Researches on remote sensing monitoring of newly-construction land based on double-difference model in Chongqing city, China

In this paper, applying Normalized difference vegetation index (NDVI) to build double-difference model with TM images, identified the regions of newly-construction land expansion in Chongqing city. After be standardized, the NDVI was applied to build double-difference model. Applying TM images in the year of 1988, 2000 and 2007, the process of newly-construction land expansion was revealed base on double-difference model. The results indicate that the change of newly-construction land expansion was obvious in Chongqing city from 1988 to 2007.The total area of newly-construction land expansion quantity in the years from 1988 to 2000 was small than the years from 2000 to 2007 in Chongqing city. The region with largest expansion area was transformed from Yubei district to Dadukou district. The total speed of newly-construction land expansion quantity in the years from 1988 to 2000 was slow than the years from 2000 to 2007 in Chongqing city. The region with fast speed of expansion was always Yuzhong district. The regions of newly-construction land located around center parts mainly in Chongqing city from 1998 to 2000, and located on center parts from 2000 to 2007. This research can provide a new method to government to monitor urban expansion.