张北县1∶1万大比例尺土地利用遥感调查的试验研究

基于SPOT-5 2.5 m高分辨率遥感影像等数据资料,该文探讨了开展大比例尺土地利用遥感调查的技术路线,进行了张北县大比例尺土地利用遥感调查的试验研究.调查结果表明:2002年张北县土地总面积为424 425.36 hm2,共包括37种土地利用类型,总图斑数是57 193个.其中,旱地、天然草地和有林地分别占全县土地总面积的43.77%、26.31%和7.76%,是该县的主要土地利用类型.与同期1:5万土地利用调查相比,1:1万大比例尺土地利用调查得到的结果更为精确,得到了荒草地、裸土地、裸岩石砾地和苇地等在1:5万土地利用调查中所不能表达的零碎图斑,说明与以往调查相比,该调查结果可以为土地管理决策和进一步的科学研究提供更为准确的信息支持,证明该文设计的应用高分辨率遥感影像进行1:1万土地利用调查的技术路线是正确的,对于今后类似的土地利用调查具有一定的指导意义.但是,通过该试验研究得知,目前试行的<全国土地分类>还不甚完善,为满足大比例尺土地利用遥感调查的要求,<全国土地分类>仍须进一步修订.

Experimental Research to Investigate Present Land Use by Remote Sensing with Large Scale of 1:10 000 in Zhangbei County

Land use is an important driving force not only to the change of natural environment, but also to the development of socio-economic. Therefore, investigation on present land use can play a vital role in providing information to serve the process of making governmental decisions. Based on SPOT-5 images with the pixel size of 2.5 metres and other relevant data, the purposes of this paper is to explore the methodologies of land use investigation by remote sensing with the scale of 1:10 000, and to conduct such an experimental research to investigate the land use in Zhangbei county in 2002. The complete land use investigation is mainly composed of 5 steps that is, in sequence, image geomectric correction (or orthorectification), images fusion, land use classification, image interpretation, and the modification of vector data. In particular, orthorectification and image interpretation are the two most important processes in this research. The results of our investigation indicate that the land area of Zhangbei county is 424425.36 hm2 including 37 categories of land use types and 57193 land use patches in 2002. As 3 main land use types, dry cultivated land, natural grassland and forestland account for 43.77%, 26.31% and 7.76% of the total land area respectively. Compared with another investigation with 1:50 000 scale of Zhangbei land use in 2002, more accurate results were obtained in this one. For example, we digitized many small patches of some land use types, such as barren grassland, bare land, rock and gravel, reed land, which can not be found in the results of 1:50 000 investigation. It is believed that large scale land use investigation with high resolution images, by providing more accurate information, has become an important tool to support governmental land use decisions and further land studies, and that the methodologies presented in this paper is also suitable to the future similar land use investigations. However, some problems were also found in the present from this experimental research. For example, protective forest belt distributed in cultivated land was not clearly classified. In addition, the type of unused land is not defined clearly and logically that occurs two times in the land use classification system. This shows that has to be modified to meet the need of large scale land use investigation with high resolution remote sensing images. Furthermore, we also found that the lack of fundamental geographical maps, such as 1:10 000 relief map, has become an important constraint factors to the coming large scale land use investigations in some counties.