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Digital Change Detection by Post-Classification
Comparison of RS Data in Land Use of Guangzhou
1
Fan Fenglei
1
, Wang Yunpeng
2
, Qiu Maohui
3
1 School of Geography of South China Normal University, Guangzhou (510631)
2 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry,
Guangzhou (510640)
3 College of Environment and Resources, Fuzhou University, Fuzhou (350002)
E-mail:fanfenglei@gig.ac.cn
Abstract
Remote sensing has long time been an important component of regional planning for applications
ranging form urban fringe change detection to monitoring change detection of land use. On the other
hand, the technologies and methods of change detection also have evolved dramatically during past 20
years. So it has been well recognized that the change detection had become the best methods for
researching dynamic change of land use by multi-temporal remotely-sensed data.The purpose of this
paper is to detect land use change surrounding the area of Guangzhou using TM image (Dec 22,1998)
and ETM image (Jan. 10,2003). A county administrative boundary vector layer of the Pearl River Delta
(2000) was used to get the subset image of Guangzhou. Unsupervised classification is performed by the
K_Means method. At last, two-time subset images of Guangzhou are compared on a pixel-by-pixel
basis using the post-classification comparison method and the “from-to” change matrix is produced, the
land use change information obtained.
Keywords: Change detection, Post-classification, land use, Guangzhou
CLC number: F292.2
1. Introduction
The Pearl River Delta is experiencing very fast land use change in recent years along with
rapid economic growth of this region. So there is a great need for governments and researchers to
monitor the rapid change of land use. In early time, the detail land-use drawings were used by
researchers, especially by governments. They usually compared two-time or multi-time land use
data to attempt to find these changes. As the detail land-use drawings are obtained through
fieldwork, the result of land use change is very accurate and each class of land use detailed change
data are also accurate. But as we know, the work of land use fieldwork is performed every 5-10
years, so we can only get old land use data which are not valuable for our present researches.
With the development of RS and GIS, a common method for the detection of land use using
Remote sensing data is accepted and used widely by the public, which is comparing two-time or
multi-time RS images covering the same study area and getting the land use change data. We call
this method change detection which is the process of identifying differences in the state of an
object or phenomenon by observing it at different times (Ashbindu Singh, 1989). Compared with
the fieldwork, these data got by RS images is not so accurate because of the accuracy of images
resolve, images classification and visual interpretation.
Image differencing, vegetation index differencing, selective principal components regression,
image rationing, analysis, direct multi-date classification, univariate image differencing, image
change vector analysis and post-classification were involve in change detection method
(J.F.MAS,1999;Ashbindu Singh, 1989).
A lot of researches of the Pearl River Delta were took based on the conjunction method both
RS and GIS (Qihao Weng, 2002; Xia LI, Anthony Gar-On Yeh,2004; Robert K.Kaufman, Karen
1
This research has been supported by Foundation item of Environmental Sustainability of the Pearl River and
Changjiang Deltas.