Geospatial technology is a very important tool for monitoring and analyzing the effects of human activities on the environment. This form of analysis is very important to scientists, geographers and the government. It helps to determine the nature of damages that man can expose to the environment and therefore prompting for the right action to be taken.
Every track of land in different places on the earth’s surface is unique it its own way. No land remains the same forever. At some point in time, it may undergo some transformation that completely changes it appearance. This research looks at the impact of human activities on the vegetation.
Previous studies on the effect of human activities on environment have shown that there is a very strong impact on the environment as a result of the human activities. There are several techniques which have been proposed for analyzing these aspects but according to our main objectives, we are going to analyze the impacts by the use of geospatial technology which is the most efficient of all the technologies currently available. There are several techniques under the geospatial technology which can be used for monitoring and analyzing vegetation cover of a given place. The techniques include:
i. Use of change detection techniques
ii. Use of NDVI techniques
iv. Use of SPOT and FORMOSAT -2 satellite images
All these techniques are used in order to come up with more accurate results which can be used for analyzing and monitoring the vegetation cover of a particular place.
This research is to make use of geo-information particularly image data to evaluate the impact of land use change that was occasioned by the massive human movement into Lagos. It is a research that is intended to create a geospatial model to be used by geographers, ecologists and planners who are interested in analyzing the environmental trend and detecting changes that may be useful for proper allocation of resources. The research also can help to sensitize scientists and other interested parties on the use of geo-information to leverage research efforts in the face of apparent lack of quality data in the sub-Saharan Africa.
According to Hofman et al., (2001) Geospatial Technology also known as geomatics refers to a technology used for visualization, measurement and analysis of features or situations on the earth’s surface. The analysis is done by capturing images from the earth’s surface through the use of satellites over a long period of time. The data is then stored and GIS systems are then used for the analysis.
Campbell (1987) suggests that before embarking on the use of geospatial technology to carry out some research, it is important that one gets the ground information first. This will help in the analysis and production of accurate data. He observes that, research carried out without involving the inhabitants is not likely to be as accurate as the one conducted with the ground data.
Adams and Gentle (1978) used digitized aerial photos in monitoring the changes in the waterfowl habitat over a 10 year period in the Manitoba parklands. Nichol (1975) on the other hand observed that the variations in the photographic density on the true color transparencies correlated well with the intra-habitat parameters.
Futurist John Naisbitt established a very powerful approach when he said that “whenever a new technology is introduced into the society, there must be a counterbalancing human response – that is high- or the technology is lost. The more high tech, the more high touch (Naisbitt, 1989). He observed that the new technology is not being adopted by geographers and government agencies due its complexity and high costs involved. However, he suggested that its adoption can save the government billions of dollars as it can facilitate proper planning and efficient use of the natural resources.
Vitousek and Walker (1989) observed that the invasions of invasive species can have major impacts to an environment. The invasions are the major threats to environmental biodiversity. Some of the parts of an environment that are likely to be affected most include the native plants and animals which are confronted with extinction in case they are not properly protected. This was a confirmation to Sabins earlier research which established that a successful control of invasive species requires a clear picture of the spatial extent of infestations. He stated that using the geospatial system helps in understanding the environment better and accurately. (Sabins, 1987). Sabins concluded that the geographic information serves as a means of integrating and manipulating the surface observations. The satellite based environmental indicators serve as an effective tool for planning, decision making and for research purposes. The use of the GPS technology facilitates this form of integrating information whereby it gives the exact locations in terms of coordinates of land observations.
Campbell (1987) established that the land observations that are gathered for study no longer require markers and can be easily evaluated even for remote locations (Campbell, 1987) The evaluation of individual and composite GIS data layers will be able to permit the assessment of the risk of desertification in a timely manner and fashion. The use of geospatial technology over a given duration of time will help in monitoring and giving accurate results at the end of the research process.
Jian Yeou et al., (2007) proposed a mechanism that uses multitemporal and multisensory satellite images to monitor the dynamics of a watershed for the purpose of disaster monitoring and assessment. They used SPOT and FORMOSAT -2 satellite images which had a high acquisition frequency to monitor the dynamics of the water shed. They took images at the beginning of the study and then some more images at different times during the study. Images taken at the beginning of the study were different from those taken at the end of the study. This helped in carrying out the analysis and making conclusions on how the use of satellites can help in monitoring and carrying out the research.
They further implemented a system that could aid in change detection analysis. The system combined the change vector analysis (CVA) and the Normalized Difference Vegetation Index (NDVI) to detect the land cover changes. This system can be used in monitoring the land vegetation cover of a particular place. The use of NDVI provides for the Standard Index used for comparing the vegetation chlorophyll using the satellite images. In our research we are going to adopt the two methods (NDVI and CVA) in order to obtain accurate results in the study. This is because a change in land cover form vegetation to bare soil results into a more significant reduction in the NDVI than in the CVA magnitude. (Jian Yeou et al., 2007)
They also proposed a mechanism that could be applied in the monitoring of vegetation recovery. Their comparisons showed that once the environment has been degraded by either the human activities or natural calamities, man-made reconstruction is more effective. This can only be properly done if the budget is sufficient and therefore governments are advised to take up the task of ensuring that there is a proper allocation of funds for such forms of recovery in order to restore the environment to its original state. (Jian Yeou et al., 2007)
Lucas (2001) in his research, developed a system to monitor and study the ecological health of aquatic systems and asses the impacts caused by human activities to their habitat. His main focus was to characterize stress response relationships using advanced geospatial approaches. He discussed the coupling of climatic-land systems. He also applied the integration of remotely sensed biophysical measurements with management information at multiple scales to examine the nature and magnitude of the interactions of land use/land cover and climate changes. Much of his time during the study was devoted to be focusing on the investigation of land surface dynamics and quantifying the impacts of the human activities on the environment. He used geospatial technology to monitor the impacts of human activities on vegetation cover.
The Earth observation satellites he used were able to demonstrate their utility in providing data for a wide range of geographic applications. Some of the applications include; forest fires, spread of desertification, flood monitoring, estimation of crop and forestry changes and monitoring of the land use and changes. The remotely sensed data he used provided historical information from which the geographical trend of the place of study was compiled to indicate the most affected region. This approach has been applauded by many scientists and geographers due to its accuracy and its ability to offer information accountability.
Kathleen V. Schreiber (****) observed that the vast spatial extent of drylands and the inability of the inhabitants to effectively measure land degradation has limited the ability of understanding in order to address and prevent desertification. She proposes the use of the Normalised Difference Vegetation Index for calculating vegetation Density and stress. She proposes an expression for the NDVI as 0 or Negative values are an indication of no green leaves.
Her research demonstrated the capability of using NDVI techniques for capturing data covering large area of land over a long time frame. This technique makes it possible for the analysis of large and complex data generated from the digital numbers in pixels associated with the raster image data. This is used to produce useful information on the characteristics of the landscape due to the impacts of human activities.
Foster (1991) observed that human activities are the significant drivers that determine the nature of the environment. The mass movement of people and the rapid land use change can lead to several environmental disasters like flooding and heat wave. The study provides a model that can be used for monitoring environment occurrences and helping to make decisions that can prevent further destruction of the environment.
Satapathya & Katpatalb (2007) mapped temporal changes of vegetation using DNDVI technique. They also made the use of vegetation index differencing technique to analyze the changes in vegetation and non-vegetation. This technique is based on the principle of spectral difference based on strong vegetation absorbance in the field. (Satapathya & Katpatalb, 2007)
Using their method, two reading were taken on different dates and then used to calculate the DNDVI. The following equation for change detection was proposed: Whereby t1 was the first date and was the day the second reading were taken.
They observed that the low cost of the imagery is an advantage for the managers of the natural resources especially in the developing countries. The urban planners can use the information for proper and efficient planning. According to them, this information can also be used for checking and controlling the human activities and their impacts which allow users to monitor new developments and also design methods which can be used to asses whether environment are degrading as a result of resource utilization.
They state that the use of remote sensing and GIS is an essential component of the Environmental Impact Assessment (EIA) process. This is because the environmental resources are directly affected by the changes which are propagated by the human activities. They propose the use of both the RS and GIS as it is a very important tool for decision making about policies, plans and implementation of projects. This is because the results got from these techniques are easy to analyze and are usually very accurate. From the previous study, it can be inferred that Environmental Impact Assessment using the geospatial tools can be a successful process in considering certain components like baseline information and the formulation of management plans for subsequent developments. (Satapathya & Katpatalb, 2007)
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