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A new method for calibration of land-vegetation degradation modeling
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Zahra Jahantab *   , Ali Asghar Ale Sheikh , Ali Darvishi Boloorani , Keivan Bagheri |
| Islamic Azad University |
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Abstract: (3483 Views) |
| One of the main challenges of human is the dramatic decrease in resources due to human’s excessive consumption of land that has led to a phenomenon called land degradation. Various models have thus far been introduced for assessment of this phenomenon. The parameters and their weights differ from one model to another as per experts’ opinion. The present study introduces a new method to identify and calibrate the parameters, as per the conditions of the region under study, affecting this phenomenon. The proposed method is considered as a data-based model such that parameter weights are computed intelligently and as per the climate and geographical conditions of the region. The genetic algorithm and Weighted Overlay Index were used to determine the significance level and ranking of the criteria. For the purpose of assessment, the data pertaining to Neinava region, located in Iraq, including Landsat satellite images of 1985, 2001, and 2014 as well as criteria such as distance from rivers, distance from lakes, distance from agricultural areas, distance from roads, distance from residential areas, height, slope, distance from Qanats, distance from wells, erosion, type of climate, and NDVI index were used. The results obtained from modeling and calibration as per the proposed model were compared with those of the regular method (application of equal weights). Application of genetic algorithm and calibration of weights yielded a standard deviation of 0.03 for prediction of vegetation degradation which is considerably lower than that yielded by the regular method (0.137). The criteria were also prioritized at this stage as per their significance. To ensure the model accuracy, data of 2001 and 2014 were used to assess the obtained results. The assessment result yielded a standard deviation of 0.053 and accuracy of 0.857. After the accuracy of the model was ensured, the vegetation degradation was predicted for 2027. The average rate of decreased NDVI values indicates the critical status of land degradation in the region under study. |
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| Keywords: Land and vegetation degradation, calibration, Weighted Overlay Index Model, GIS, Genetic Algorithm |
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Full-Text [PDF 2326 kb]
(1757 Downloads)
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Type of Study: Research |
Subject:
GIS
Received: 2016/08/23 | Accepted: 2017/04/29 | Published: 2018/09/22
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