estimation of vegetation and land use changes using remote sensing techniques and geographical information system (case study: roodab plain, sabzevar city)

land use may be regarded as one of the most important factors affecting theenvironment with respect to human activities. so far, destroying the rangelands andchanging them into the waste lands and poor rangelands has been proposed as the mostsignificant variations of land use done by human beings. this paper has been conducted toevaluate the variations of vegetation percentage and land uses in barabad-darook villagewith the area of 1522.99 km2 in sabzevar city during 1987-2007. thus, using satellitebasedimages of tm and etm+, the most appropriate band composition has been selectedand a mapping of vegetation cover and land use was provided through maximumlikelihood algorithms to correct the errors of geometer and radiometer highlights. at last,the accuracy of extracted maps was to be determined by the means of overall accuracy testand kappa coefficient in order to achieve the validation of research process. resultsindicate that waste lands have been increased from 84.75 to 89.49 and third-ratedrangelands have been reduced from 6.85 to 4.14 percent. on the other hand, first-ratedrangelands were reduced from 0.03 to 0.01 percent which covers 5170791.45 m2 of totalarea in the district. also, the results show that irrigated agricultural lands are to bedecreased from 6.53 to 0.07 percent. in total, due to improper exploitations of regionalwater resources and vegetation cover, land uses have been changed into fallow and wastelands leading to the decrease in the percentage cover of high quality rangelands. researchfindings demonstrate that considering the accepted accuracy, new remote sensingtechnology can be applied to exactly estimate the area changes of land use and vegetation.