地球信息科学学报 ›› 2020, Vol. 22 ›› Issue (12): 2436-2444.doi: 10.12082/dqxxkx.2020.190744

• 遥感科学与应用技术 • 上一篇    下一篇

基于无人机航摄影像的喀斯特地区裸岩信息提取及景观格局分析

张志慧1(), 刘雯1,2,*(), 李笑含1, 朱靖轩1, 张洪涛1, 杨东3, 徐超昊3, 徐宪立3   

  1. 1.湖南师范大学资源与环境科学学院,长沙 410081
    2.湖南师范大学地理空间大数据挖掘与应用湖南省重点实验室,长沙 410081
    3.中科院亚热带农业生态研究所,长沙 410125
  • 收稿日期:2019-12-02 修回日期:2020-03-02 出版日期:2020-12-25 发布日期:2021-02-25
  • 通讯作者: 刘雯 E-mail:zhihui616713@163.com;liuwenww@gmail.com
  • 作者简介:张志慧(1994— ),女,山东枣庄人,硕士生,研究方向为遥感信息提取和景观格局研究。E-mail: zhihui616713@163.com
  • 基金资助:
    国家重点研发计划项目(2016YFC0502400);国家自然科学基金项目(41501478)

The Spatial Distribution Pattern of Rock in Rocky Desertification Area based on Unmanned Aerial Vehicle Imagery and Object-oriented Classification Method

ZHANG Zhihui1(), LIU Wen1,2,*(), LI Xiaohan1, ZHU Jingxuan1, ZHANG Hongtao1, YANG Dong3, XU Chaohao3, XU Xianli3   

  1. 1. College of Resources and Environment Science, Hunan Normal University, Changsha 410081, China
    2. Key Laboratory of Geospatial Big Data Mining and Application, Changsha 410081, China
    3. Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
  • Received:2019-12-02 Revised:2020-03-02 Online:2020-12-25 Published:2021-02-25
  • Contact: LIU Wen E-mail:zhihui616713@163.com;liuwenww@gmail.com
  • Supported by:
    National Key R&D Program of China(2016YFC0502400);National Key Research and Development Program(41501478)

摘要:

喀斯特地区不同石漠化等级的结构和格局是实现区域石漠化治理的重要基础信息,受技术手段的限制,目前这方面的研究进展仍非常缓慢。随着无人机技术的快速发展,高精度的地表信息获取越来越方便、且成本较低。本研究利用无人机影像,对比了基于像元的非监督和监督分类方法以及面向对象的分类方法在裸岩信息提取中的表现,发现面向对象分类结果具有更高精度。基于获得的裸岩分布信息的研究结果表明:① 岩石平均斑块面积与裸岩率呈负相关的关系,岩石斑块个数与裸岩率呈正相关关系;② 通过对比不同裸岩率(11%、20%、29%和48%)基质的景观斑块指数、景观形状指数和景观破碎度指数对不同裸岩率的景观分布的影响,从而表明了在不同的石漠化地区随着裸岩率的增加,岩石形状指数与岩石破碎度指数均逐渐增加,进而表明石漠化程度越严重;③ 裸岩率不同的地区表现不同的分布形态和斑块特征,裸岩率越高,岩石越破碎,斑块分布较为分散。小尺度斑块景观格局与区域的生态过程有着重要关系,开展小尺度景观格局的研究会深化区域尺度石漠化发展过程的理解。石漠化地区的小尺度斑块景观格局变化影响区域的生态过程,对以后的石漠化过程以及未来石漠化演变的发展有重要的启示作用。

关键词: 石漠化, 景观格局, 斑块大小, 分布格局, 面向对象分类, 无人机, 裸岩率, 分类, 喀斯特地区

Abstract:

The change of landscape pattern has an important influence on the material and energy flows of ecological environment. Quantifying the landscape pattern of rocky desertification in a karst area is very important for understanding the development of rocky desertification. Rocky desertification is a dynamic land degradation process, which is a comprehensive reflection of vegetation, bedrock, soil cover, and other surface factors. Particularly, exposed bedrock acts as a key indicator of karst rocky desertification. In this study, spatial distribution of rock patches with varied bare-rock ratio (11%, 20%, 29%, and 48%) is characterized using an Unmanned Aerial Vehicle (UAV) image in a rocky desertification area in Guizhou Province. The classification methods for this small-scale UAV image include unsupervised classification, supervised classification, and object-oriented classification. The existing supervised and unsupervised classification methods based on pixels cannot meet the requirements of accurate extraction of rocky desertification information in karst rocky desertification area with complex geological environment. So an optimal classification method is selected to classify the UAV image of rocky desertification in our study. Our results show that the object-oriented classification method has higher accuracy than the others, which reduces the “salt-and-pepper phenomenon” caused by complicated topography. Based on object-oriented classification, the UAV image is interpreted first, and the distribution characteristics of rock patches with different bare-rock rates (i.e., 11%, 20%, 29% and 48%) are quantified by combining various indices in landscape ecology including landscape patch index, landscape shape index, and landscape fragmentation index. Generally, the average patch area of rock is negatively correlated with bare-rock rate. With the increase of bare-rock rate in different rocky desertification areas, the number of rock patches gradually increase with increasing rock shape index and rock fragmentation index, which indicates the increase of rocky desertification. The exposed bare rocks in this karst area show different distribution patterns and characteristics under different rocky desertification rates. The higher the rate of bare rock is, the higher the degree of rock fragmentation is, with a relatively scattering distribution of rock patches. Analyzing the rock distribution for a rocky desertification area can provide support for the evaluation and management of rocky desertification areas. Since the changes of small-scale, small-patch landscape pattern in rocky desertification areas can affect the ecological processes, our small-scale study also provides better understanding of future processes of rocky desertification and the development of rocky desertification at regional scale.

Key words: rocky desertification, landscape pattern, patch size, distribution pattern, object-oriented classification, UAV, classification, bare rates, karst area