基于空间位置的属性数据连接及对不依比例地物统计的应用研究

本研究着眼于土地利用现状调绘不依比例地物的精确统计,围绕着基于空间位置的属性连接方法的应用,利用MapGIS、AutoCAD、CASS和MapGIS土地利用数据库管理系统等软件展开了分析。探讨了空间位置的属性连接方法的理论基础与实施步骤,并提出了空间数据的质量控制与检查的对策。在此基础之上,通过对同一测绘对象分别使用传统方法和基于空间位置的属性连接方法进行了统计,对两种方法的统计结果进行了对比。证实了基于空间位置属性连接方法能够更有效地提高空间数据统计的精度和速度。     

生态建设对陕北植被变化的影响分析

运用趋势分析法及相关系数检验法,分析了陕北大规模生态建设工程实施以来植被NDVI变化趋势,检验了NDVI变化与降雨量、温度以及造林面积之间的关系。结果表明:陕北大部分地区植被明显转好(通过α=0.05检验),尤其是丘陵沟壑农耕区植被改善最为显著,12 a间NDVI净增0.123 3,提高24.90%,南部森林植被区,NDVI净增最低,只有0.045 0,增加率5.56%。NDVI变化格局与生态退耕格局在空间上呈现高度吻合的特征。NDVI变化与降雨量和温度没有显著的回归关系(R20.15),但与造林率(造林面积占县土地面积的比)回归关系显著(R2=0.560 8),说明降雨量、温度变化对陕北NDVI变化没有明显的影响,而以退耕和植树造林为主的生态建设才是导致NDVI变化的主导因素。结论认为过去12 a的生态建设明显促进了陕北植被的恢复,改善了区域环境状况。     

陕北黄土丘陵区干燥度变化趋势及其对植被恢复的响应(英文)

Detecting variation trend in dry-wet conditions can provide information for developing strategic measures to mitigate the impacts of global warming, particularly in dry regions. Taking the hilly region of northern Shaanxi on the Loess Plateau as a case area, this study analyzed the trend of aridity variation during 1981–2012, and explored the effect of vegetation restoration promoted by the Grain-for-Green(GFG) program implemented in 1999. The results indicated that the aridity in the region was non-significantly increased by 0.88% per year during 1981–2012, showing a drying trend. This drying trend and amplitude were changed by the influence of vegetation restoration promoted by the GFG program, based on two findings. The first one was that the aridity variation tended to increase during 1981–1999 while it turned to decrease during 2000–2012, with the regional mean relative change rate changed from 2.45% to –1.06%. This distinction was more remarkable in the loess gully region, where the vegetation was improved more obviously. The second one was that the mean vegetation coverage as indicated by EVI increased by 0.90% to 4.32% per year at county level, while the aridity decreased by 0.14% to 2.32% per year during 2000–2012. The regression analysis using the mean county data indicated that the change rate of aridity was negatively related to that of EVI with the coefficient of determination(R2) of 0.56, illustrating that around half of the aridity decline was explained by the EVI change. The mechanism of this effect was complicated, but it was found that the wind speed decline induced by the vegetation improvement could be an important contributor. It is concluded that the region became drier during 1981–2012, but the eco-restoration reduced the drying speed. However, this conclusion is involved in uncertainties, and further study based on experiments is needed to confirm the effect of the GFG-promoted vegetation restoration.     

城乡建设用地增减挂钩的利弊分析

本文剖析了城乡建设用地增减挂钩政策的内涵、操作方法，阐述了政策的目的和意义，通过分析挂钩政策的优势及其存在的问题和隐患，提出在增减挂钩项目实施过程中，应该协调好城乡关系，注意保护好农村利益，同时避免为了取得城镇建设用地指标，只注重耕地数量而忽视耕地质量保护现象发生。