USING 3S TECHNOLOGY 
Li Yingcheng 
IN CHINESE INVESTIGATION OF LAND USE CHANGES 
Xue Yanli 
Chinese Academy of Surveying and Mapping 
16 Beitaiping Road, Haidian District, Beijing, China, 100039 
casmrsec(@àsina.com 
Commission VII, WG VII/3 
KEY WORDS: Remote Sensing. GIS. GPS. Land Use. Updating, Statistics 
ABSTRACT: 
Land resources have alternated dynamically due to the national economic development during the last more than 50 vears in China. 
The information on the extent and spatial distribution of various kinds of land use is essential for the decision makers or planners to 
find the rules of changes and take the feasible actions for the optimal development of land usc. So. a project on investigating all kinds 
of land use and making statistic report forms and maps has been kept on by three levels of land use departments which are National 
Land and Resource Department (NLRD). province land departments and county land departments. All of the statistic reports and 
maps should be submitted to NLRD before Oct. 1 each year. 
Because of the poor technology and methods. the original processing flow was tedious, time consuming and expensive. But these 
problems have been improved by integrating GPS. GIS and RS (35) technology recently. This article will introduce several issues 
about using the new technology to carry out land use investigation within a county. One of the key points is how to choose a set of 
data resources feasibly and economically. The next key point is how to use different data resources to find change information in 
doors and check them on the fields. and then five recommended schemes will be given a detailed account in this article. Furthermore. 
an experiment and our own corresponding software package suitable for land use investigation within a county is also introduced at 
the end of the article. 
1. INTRODUCTION 
How to use land resources reasonably and availably is one of 
the most important problems for each country. especially for 
China - the developing and agricultural onc. Chinese 
government carried out a. project. to investigate land-use 
situation around the whole country from 1984 to 1994 in order 
to get real and certain land use statistical data and maps. That 
project had spent almost 10 vears. A serials statistical data had 
been obtained about each spot. every village. every county. 
every province and even the whole country. And also many 
kinds of scale maps had been produced. The maps scale range 
was from 1:10,000 to 1:500.000. The investigation results had 
been very helpful for the government to make decision at that 
time. 
But it is obvious that land is changed dynamically. In order to 
obtain the detail change information during every two years, 
another project had been started up to investigate the land use 
change annually from 1996 till now. 
Most of investigation work was completed manually with the 
common method and technology at that time. It was 
time-consuming and labor intensive. So. a modern method and 
technology is needed to make land use investigated more 
quickly and casily. 
Fortunately. with the development of computer application. 
soltware and internet technology. an advanced land use 
investigation technology has been studied based on GIS, GPS 
and RS integration. This new technology made the job more 
rapidly and efficiently. 
But there are still many problems. for example statistic data 
standard has not been unified to the same format. In order to 
resolve these problems. unified software suitable for Chinese 
county investigation should be studied and developed as soon 
as possible. Data resources selection. RS image 
otho-rectification. change information detected and surveyed 
with GPS. statistic report and land use maps making could be 
integrated together by this new technology and software. 
The main objective of this article is to introduce investigation 
procedure and software using 738" technology. An experiment 
about this technology will be introduced at the end of this 
article. too. 
2. METHOD 
The modern approach of land use investigation includes three 
main steps: (1) change information extracted using RS and GIS 
technology. (2) data collected out of' door using GIS and GPS 
technology. (3) data post-processing using GPS and GIS 
technology. 
2.1 Change Information Detected and Extracted 
Using RS and GIS technology can lessen workload of 
information detection and extraction since large amount of 
changed spots can be detected by computer or interpreted by 
human using remote sensing images. especially when high 
resolution images can be obtained and processed better and 
better now. Generally speaking. when images! geometrical 
resolution is higher than 2.5m like SPOTS. IKONOS and 
QUICKBIRD. and otho-rectified with strict physical model. 
their geometric accuracy can reach the demands of mapping 
scale 1:10000 or larger scale land use map. The main technique 
includes the choice of most suitable data resources. images and 
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