Posts

Buffer Analysis Using QGIS

Image
IntroductionGIS provide many tools for understanding and analysis of spatial data base. GIS has capabilities to analyze feature itself as well as its surrounding area and impact of surrounding area on that earth feature. GIS functions play significant role in the data creation, edit, manipulation and analysis. There are ‘n’ number of function available in GIS based on mathematical, statistical and spatial approach such proximity analysis, buffer analysis, spatial analysis etc. 
Buffer analysis is used to delineate areas in proximity to geographic spatial feature. In this a buffer is generated around that existing geographic feature by using distance parameters and this buffer area is used to identify and analyze spatial features comes into that buffer area or outside that buffer area. 
In the buffer analysis a buffer area of specified distance from geographic feature is created then this buffer area can be used to specify the spatial features fall in that buffer area and features are be…

Interpolation Process of Spatial Data in GIS Environment using QGIS

Image
Introduction Continuous spatial data is very important in many applications for spatial analysis. So for such analysis, acquiring continuous spatial data is very difficult, costly and usually takes very long time for study area. In case, if one needs to collect/create continuous data then field sampling and observations is very common practice, such as water sampling for quality analysis. But during this field sampling process, it is nearly impossible to collect data from each and every spot of field, usually samples collected at certain distance. So this distance gap/interval between two samples/more samples is not possible to cover as well as very tedious and time consuming. In this case, some representative samples such as water samples from all well locations or pollution parameters from air monitoring stations will be collected and interpolation method is deployed to create continuous layer. Accuracy of interpolated spatial data depends upon the quantity and spatial distribution …

Digital Image Processing-Introduction to Image Classification

Image
IntroductionClassification is a simple process to categorize or sorting of data based on defined categories or criteria. Such as students in class can be categorized based on marks obtained in maths- number of student below 40%, number of students between 40-60%, number of students between 60-80% and number of students having more than 80%. So based on this criteria student can be categorized or sort in to four different class/category. This is a very simple and basic approach of classification to understand behavior of data in quantitative and qualitative both ways. 
This classification approach is used to classify satellite image. in the satellite image classification process, images are classified based on categorization and classification of pixel values present in satellite image. The pixel value present in each pixel is also called DN values (Digital Number), which is representation of reflectance values received by sensor of earth surface feature. It is already explained in prev…

Application GIS and Remote Sensing in Wetland Mapping-Case Study

Image
Remote Sensing and GIS in Wetland MappingWetland mapping provides useful and important information for assessment of water resources and also for conservation and management of wetland. Remote Sensing and GIS techniques have huge potential for mapping, monitoring and assessment of wetland resources. There are better options to the users for wetland mapping, due to advancement in remote sensing and GIS technologies. As variety of remote sensing images are available with better and finder spatial and temporal resolution. As well as stereo satellite images are also available for effective and accurate mapping and estimation. These high resolution and stereo images can be used to wetland database and integrated with GIS for further analysis such as change simulation, scenario based predictions for better planning and monitoring.  Wetland Mapping Process through Remotely Sensed Images In the study the wetlands of Rajasthan falling in different ecological regions ranging from humid to hot ar…

Remote Sensing Application in Wetland Mapping

Image
Inland Wetland Environment Wetlands refer to lowlands covered with shallow and sometimes temporary or intermittent waters. Wetlands include marshes, swamps, bogs, wet meadows, potholes, shallow lakes and ponds. However deep lakes, reservoir and permanent waters of streams are not considered as Wetlands. Hence we can say wetlands are transitional lands between terrestrial and aquatic systems where the water table is usually at or near the surface.  Importance of wetlands Wetlands posses a great ecological significance in terms of, net primary production, micro-climatic control, ground water recharge and habitat to large number of flora and fauna. It also plays a vital role in nutrient recycling and storage as well as biodiversity conservation. Wetlands help to retain water during dry periods, thus keeping the water table high and relatively stable. Threats to wetlands Rapidly expanding human population, large scale changes in land use, different development projects and improper use of w…

GIS Application to Assess Relationship of Thermal Stress on Coral Bleaching

Image
IntroductionGIS is an extraordinary tool that can be used for variety of applications. It can used to make harmonic, statistics and analytic relation between two different types of data by incorporation of spatial touch in the process. GIS gives a platform to create, edit, analyze, predict and scenario based analysis of database for monitoring, planning and management. For example impact of population growth on land use change, anthropogenic pressure on surrounding water bodies etc. can be assessed using GIS and its functions.  Coral health is affected by various factors induced by human and natural. Many factors such as runoff, sediment discharge, water quality and sea surface temperature plays significant role in growth of coral. Thermal stresses can be represented by change in sea surface temperature and these stresses may affect the coral health. Coral can be categorized based on health as healthy coral, partial bleached coral, fully bleached coral and dead coral. Increase in these…

Remote Sensing Application to Assess Thermal Stress in Coastal Ecosystem

Image
IntroductionThermal variations always affect the natural phenomenon whether it is land or sea. These variations bring changes on the earth features such as reduction in vegetation with increase in temperature. At the same time these thermal variations affect the coastal ecosystem and its habitats. Coral reef, which is also the part of coastal ecosystem, will also change with the variation in temperature.  The ideal temperature for coral growth is 18oC, however many coral species can survive in water temperatures between 23oC-29oC. Bleaching can be induced by short-term exposure (i.e., 1-2 days) to temperature elevations of 3oC to 4oC above normal summer ambient values or by long-term exposure (i.e., several weeks) at elevations of 1oC to 2oC.  The rise in sea surface temperature can cause stress on Coral reef ecosystem, which may result in coral bleaching followed by coral mortality.  The role of remote sensing and GIS become very significant in such type of mapping and analysis. As remo…

Remote Sensing Application for Coastal Studies

Image
In this article remote sensing application is used for mapping of physical feature of coastal ecosystem. Coral reefs are mapped using satellite images. Coral reefs are described as live coral, dead coral and coral in bleaching condition.  Need of Coral Mapping Coral reefs are the foundation and primary structure of highly productive and diverse marine ecosystem. This is the reason, Coral reefs are called the “rainforests of the sea,” Corals grow in shallow water close to the shore and thrive within a limited range of temperature, salinity and turbidity. These ecologically and economically important marine habitats have been significantly degraded and destroyed by human and natural disturbance such as global warming or rise in sea surface temperature. When the environmental conditions that the coral requires are altered, the stress placed on the coral often causes bleaching. Decline in the density of zooxanthellae leads to coral bleaching. Large-scale bleaching is predominantly triggere…

GIS APPLICATION FOR LAND MANAGEMENT- Landscape Development Index Integrated in GIS

Image
IntroductionGIS can be used as planning tool for urban development, transportation planning, land use management etc. GIS provide versatile mathematical and statistical integrated tool for analyzing spatially for proper management. These tools can be used in combination for certain type of analysis and plan accordingly. There are many areas such as assessment of revenue generation for any city/village in GIS can be used as important tool for better management.  Land management is one of the key concern area for local authority to effectively use and manage. As single policy and planning may change land cost and its utilization. There are many factors which affect the land management and most of them are location based factors. So GIS is significant tool to manage and restrict use planning for land management. In GIS many basic methods such as area ratio method, euclidean distance etc. can be integrated to assess the impact of surrounding development and environment on land. Landscape De…