Spatio-temporal variations of vegetation cover in northern Shaanxi Province under the background of ecological restoration. Dynamically Monitoring Vegetation Cover by Remote Sensing in the Typical Salinization Region of Xinjiang: A Case Study in Delta Oasis of Weigan and Kuqa Rivers Dynamic monitoring of fractional vegetation cover along Minjiang River from Wenchuan County to Dujiangyan City using multi-temporal landsat 5 and 8 images A Study on Estimation of Vegetation Fraction by Using QuickBird Imagery Monitoring Vegetation Coverage Degree of Forestland Converted from Cropland by Applying High Resolution Satellite Image