SCIENTIA GEOGRAPHICA SINICA ›› 2014, Vol. 34 ›› Issue (1): 122-128.doi: 10.13249/j.cnki.sgs.2014.01.122

• Orginal Article • Previous Articles    

Demarcation of the Horqin Sandy Land Boundary Based on Remote Sensing and GIS Technique

Yan YAN1,2,3(), Jiao-jun ZHU1,2, Qiao-ling YAN1,2, Xiao ZHENG1,2,3, Li-ning SONG1,2   

  1. 1.State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110164, China
    2.Liaoning Key Laboratory for Management of No-commercial Forests, Shenyang, Liaoning 110016, China
    3.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-01-10 Revised:2013-02-03 Online:2014-01-10 Published:2014-01-10

Abstract:

Horqin Sandy Land is one of the key regions for desertification prevention and control in China. However, there is lack of exact boundary of Horqin Sandy Land at present. Subsequently, the control and recovery process of environment in this region is affected. Based on both the existing literatures and the formation history and earlier distribution of the Horqin Sandy Land, the core region of the area was first determined in the present study. Then, 26 intersections for the boundary of the core region from 16 directions were taken as the samples using the ecology sampling method. Remote sensing and GIS methods such as linear spectral mixing model and tasseled cap transformation were adopted to process the Landsat-5 TM images in the study area. Three components after tasseled cap transformation (i.e. brightness, greenness and wettness) were used to identify the sample points in the southern nine directions. Based on multiple replication tests, optimal thresholds were selected by obtaining the demarcation characteristics of each intersection sample and the exact boundary of Horqin Sandy Land was delineated accordingly. The linear spectral mixing model was applied in the northern directions because the sandy land and saline-alkali soil were distributed crossly. Combined with the optimal thresholds, the northern part boundary was delineated accordingly. However, this method was inapplicable to two directions and the thematic map of land use types was used to explore the demarcations. Subsequently, field investigation, high resolution images provided by Google Earth and the permanent geomorphology features were combined to confirm each direction of the final boundary of Horqin Sandy Land. According to the verification, the boundary was adjusted slightly. The results showed that the area of Horqin Sandy Land was 52 300 ± 360 km2 with the verification accuracy greater than 94%. The errors were caused mainly by the set of threshold values, precision of spectral unmixing results and the resolution of images. The achievements in the present provide the reference to eco-regionalization and environment monitor and ecological restoration in the definite confines in Horqin Sandy Land.

Key words: ecology sampling, ecological regions, tasseled cap transformation, spectral mixing analysis, Horqin Sandy Land

CLC Number: 

  • Q149/TP753