Studying MODIS Satellite Data Capability to Prepare Vegetation Canopy Map in Qazvin Plain Rangelands

Using satellite imagery is a reasonable option to overcome the field visits problems and limitations to evaluate the vegetation cover over the years. The present research has conducted to specify the percentage of vegetation cover of rangelands using Geographic Information System (GIS) and vegetation indices. The study area is located in Qazvin plain rangelands, Iran. In this study, the MODIS satellite images was used to extract the vegetation canopy percentage map in June 2017. To make a correlation between vegetation canopy percentage and satellite data, 160 plots (10*10 m2) were marked on the study area with an area of five thousand square kilometers so that each 10 plots was located on the perimeter of a hypothetical circle with a radius of 150 meters having 100 meters interval. Vegetation indices were extracted from the satellite images. The correlation between vegetation indices and field data were calculated by analyzing simple linear regression. Then, a vegetation cover model obtained for each of the vegetation canopy percentage. The study results showed that the correlation coefficient of the NDVI and EVI indices were 0.63% and 58% respectively and the NDVI index was selected to prepare vegetation cover map because it had the highest correlation coefficient. Using the NDVI index model, the vegetation canopy for five percentage classes namely 10%>, 10 -20%, 20 -30%, 30 -50% and more than 50% were prepared. The study results showed that 10 to 20% vegetation canopy class is prevailed. The study results also showed that MODIS and NDVI indices are suitable tools to create vegetation canopy map in the rangelands dominated by shrubs and grasses.