of scales and indices for mapping, standardization of legends, establishment of appropriate levels of generalization, etc.—are addressed using the first comprehensive economic atlas of CMEA member countries as an example. The Atlas itself contains general overview maps of economic linkages of CMEA member nationa with the world economy, maps devoted to economic transactions and patterns within the CMEA as a whole, and general economic maps of the individual member nations. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1985, No. 4, pp. 3-6.     

Evaluating Hyperspectral Imager for the Coastal Ocean (HICO) data for seagrass mapping in Indian River Lagoon,FL

Differentiation between benthic habitats, particularly seagrass and macroalgae, using satellite data is complicated because of water column effects plus the presence of chlorophyll-a in both seagrass and algae that result in similar spectral patterns. Hyperspectral imager for the coastal ocean data over the Indian River Lagoon, Florida, USA, was used to develop two benthic classification models, Slope_RED and Slope_NIR. Their performance was compared with iterative self-organizing data analysis technique and spectral angle mapping classification methods. The slope models provided greater overall accuracies (63–64%) and were able to distinguish between seagrass and macroalgae substrates more accurately compared to the results obtained using the other classifications methods.     

THE MAPPING OF FLOODPLAIN VEGETATION ON A LANDSCAPE BASIS

A “genetic” principle for the identification of morphological units on a floodplain landscape is applied to the mapping of vegetation and, more specifically, to a study of the spatial distribution of forest vegetation within the Ob' River floodplain. Aspects of the problem which are discussed include the identification and ranking of floodplain units and their components and appropriate scales for image interpretation and mapping. The principles and procedures outlined are applicable to the mapping of other floodplains. Translated by Edward Torrey, Alexandria, VA 22308 from: Geografiya i prirodnyye resursy, 1989, No. 2, pp. 78–84.     

SOIL-GEOBOTANICAL REGIONALIZATION FROM REMOTE SENSING IMAGERY

A multiscalar approach to mapping soil-vegetation regions from remote sensing imagery is outlined, using the West Siberian Lowland as a study area. At an initial stage small-scale space imagery is used to identify extensive soil-vegetation regions which extend across nearly the entire Lowland. Subsequent analysis focuses on identification and mapping of increasingly smaller units. The dominant criteria used for image interpretation and regionalization vary at each particular level of analysis, changing from vegetation structure and density at the smallest scales to soil “hydromorphism” (waterlogging) and topographic affiliations for intermediate- and large-scale units. Hydromorphic indicators are stressed as most important overall. Translated from: Distantsionnyye issledovaniya rel'yefa Sibiri, A. L. Yanshin and V. N. Sharapov, eds. Novosibirsk: Nauka, 1985, pp. 51-58.     

Understanding spatial variations of malaria in Vietnam using remotely sensed data integrated into GIS and machine learning classifiers

Abstract

This study examines the potentials of remotely sensed data, GIS and some machine learning classifiers and ensemble techniques in the investigation of the non-linear relationship between malaria occurrences and socio-physical conditions in the Dak Nong province of Viet Nam. Accuracy assessment was determined with Receiver Operating Characteristic (ROC) curve and pair t-test. The results showed that the area under ROC of Random Subspace ensemble model performed better than the other models based on statistical indicators. Comparing pair t-test with Area Under Curve values showed a slight difference of about 1%. Therefore ensemble techniques had significantly improved the performance of the base classifier. However, the performances might vary according to geographic locations. It is concluded that the machine learning classifiers combined with remotely sensed data and GIS is promising for malaria vulnerability mapping, and the derived maps can be used as a fundamental basis for programmes on spatial disease control.     

The generalized Mollweide projection of the biaxial ellipsoid

Summary The standard Mollweide projection of the sphere S _R ² which is of type pseudocylindrical — equiareal is generalized to the biaxial ellipsoid E _A,B ² .Within the class of pseudocylindrical mapping equations (1.8) of E _A,B ² (semimajor axis A, semiminor axis B) it is shown by solving the general eigenvalue problem (Tissot analysis) that only equiareal mappings, no conformal mappings exist. The mapping equations (2.1) which generalize those from S _R ² to E _A,B ² lead under the equiareal postulate to a generalized Kepler equation (2.21) which is solved by Newton iteration, for instance (Table 1). Two variants of the ellipsoidal Mollweide projection in particular (2.16), (2.17) versus (2.19), (2.20) are presented which guarantee that parallel circles (coordinate lines of constant ellipsoidal latitude) are mapped onto straight lines in the plane while meridians (coordinate lines of constant ellipsoidal longitude) are mapped onto ellipses of variable axes. The theorem collects the basic results. Six computer graphical examples illustrate the first pseudocylindrical map projection of E _A,B ² of generalized Mollweide type.