Assessing the social context of wildfire-affected areas. The case of mainland Portugal     

《Applied geography (Sevenoaks, England)》2017

Wildfires cause different impacts, depending on the conditions and resilience level of the exposed communities. Wildfire occurrence in mainland Portugal was assessed with regard to socioeconomic and demographic parameters, to identify the most distinctive conditions of fire-affected areas, without implying the existence of causal relationships. The latest population and agriculture census data were used to retrieve conditions at the civil parish level, regarding demographic patterns, social and labor conditions, physical structures and agricultural activities. To identify differences between parishes, two groups were created with the communities that showed the highest and lowest 20% of wildfire incidence between 2007 and 2014, separately for density of fire events and for burned area. A stepwise approach based on classification trees and random Forest methods was applied to identify the best discriminant variables between the groups. First, irrelevant variables were removed by an interactive process based on misclassification rates. The second step used random Forest analysis to the remaining variables to evaluate their importance in distinguishing the groups. In the final step, cluster analysis was applied to test the correspondence between the clusters created with the selected variables and the initial groups. Results showed that parishes with higher fire density have higher population density, higher proportion of young and educated people, larger families and more overcrowded buildings. On the contrary, parishes with larger burned area are less populated, less attractive to foreigners, have a higher proportion of elderly people, more degraded housing conditions and agricultural activities, visible in the density of sheep and goat and pastures, are still relevant. The cluster analysis demonstrated a better performance of the model for wildfire density, revealing a strong association with socioeconomic dynamics with an agreement above 0.85, much higher than for burned areas which is 0.29. Overall, the spatial distribution of wildfire impacts is framed by societal settings and particular conditions must be further understood to improve the coping capacity of affected communities.  相似文献   

移动地图制图的句法模型     

田江鹏  游雄  贾奋励  夏青 《测绘学报》2016,45(11):1352-1360

采用形式语言的方法,研究了移动地图制图的句法模型。剖析了移动地图制图的过程,将句法模型定位在制图的逻辑演算层面;结合地图表达的层次性和递归性特征,将移动地图制图的句法结构抽象为"制图词汇+句法规则"的最简形式。在制图词汇方面,建立了制图词汇的分类体系,并重点对空间关系谓词系统进行了建模;在句法规则方面,描述了句法操作规则和不同层次的句法单位描述规则。探讨了句法模型的编译流程和关键技术,并通过试验对移动地图制图句法模型的可行性进行了验证。句法模型的本质是一种使用有限规则和词汇动态生成不同地图表达形式的形式语言语法,可作为一种高阶的人机交互制图接口。  相似文献   

基于模板的位置地图表达运行机制研究     

袁田  王光霞  周小军  齐晓飞 《测绘工程》2016,25(11):54-59

对位置地图表达模板及表达约束条件进行分析研究,初步设计基于模板的位置地图表达框架。在顾及用户背景信息、地图显示载体信息、情境信息的综合作用下,通过对情境信息进行解析和推理,建立不同地图叠加要素与位置地图要素表达模板的映射关系,并对位置地图表达的触发原理、触发判断和运行机制进行分析研究。  相似文献   

结合全局信息描述子的局部特征匹配算法     

李建磊  王光辉  高宁  丁翠  张海坤 《测绘科学》2016,41(7):33-36,58

针对影像间存在相似性场景时容易出现误匹配的问题,该文提出了局部DAISY描述子与全局纹理信息相结合的算法。详细论述了DAISY描述子和全局纹理的生成过程。该算法首先提取SIFT特征;然后计算特征点的DAISY描述子与全局描述子,获得结合全局信息的DAISY描述子;最后采用卡方统计量作为度量函数进行特征描述子的匹配。实验结果表明,该文算法能得到较好的匹配结果。但是该算法在大角度旋转情况下误匹配率较大。  相似文献   

全球价值链绿色化的概念性认知及其研究框架   总被引：2，自引：0，他引：2  

沈静  曹媛媛 《地理科学进展》2019,38(10):1462-1472

随着全球国际分工的深化和对环境问题的广泛关注,全球价值链的研究框架也成为西方学界研究环境问题中跨区域性、全球-地方联系和环境权力博弈的重要工具。论文将绿色化问题引入全球价值链的分析框架中,在梳理相关文献的基础上,凝练全球价值链绿色化的内涵;并对全球价值链绿色化的驱动机制、全球价值链经济主体的升级带动的绿色化、全球价值链不同治理模式中管理绿色化等基本问题域进行讨论,初步构建全球价值链绿色化的研究框架;并辨析了不同空间尺度下全球价值链绿色化研究的主题和特点;进而提出未来研究需重点关注环境权力关系的界定、绿色化治理的模式以及全球尺度的绿色化网络等方面,旨在为全球价值链下环境问题的分析提供一定的理论依据。  相似文献   

基于图的语义室内导航模型构建研究     

林雕  宋国民  邓晨 《测绘工程》2015,(1):48-52

室内空间模型是室内导航的基础和关键所在,针对当前多数室内空间模型在建模过程中只考虑部分导航相关的影响因素,适用范围有限这一问题,结合室内导航特点,综合考虑用户室内移动特征、几何和语义信息表达、路径规划效率3个方面的建模影响因素,提出一种基于图的语义室内导航模型。基于图论的方法构建室内导航概念模型,然后在概念模型的基础上提出具体的几何图模型构建方法和语义信息表达方式,设计图模型中节点和边的数据结构,最后研究将该模型用于不同情景下室内路径规划的具体流程。  相似文献   

Geodynamic controls on diamond deposits: Implications for Australian occurrences   总被引：1，自引：1，他引：1  

C.J. O'Neill  L. Moresi  A.L. Jaques 《Tectonophysics》2005,404(3-4):217-236

Conventional diamond exploration guidelines predict that economic diamond occurrences will be restricted to Archaean cratons, where the lithosphere is thick and cool, and diamond is the stable form of carbon in the lower portions of the lithosphere. However, Australia's current economic diamond deposits are not well predicted by these conventional exploration guidelines. Tomographic images show that Australia's economic diamond deposits lie at step changes in lithospheric thickness within dominantly cratonized Proterozoic provinces with thick (≥ 200 km) lithosphere. The thickest portions of the seismic lithosphere in Australia occur not under the major Archaean cratons, rather the central Proterozoic regions of the continent. We use a numerical code to show that such features are stable, and that the longevity of the diamond stability field is dependent on distance to the continent–ocean boundary, local depth of the chemical boundary layer (CBL), and proximity to changes in CBL depth. We also show that abrupt changes in lithospheric thickness focus lithospheric stress gradients, affecting melt migration paths, and that continental melt production is enhanced in regions adjacent to major cratons. Diamond pipes occur where conditions conducive to diamond stability and deep-seated alkaline volcanism (kimberlite or lamproite) occur simultaneously, and the common confluence of these factors at abrupt changes in lithospheric thickness marks them as potential exploration targets.  相似文献   

设备场境(DC)在Windows GDI中的应用     

李火亘  周家纪 《物探化探计算技术》1998,(1)

Ｃ＋＋对Ｗｉｎｄｏｗｓ图形设备界面（ＧＤＩ）进行了封装,使得Ｗｉｎｄｏｗｓ环境下的图形开发相当快捷,尤其是它提供的几个设备场境类,使得对图形的操纵更加得心应手。  相似文献   

移动环境自适应地图综合方法初探     

SHEN Jie    LONG Yi    WANG Mei-zhen    SHI Jun-fei 《测绘学院学报》2008,(4)

随着移动定位服务等技术的飞速发展,地图综合在专题内容、综合效率等方面已不能满足移动地图服务的需要。这就要求针对当前的移动环境,发展自适应地图综合方法。在系统分析当今移动环境自适应地图综合研究现状的基础上,指出移动环境自适应地图综合的理论基础与技术背景,提出移动环境自适应地图综合的基本思想、特征与关键问题,并以南京市湖南路商业区居民地为试验数据,实现了自适应于用户位置的居民地简化算法。  相似文献   

意义概念的三个模型     

朱诗勇 《广东海洋大学学报》2007,27(2):14-18

弗雷格首先把意义概念引入分析哲学,其真正目的是坚持思想有公认的确定的正确与错误之分,为思想的客观分析提供基础,但其借助的意义即思想的实体化却有违于这个初衷。直接经验论者从直接经验论立场出发,企图在经验世界中找意义,最后走向否定意义本身,分析哲学由此遭到重创。从语言、思想、世界的关系的高度,把弗雷格的意义理论、观念论、用法论的合理精神结合起来,构建了语境—思想意义模型,认为语言的意义既是主观的东西,同时又具有特殊的客观性:由公共客观的语境决定的确定性。语言的意义就是特定语境中的语言所表达的人们的思想。  相似文献