Study on the Extraction of the Water Bodies from Remote Sensing Image Using ENVI Software – Applied to the River Environmental Protection in Qinzhou
Authors: Qin Wei Rong 
Published: September 2013

In this study, the main water body of remote sensing image was extracted with the maximum likelihood algorithm of ENVI software based on Qinzhou's remote sensing images 2008 and 2011. From the remote sensing images, it was found that the area of the water body was greatly reduced, and also the water body has been polluted differently. In this paper, the urgent environmental protections of Qinzhou's main rivers are analyzed in view of the reduced water body, and also some suggestions on water body conservation are proposed. Overview of Qinzhou Qinzhou is located between V20°52 and 22°41 N, and 107°27 and 109°56 S. The total area of Qinzhou is about 10842.73 square kilometers. It is in the corner of the South China Sea, and is the core base of the north gulf economic region. Thus, it takes an absolute advantage in logistics. The national patriotism education bases for elementary and middle schools in Qinzhou are the former homes of two national heroes (Yongfu LIU, and Zicai FENG). In Qinzhou, there is a coastline of more than 520 kilometers, and many excellently natural harbors such as Qinzhou Port, Longmen Port, Shajing Port, and Siluo Port are available here. Also, there are abundant product advantages. The climate is hot. Many rivers and water reservoirs are available. Soil and plants are flourishing greatly. Since the new century, Qinzhou government as well as the governments of all counties greatly invest Qinzhou, carry out urban and rural clean engineering, urban infrastructure project construction, and agricultural preferential policies, and establish multi-form and multi-dimensional economic and technical cooperation with foreign and domestic companies, in which business is easy to process and the procedures are simple to handle. In 2013, the high-speed rail has brought a new era to Qinzhou. Qinzhou's advantages in climate conditions, rain conditions, and water resources Qinzhou is located in the subtropical zone and features a transitional marine monsoon climate. The overall terrain forms are mountains, hills, terraces plains, and coastal mud flats from northwest to southeast. From east to north, the main mountain is LIUWAN Mountain. From west to north, the main mountain is SHIWAN Mountain. The annual average temperature is 22°C; the absolute maximum temperature was 37.5°C (July 28, 1968), and the absolute lowest temperature was-1.8°C (January 12, 1955). The average annual rainfall is about 1600mm; the average sunshine period is about 1800 hours, and the frost-free period is more than 350 days. The solar radiation amount is 104.6~108.8 kilocalorie/cm2; the annual sunshine duration is 1633.6~1801.4 hours; the annual average temperature is 21.4°C~22°C; the annual total accumulated temperature is 7800°C~ 8200°C. The average frost-free period of previous years was 329~354 days. The water resources advantages of Qinzhou include humid temperature, abundant rain, and annual rainfall of 1600mm~1900mm. Major rivers include Qinjiang, Maolingjiang, Nanliujiang, and Dafengjiang, and the annual runoff is 11.728 billion cubic meters. The gross storage capacity of small, middle, and large reservoirs has reached 805 million cubic meters. Qinzhou's remote sensing image and the river remote sensing images of recent years The water yield of the main rivers in Qinzhou is abundant and falls greatly, so the hydropower resource is rich. The rivers in Qinzhou are small and medium-sized, own a large quantity of flow, and flow into the sea, but do not form drainage.