Abstract

Over the last decade, the normalized difference vegetation index (NDVI) differencing method and classification method are widely used as a change detection method and provides detailed information for detecting and monitoring changes in land use-land cover (LULC). So in the presented study to raise awareness for the LULC change in Ardakan, Iran, two Landsat ETM+ images of the years 1990 and 2006 have been prepared and used to derive NDVI images and perform image classification. At first stage, differences between two correspondent NDVI images of the area was calculated and threshold to demonstrate the areas with 10% increase or decrease in NDVI values. From the results, the 18.83% of the region’s NDVI values have decreased by about more than 10% from 1990 to 2006, while only 1.38% of it has increased at the same time period. At second stage, supervised classification was performed and outputs of the two time periods were compared to derive information on changes that occurred over a period of time. During the study period, urban areas were increased from 10.68% of the total land in 1990 to 17.16% in 2006 whereas, the agricultural lands were decreased from 30.15 to 21.76% in the same period.

Key words: Change detection, normalized difference vegetation index (NDVI), density slice, band math, image classification.