Delineating ravinous areas on aerial photographs and satellite Imagery-A comparative study

Extensive areas along Yamuna, Chambal and their tributaries in Uttar Pradesh, Rajasthan and Madhya Pradesh have been severely eroded forming ravines of various depths. These areas offer great potential for the development of agriculture and forestry after reclamation. In order that they are reclaimed and managed properly, precise data on their nature and extent are needed. Morphometric analysis of ravine lands along Chambal and Kunwari rivers near Bhind, Madhya Presdesh has been carried out using 1:25,000 scale aerial photographs. Landsat imagery for the same area has been interpreted to find out the relative recognition of morphometric units earlier interpreted on air photos. It was observed that while aerial photographs provide data regarding depth, width, slope and frequency distribution of ravines at a greater detail, Landsat imagery helps in delineation of broad reclamative groupings which would be useful for Large Area Planning (LAP). A multistage approach involving the use of both air photos and satellite imagery seems to be the possible answer for preparing a Ravine Map of India.     

Capability of photointerpretation methods for mapping of Vindhyan and Deccan Trap terrain — A case study from Jhalawar area,Rajasthan

Geological mapping of the Vindhyan and Deccan Trap terrain around Jhalawar was accomplished by aerial photointerpretation with limited field checks in parts, by conventional field mapping for part of the area and also by interpretation of LANDSAT imagery. A comparative assessment of the data producing capability and accuracy of these methods is made from the case study. Major geological formations comprising Semri, Kaimur, Rewa and Bhander groups of Vindhyan supergroup, Deccan Trap and recent fluvial sediments are equally interpretable from all three level (i.e. ground, air and space) surveillance data. All the members and units are mappable on air photos and on ground but not on the LANSAT imagery. It is difficult to plot all the flows and flow units of Deccan Trap on a topographic base map during conventional field mapping but these are more or less separable on aerial photos. Structural trends are decipherable by photointerpretation but lineaments are well depicted on LANDSAT imagery. Physical and petrological characters of rocks can, however, only be studied in situ and by laboratory analysis of samples. Aerial photointerpretation techniques can be applied for geological mapping of Vindhyan and Deccan Trap terrain with high degree of confidence and reasonable accurate maps can be generated. LANDSAT imagery are useful for generation of small scale reconnalssance and lineament pattern maps. The best system of mapping such terrain would be photointerpretation with limited field check and collection of essential groundtruth and specimens for laboratory analysis along selected traverses thus minimising the time and cost of survey.     

LANDSAT (MSS) imagery interpretation: A new perspective tool aiding regional hydromorphic mapping for groundwater exploration

With the advent of Remote Sensing via Satellites, specially the LANDSAT providing a synoptic overview of our Earth, a powerful new tool aiding in regional terrain analysis for natural resources surveys is now available to earth scientistis. Many significant earth features identifiable on LANDSAT images help to update regional surveys. Sequential coverage is an added advantage. Based on terrain analysis using LANDSAT imagery, and utilising the principles of visual interpretation to develop satellite photo-analytical keys highlighting landforms, drainage features and the like it is possible to delineate hydromorphic units for groundwater studies on a regional scale. The paper highlights the utility of LANDSAT imagery interpretation in small scale hydromorphic mapping for groundwater studies by citing examples from North and Central India. The advantage of conjunctive use of satellite, aircraft ann ground data in enhancing survey results is mentioned. The known and expected hydrologic conditions in the different hydromorphic units mapped have been given. The study approach is relatively new in India, and can be very useful in planning regional groundwater exploration programmes. The method is speedy and economical. Possibilities of similar studies in a host of other areas of survey such as flood studies, erosion surveys add a new dimension to the study of our Earth.     

Terrain analysis of Panna District,Bundelkhand, Madhya Pradesh,using LANDSAT imagery

Visual interpretation of LANDSAT imagery in bands 6 and 7 covering Panna district, Bundelkhand, Madhya Pradesh was carried out for terrain analysis and present land use. The physiographic units viz. hills and hill ranges, escarpments, ridges, table-land, pediment, piedmont plain and sub-units of second order were identified and delineated using inter pretation elements. Area of each unit and sub-unit is calculated and presented in the table showing extent, tone, texture, shape and land use. Land use in relation to physiographic units is also described in the paper and shown in the form of small scale map. Visual interpretation technique helps in broad terrain analysis on scale 1:1 million. This information could be used for making a rapid resource inventory.     

Physiographic analysis for small scale soil and landuse mapping of Mewat area,Haryana, using LANDSAT imagery

Visual interpretation of LANDSAT imagery of 1∶250,000 scale (band 5 and 7) and 1∶1 M (FCC) covering 1611 km² in Mewat area, Haryana was carried out for delineating the physiographic units. The physiographic units viz. hills, piedmont plain, intermontane basin and Yamuna alluvial plain were identified and delineated using interpretation elements. Soils and land use in relation to the physiographic units were studied during the field visit and are described in the paper.     

Reclamative grouping of ravines using Cartosat-1 PAN stereo data

Information on the depth and bed width of ravines (network of gullies) at large scales is critical for their reclamation and management. Hitherto such information has been generated from aerial photographs and space borne stereo images with medium to coarse ‘z’ – axis resolution. The present study, aims at demonstrating the potential of Cartosat ?1 (an Indian Earth observations satellite) stereo images with 2.5 m spatial resolution in deriving morphometric information on ravines for their reclamative grouping. The study area is a part of Jhansi and Hamirpur districts of Uttar Pradesh, northern India. The approach involves acquiring precise ground control points using Differential GPS (DGPS), triangulation, DEM extraction and generation of ortho image as well as anaglyphs for stereo viewing. The depth and bed width of ravines were measured in the field for validation. A comparison with field observations reveal that the bed width of ravines and depth can be measured successfully with Carto-1 stereo data. The anaglyph data was used to delineate various categories of ravines based on their depth and bed width. Results indicate that the Cartosat-1 stereo images are quite suitable for delineation of three categories of ravines, namely shallow (<3 m deep and <18 m bed width), medium deep (3–9 m deep and >18 m bed width) and deep (>9 m deep) which are important for their reclamation.     

Geology of the area around Katta,sindhudurg district,Maharashtra. Based on aerospace data

Geological studies of the area around Katta, in the southern part of the Ratnagiri District of Maharashtra, were carried out with the help of visual remote sensing techniques using LANDSAT imageries on 1:250,000 scale and aerial photographs on 1:60,000 scale. The major stratigraphic units represented in the area under study are the Archean Complex, Kaladgi Supergroup, Deccan Trap, Laterite and Alluvium. The Kaladgis unconformably overlie the Archean metasediments and also at places exhibit faulted contacts with the latter. The major part of the area is covered by a thick evergreen vegetation. The interpretation followed by field work and laboratory work revealed the following:

1. The different lithologic units could be delineated on the aerial photographs.
2. Different lineaments marked on the imagery were found to be due either to faults or fracture zones. Some of the older faults appear to have been rejuvenated after the formation of the laterites.
3. Some of the lithologic horizons can be identified on the Landsat imagery by virtue of their spatial signatures.

These studies indicate that even in the area covered with thick vegetation, aerospace imagery in appropriate band and data scale can provide significant geological information.     

The solani-ganga interfluve; an application of remote sensing technique on soil resource mapping for agricultural planning

The area of the Solani-Ganga interfluve, which lies between 29°16′N to 30°15′N latitude and 77°45′E to 78°15′E longitude was undertaken for the present study using LANDSAT imagery of band 5 and 7 and the false colour composite on the scale of 1:250,000 in combination with aerial photographs (1:25,000). Major geomorphic units, e.g., Siwalik Hills. Solani-upper alluvial plain, Solani lower alluvial plain, ‘Tarai’ and Ganga alluvial plain were delineated on LANDSAT and colour composite. Sample areas selected from LANDSAT were studied on aerial photographs in details and soil physiography relationship was developed. The soils on Siwalik hills are classified as Orthents. The soils of the pledmont plain and the recent terraces of Solani river and its tributaries were Psamments, Orthents, Fluvents, Orchrepts and Aquepts. The soils of upper alluvial tract of the Ganga plain is mostly Ustalfs with inclusion of Aqualfs, while the strong hydromorphic Tarai tract consists of partly Aquepts, Ochrepts (cultivated) and partly of Aquolls, Ustolls and Ustalfs (under forest). The present study aims to pin point the nature of soil relief relationship with the help of LANDSAT imagery and aerial photographs and diagnose the intensity of the depletion of soil resources (by prevailing factors like swift run off of biykderfed torrents, fast-flow of ground water, soil creep, mass wasting) through field studies and then treat them with ecological dose of soil conservation. For agronomic development of the region, it is worked out that the present crop-combination and crop-rotation systems should be slightly modified according to its ecosystem to prevent the depletion of soil nutrients.     

Visual comparison of computer aided landsat map and air photo map : A case study from Karimnagar district Andhra Pradesh

The use of aerial photo-interpretation technique in preparing an applied hydromorphological map is discussed. The practical utility of the map for ground water exploration in granitic terrain is presented. An attempt to prepare a similar map using LANDSAT CCT by analysis through a Multispectral Data Analysis System and the relative merits of computer aided map and aerial photo map are discussed. The details available in aerial photo map have been found to be lacking in computer aided map. Visual interpretation of LANDSAT imagery can improve the computer aided classification results.     

Utility of landsat coverage in small scale geomorphological mapping-some examples from India

With the launching of LANDSAT—1 in 1972 followed by LAND-SAT-2 and 3 in 1975 and 1978 respectively, a new tool is now available to earth scientists for a synoptic overview of the earth forms. Existing small scale geological maps, soil maps and forest resource maps are constantly being updated with the help of LANDSAT imagery. The paper highlights the utility of LANDSAT imagery in preparing small scale geomorphological maps by citing examples from such diversified terrains as the Himalaya and rain forest area in the north and NE India and part of east coast. The advantage of conjunctive use of space craft, aircraft and ground data in enhancing the detail and quality of the map is discussed. Further the direct relationship between landform and landuse is brought out in the map. The methodology provides a basis for preparing a small scale geomorphological map for the country, the like of which does not exist so far. In addition, the map provides a basis for attracting attention on exploration of minerals, ground water, morphoconservation, flood protection programming and coastal management. The nominal cost and speed of preparing such map are discussed.     

Visual interpretation of landsat-1 imagery of central and southern districts of Haryana state,India

LANDSAT-MSS data in the form of a false colour composite image at a scale of 1:250,000 has been used to produce terrain unit maps of parts of north west India. The area of study consisted of central and southern districts of Haryana State. It has been possible to obtain a qualitative assessment of land use patterns and surface hydrology by means of visual Interpretation. The boundaries between differeat terrain units and moisture regimes were clearly discernible It is felt that comparative studies of false colour infrared imagery over a period of time can provide valuable Information for those engaged in reclamation schemes. In particular, the data can be used to plan reclamation of salt affected and waterlogged lands in semi-arid zones of states like Haryana.     

COMPUTER PROCESSED LANDSAT LAND COVER MAPS OF HUNGARY

Two studies using LANDSAT imagery are summarized. The urban area study of the city of Budapest uses a statistical classifying method with ground truth to identify eleven land use categories resulting in a 60 to 80% reliability. The rural area study of Komarom County attempts to use LANDSAT to monitor the utilization of farms of agri-ecological research by identifying actual cropland patterns. Translated by the authors and submitted for publication in June, 1984.     

Landsat photo-interpretation for preparation of small scale soil maps through a multistage approach

Landscape units and their sub-divisions were delineated on two LANDSAT photos by visual interpretation on the basis of uniqueness of patterns comprising tone, texture and drainage. Sub-divisions of basalt and granite landscape units could be delineated more precisely with Band 5 photo, while Band 7 photo was found to be superior in respect of the laterite plateau. The soil composition of most of the units was assigned by using data previously collected for the preparation of small scale soil maps adopting a procedure of systematic aerial photo-interpretation with limited selective ground check and authors’ personal knowledge in respect of the remaining units. The resulting soil map has been shown to be superior to existing small scale soil maps for the study area.     

摄影测量和数字图象处理的某些进展

本文从王之卓教授关于\     

Neotectonic and lineament analysis of LANDSAT imagery for oil and mineral exploration—An example from Godavari delta—Eastern Ghats area

Visual Interpretation of LANDSAT imagery of Eastern Ghats-Godavari delta area on scale 1:1,000,000 on spectral bands 5 and 7 was attempted. A neotectonic and geomorphic map was prepared from these images showing among other features major and minor lineaments. The importance of some of these lineaments for sedimentation, oil migration and localisation of ore bodies is discussed.     

Morphometric analysis using remote sensing techniques in the chaka sub-basin, purulia district, West Bengal

Remote sensing techniques using satellite imagery have proved to be an indispensible tool in morphometric analysis and groundwater studies. In the present area, morphometric analysis using temote sensing techniques have been carried out in Chaka river sub-basin of Manbazar Block, Purulia district, West-Bengal, which is one of the most drought affected area in West-Bengal. The parameters worked out include Bifurcation ratio (R_b), Stream length (L_u). Form factor (R_f), Circulatory ratio (R_c), and Drainage density. The morphometric analysis suggests that the area is covered by fractured, resistant, permeable rocks, the drainage network not so affected by tectonic disturbances. Using satellite imageries of LANDSAT and IRS, different hydrogeomorphological units have been delineated. The study shows that moderately weathered pediplains and valley fills are good prospective zones for groundwater exploration.     

Nubra-Gartang Superlineament,Ladakh -some geological observations and their implications

Geological observations along the Leh-Panamic traverse, which includes the northwestern portion of the Nubra-Gartang Superlineament, are being reported. Nubra-Shyok Thrust and the Tirit-Khalsar Fault are two imporant structural features in the area, the latter having a linear trend over regional extent is clearly picked up in the LANDSAT imagery.     

MONITORING ENVIRONMENTAL IMPACTS OF LENINGRAD ON THE SURROUNDING AREA

The author, a remote sensing specialist in Leningrad University's Department of Atmospheric Physics, describes the use of space imagery in a program for monitoring the city's impacts on the surrounding environment. The paper examines applications of LANDSAT and “Meteor” satellite imagery and “Soyuz-22” space photography in the study of industrial smoke plumes, jet contrails, atmospheric haze, albedo, the urban heat island, urban sprawl (including nighttime imagery), fallout of suspended particulates, and wastewater discharges into the Gulf of Finland. Translated from: Grigor'yev, A. A. Antropogennyye vozdeystviya na prirodnuyu sredy po nablyudeniyam iz kosmosa [Human Impacts on the Environment From Observations From Space]. Leningrad: Nauka, 1985, pp. 129-141 [Chapter 7].     

Description of a New Method for Retrieving the Aerosol Optical Thickness from Satellite Remotely Sensed Imagery Using the Maximum Contrast Value and Darkest Pixel Approach

Satellite sensors have provided new datasets for monitoring regional and urban air quality. Satellite sensors provide comprehensive geospatial information on air quality with both qualitative remotely sensed imagery and quantitative data, such as aerosol optical depth which is the basic unknown parameter for any atmospheric correction method in the pre‐processing of satellite imagery. This article presents a new method for retrieving aerosol optical thickness directly from satellite remotely sensed imagery for short wavelength bands in which atmospheric scattering is the dominant contribution to the at‐satellite recorded signal. The method is based on the determination of the aerosol optical thickness through the application of the contrast tool (maximum contrast value), the radiative transfer calculations and the ‘tracking’ of the suitable darkest pixel in the scene. The proposed method that needs no a‐priori information has been applied to LANDSAT‐5 TM, LANDSAT‐7 ETM+, SPOT‐5 and IKONOS data of two different geographical areas: West London and Cyprus. The retrieved aerosol optical thickness values show high correlations with in‐situ visibility data acquired during the satellite overpass. Indeed, for the West London area a logarithmic regression was fitted for relating the determined aerosol optical thickness with the in‐situ visibility values. A high correlation coefficient (r²= 0.82; p= 0.2) was found. Plots obtained from Tanre et al. (1979, 1990) and Forster (1984 ) were reproduced and estimates for these areas were generated with the proposed method so as to compare the results. The author's results show good agreement with Forster's aerosol optical thickness vs. visibility results and a small deviation from Tanre's model estimates.