Global Scan Technologies
Email: [email protected]
The socio-economic development of any country is based on land resources and water resources. Due to increase in population, these resources are over stretched often leading to resource depletion. There is need to prudently manage these delicate resources. Remote Sensing and GIS techniques can be applied effective measure to generate data and information for sustainable development. After more than 25 years of satellite-based land remote sensing experimentation and development, these technologies reached almost all sectors of Earth science application. The use of remote sensing data and derivative information has ever promise of entering into mainstream of governing at local and regional level.
Global Scan Technologies, Dubai implements the latest advent in spatial mapping technologies for natural resource survey and management and have carried out various project for UAE Government Organisation. The application includes :
- Landuse / Landcover study- Visual and digital interpretation of satellite imageries are implemented to prepare pre-field map based on spectral/tone/texture homogeneity. Pre-field interpreted map and digitally enhanced satellite data is used on the ground to identify different land use and land cover classes and to generate geodatabase for the land use and land cover.
- Vegetation Mapping- The classification system is open ended and is based on globally followed principles of vegetation classification using Climate/ Physiognomy / floristics. Based on the spatial extent, separability using remote sensing and ground information on vegetation distribution a geodatabase has been generated for Vegetation theme.
- Soil Mapping – The satellite data is interpreted based on photo-elements like tone, texture, size, shape, pattern, aspect, association etc. The first step in image-interpretation is the delineation of landscape units. The discrimination of landscape units and soil mapping units is based on lithology, relief, drainage pattern, natural vegetation, and sometimes land use along with the associated image elements . Field Survey is executed proceeding the preliminary interpretation of satellite imagery. The soil mapping units is evaluated for different land capability classes following USDA land capability classification based on soil, topography etc., limitations
- Geology and Hydrogeology mapping- The first step in generation of Geology and Hydrogeology Map is the Preliminary interpretation of satellite imageries for demarcation of Lithological boundaries, lineament ,other structural feature interpretation and characterization of various geomorphic units.
Extensive field survey has been taken to verify the pre-field interpretation data and finally the lithology, geomorphology and structural maps are integrated to finalize the map and to generate Geodatabase for Geology and Hydrogeology Themes.
Global Scan Technologies, Dubai is implementing the latest and cost effective solution for Thematic Mapping in United Arab Emirates and Worldwide. The thematic mapping services includes Geology, Geomorphology, Hydrogeology, Vegetation, Soil and Land use Land cover studies. The following article enumerates such a study carried out for the part of Middle East Region.
A brief methodology for execution of this project is explained as follows:
The satellite data of the study area are procured from IRS-P6, LISS-III & LISS-IV and has been used for Geology, Geomorphological, Soil, Vegetation and Land use Land cover studies. Published soil maps, topographic maps, climatic data etc. are also collected and used as collateral data.
The IRS P6 satellite data were geo-referenced and suitable Image enhancements are applied to facilitate the delineation and interpretation of different thematic information.
Visual and digital interpretation methods were used to prepare pre-field interpreted map. The satellite data is interpreted based on photo elements like tone, texture, size, shape, pattern, aspect, association etc. These pre-field interpreted maps and digitally enhanced satellite data are used on the ground to identify different elements of various themes.
Field Verification and Data Collection
Suitable field sampling designs in terms of line transects/ quadrants are used to assess the interpreted elements and relate with satellite data. The field data collections are aided by GPS in order to locate the ground verification points on the image and for further incorporation of details. For the all the sample collection and field points visited attribute information on vegetation, geomorphologic, soil and topographic parameters are also collected.
The detailed soil-site study was undertaken in each soil-mapping unit by general traversing and by collecting surface soil, minipit and soil profile observations at intervals depending on soil variability
The sample points were decided based on the geological / Geomorphological / soil heterogeneity mapped from the satellite data.
Finalization of Maps
Based on the pre-field interpretation, ground truth verification and available secondary information final maps were prepared in 1: 25000 scales. Towards this both visual and digital approaches are conjunctively used.
Project Flow Chart
Land use Land cover
The land use and land cover map is prepared using RESOURCESAT LISS IV satellite data. The classification scheme was designed keeping in view of the management practices addressing each land use/ land cover parcel, amenability of these parcels for identification/mapping in LISS IV dataset. Under the Level-I classification, Built up, Cultivated areas, Woody vegetation, Grasslands, Wastelands, Wetlands and Water bodies were segregated. In addition subclasses of Level-I LULC classes observed based on spectral satellite data and were evaluated on the ground, to characterize them as information classes. All the LULC classes were visually interpreted based on tone/texture, contextual and ground information. The major information class in the study area is ‘built up areas’ was consisting of urban and rural fringe landscapes and the urban built up areas were dominated by residential, mixed residential and industrial areas. The rural landscape essentially consisted of settlements, camel camps and cultivated areas. Statistical data of community wise built up area was generated and analyzed.
The vegetation cover map is generated using IRS Resourcesat LISS III & IV. The vegetation in the study area is regulated by desert climate, seasonality, physiographic, geomorphologic and soil regimes. The vegetation is broadly demarcated into natural and managed vegetation. The natural vegetation mainly consisted of formations of Mangroves, Prosopis, Leptadenia. The managed vegetation mainly consisting of avenue plantations, grasslands, lawns, golf courses and palm /mixed plantations. Phyto-sociological analysis was carried out after collecting sufficient number of sample data from the natural vegetated areas. The vegetation mainly mangroves, Prosopis, Laptadenia are further stratified into dense and open canopy density classes. Further different categories of vegetation under each of the community has been extracted and analyzed to understand the percentage of vegetation present to that of vacant land. Such information on spatial distribution in qualitative and quantitative terms would be useful in further exploring and analyzing the aspects of biodiversity and ecological conservation
The soil is mapped using remote sensing satellite data IRS- P6 LISS IV. The soils of the study area were classified upto series level and their association’s level as per the Keys to Soil Taxonomy (Soil survey staff, 2003). .
Essentially soil survey is a study and mapping of soils in the field. It is the systematic examination, description, classification and mapping of soils of an area and it comprises of a group of interlinked operations involving
- Preliminary visual interpretation of satellite data
- Fieldwork to study important characteristics of soils and associated land characteristics such as landform, natural vegetation, slope etc.
- Laboratory analysis to support and supplement the field observations.
- Correlation and classification of soils into defined taxonomic units.
- Mapping of soils – that is establishing and drawing soil boundaries of different kinds of soils on standard geographical base map.
- Generation of Geo-database for Soil
The geo-referenced satellite digital data was used to carry out ‘on screen’ vectorization of geological parameters. Basically three vector layers were generated in. The first vector consists of geological structure attributes with length based classification second vector consists of geomorphic attributes and the third vector consists of broad litho logical map. In the case of image processing, spatial and spectral domain enhancement was carried out using ENVI software. The following steps were involved:-
- Satellite data has been be geo-referenced with the available map sheets.
- LISS-3 / Liss-4 and AWIFS data were be acquired for the entire study area
- LISS-3 was used for regional assessments and LISS-4 data was used for detail assessments.
- These data sets were co registered with other collateral data sets by taking common Ground Control points (GCP).
- The satellite data was enhanced both in spectral and spatial domain.
- A optimised image was generated for visual / Onscreen interpretation.
- The existing geological map was not available for the area and hence using geomorphic analysis, field and published literature a broad level lithological map was prepared.
- The geological structure map was prepared with mainly on type of lineament with emphasis on length, Faults and thrusts
- The geomorphological map was prepared with emphasize on genetic classification of landforms. The major group are coastal landforms, aeolian landforms, and structural landforms.
- A pre-field map was prepared using satellite data
- Ground validation was carried out with emphasis on selective ground checks
- The ground observation was incorporated at appropriate places to finalize post field map
- All the three themes have been integrated in GIS environment to generate hydro-geomorphology map.
The generated theme can be implemented for further planning of the urban and rural area .The action plan report can be created using the Geodata database and total decision support system can be developed to depict location and type of action / control measures recommended for sustainable development plan of Natural Resource. Zonal and Community wise Soil resource development plan, Water resource development plan, Vegetation resource development plan, Land use and Land cover plan can be incorporated using statistics of the personal Geodatase of the respective Theme.