基于GIS的丰宁县沙化土地格局分析

Analysis of desertification land patterns in Fengning county based on GIS

以丰宁满族自治县2009年、2014年TM遥感影像数据为信息源,在ArcGIS支持下提取2期沙化数据,采用转移矩阵法和数学模型法分析研究区5a沙化土地格局变化,以2014年土地利用格局为基础,应用CAMarkov模型预测2019年土地利用情况。结果表明:研究区沙化土地集中分布在西部及西南部,以轻度沙化为主,沙化程度总体表现为重度逆转、轻度扩展的趋势,到2014年,重度沙化土地面积减少1 872.8hm^2,重度向中度沙化土地转移概率达0.660 7,中度向轻度沙化土地转移概率为0.635 2;土地利用以林地、草地和耕地为主,林地集中分布在东部并逐渐向西南方向扩展,草地分布在西部地区,耕地夹杂其中,林地和草地间的相互转化是土地主要转移类型;沙化区土地利用类型2009年以草地和耕地为主,随着林地出现和面积的不断增加,中度、重度沙化区演变最为明显;预测2019年土地利用中,林地、未利用地面积继续增加,草地面积不断减少,其他类型变化不明显。

Based on two desertification data extracted with the support of ArcGIS from the remote sensing image of Fengning county in 2009 and 2014,transfer matrix and mathematical model method were used to analyze the change of desertification land pattern in the research region in the past 5 years,and the CA-Markov model was used to predict the land use in 2019 based on the land use pattern in 2014.The results showed that：the desertification land was concentrated in the west and southwestof the research region,mainly in light desertification.The degree of desertification generally showed a severe reversal and a trend of slight expansion.By 2014,the severely desertified area had decreased by 1 872.8 hm-2,the probability of transferring to moderate desertification had reached 0.660 7,and the probability of transferring from moderate to slight desertification had reached 0.635 2.Woodland,grassland and cultivated land were the main land use types;woodland was concentrated in the east and gradually extended to the southwest.Grasslandwas distributed in the west,mixed with cultivated land.The mutual conversion between woodland and grassland was the main type of land transfer.Grassland and cultivated land were the main land use types in desertification area in 2009.With the increase of forest land area,the evolution of moderate and severe desertification area was the most obvious.The area of forest land and unused land would continue to increase,grassland area would decreased,and other types of landwould not change obviously by 2019 forecast.