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Microsoft Excel查询和条件函数在林业统计工作中的运用 总被引:1,自引:0,他引:1
针对林业统计工作中Excel的应用现状,论述了利用match查询函数检查小班因子数据表中的重号小班,以及利用Sumif条件函数完成统计表并建立该类型表格模型的方法和步骤.对林业统计工作中应用条件函数能提高统计质量及效率等的优点进行了分析. 相似文献
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针对林业统计数据复杂、核算范围广、数据收集难及指标设计专业性强的特点,从林业统计工作重要性认识不足、林业统计存在数据缺失现象、林业统计基础工作薄弱等3个方面分析了当前河北省林业统计面临的主要问题,并提出要加强对林业统计工作重要性的认识、优化数据质量建设、强化基础管理的对策。 相似文献
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根据四川林业的发展,分析了四川林业经济运行和统计工作现状,指出了林业经济运行的特点,提出进一步拓展林业统计工作的内涵,强化统计工作的决策参考和咨询服务职能。 相似文献
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基于Visual Foxprox6.0软件平台,运用SQL语言,根据森林资源统计报表的特点,进行大型森林资源数据库统计程序的设计。以新疆生产建设兵团为例,分析了该地区的森林资源库结构,根据"乔木林面积、蓄积按龄组统计"报表特点,详细介绍了程序设计的思路及主要程序代码,并进行了该报表的统计。该统计程序能够快速准确生成新疆生产建设兵团的森林资源现状统计报表,为森林资源数据库统计程序的开发提供依据。 相似文献
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野生动物调查统计软件的研制 总被引:1,自引:1,他引:0
编制全国野生动物调查统计软件对于提高对野生动物的科学管理水平、迅速处理分析野生动物的调查数据具有重大意义。本文介绍了该软件的总体设计思想、软件特点及各模块的功能。 相似文献
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基于卫星遥感数据空中抽样的大尺度森林资源动态监测 总被引:1,自引:0,他引:1
为监测大尺度宏观性森林资源动态变化,以SPOT5和ALOS高空间分辨率卫星遥感数据为源数据,辅以相关调查资料,在GIS支持下,采用空中抽样的方法,在遥感图像上布设样地,通过目视判读方法确定样地的土地类型、优势树种(组)等,据此计算森林面积和构造土地类型转移矩阵。根据历史调查资料分析得到森林类型单位面积蓄积量,并以此来计算各类林木蓄积量,从而实现研究区域森林面积、蓄积的动态监测。应用结果表明,在具备高空间分辨率遥感数据以及历史调查资料较丰富的情况下,该方法具有工作量小、精度高,且易于进行动态分析的特点,不但适用于大尺度宏观性森林资源监测,也适用于中尺度(如县级行政区域)的森林资源动态宏观监测。 相似文献
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Quantifying the historical range and variability of landscape composition and structure using simulation modeling is becoming an important means of assessing current landscape condition and prioritizing landscapes for ecosystem restoration. However, most simulated time series are generated using static climate conditions which fail to account for the predicted major changes in future climate. This paper presents a simulation study that generates reference landscape compositions for all combinations of three climate scenarios (warm-wet, hot-dry, and current) and three fire regime scenarios (half historical, historical, and double historical fire frequencies) to determine if future climate change has an effect on landscape dynamics. We applied the spatially explicit, state-and-transition, landscape fire succession model LANDSUM to two large landscapes in west-central Montana, USA. LANDSUM was parameterized and initialized using spatial data generated from the LANDFIRE prototype project. Biophysical settings, critical spatial inputs to LANDSUM, were empirically modeled across the landscape using environmental gradients created from historical and modeled future climate daily weather data summaries. Successional pathways and disturbance probabilities were assigned to these biophysical settings based on existing field data and extensive literature reviews. To assess the impact of changes in climate and fire regime, we compared simulated area burned and landscape composition over time among the different simulation scenario combinations using response variables of Sorenson's index (a global measure of similarity) and area occupied by the dominant vegetation class (simple indicator of change in landscape composition). Results show that simulated time series using future predicted climate scenarios are significantly different from the simulated historical time series and any changes in the fire regime tend to create more dissimilar and more variable simulated time series. Our study results indicate that historical time series should be used in conjunction with simulated future time series as references for managing landscapes. 相似文献
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林业骨干苗圃的建设,是发展“一优二高”林业的物质基础,针对淳安县林业骨干苗圃的建设,科学地确定了建设的原则和规模,并对目前骨干苗圃的建设形式及存在问题提出了一些建议。 相似文献
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历史公园具有历史意义与纪念价值,其发展是城市园林历程的写照。八一公园是南昌历史最为悠久的公园之一,是反映南昌公园发展演变历程最为典型案例。通过史料搜集、复原研究、对比分析等方法梳理八一公园变迁过程,将其分为人文景观逐步形成时期、公园初步建设时期、公园建设曲折发展时期和公园建设接续发展时期4个阶段,指出公园发展受城水互动、政治教化、社会探索、生态实践4个因素推动,呈现古典园林风格到中西融合的风格转变,再到古典园林风格回归的变迁特征。最后总结了城市历史公园景观演变发展动因共性和变迁特征差异性。 相似文献
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Dongwook W. Ko Ashley D. Sparrow Peter J. Weisberg 《Forest Ecology and Management》2011,261(7):1283-1292
Historical processes may have longer lasting effects in arid forest and woodlands because of slow rates of succession. We investigated the influence of historical tree harvesting upon contemporary spatial dynamics of pinyon-juniper woodland in the western United States. Despite intensive and widespread harvesting of woodland by the charcoal industry during the late 19th century, the role of afforestation has seldom been addressed as a potential mechanism for the dramatic expansion of pinyon-juniper woodlands over the past century. Spatial models of disturbance processes are one way to ascertain effects of such historical influences. We developed a process-based spatial model to estimate the historical tree harvest pressure according to a parsimonious set of rules and constraints. The model used a convection-diffusion approach that incorporated the influences of topography, transportation, and mining production. We used a combination of field-surveyed, archaeological, historical, and GIS data sets to calibrate, validate, and compare the alternative mathematical models. Model results were consistent with the historical harvest evidence (AUC > 0.66), with high harvest intensity closer to the mining districts, quickly decreasing at the maximum distance of influence. Performance was improved by including the local terrain. Harvesting initially showed radial patterns emanating from the significant mining districts, and then gradually expanded northward with development of the railway system. Our spatial modeling approach provides a means to assess the pattern and magnitude of historical tree harvesting in semi-arid woodlands. The general approach can be applied to explore the importance of other historical disturbance and cultural processes, whose effects may no longer be evident, in forests and woodlands worldwide. 相似文献