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1.
教学理念与教学方法的创新以提高大学生德育教学的质量,作者在教学实践中应用了社会学群体动力理论,提出了教学过程中的两种转换:一是教师身份的转换,即授课者由教师角色转换成班集的群体领袖;二是教育对象的转换,即授课者将教育对象由单个学生组成的班组组织转换整体的班集群体,通过转换,形成良好的群体情境和氛围,从而在教学中发挥群体动力的积极作用。  相似文献   

2.
HNCOOR软件是湖南省测绘坐标转换专用软件,其"湖南大地坐标转换"工具只能接收TXT文件中的坐标数值进行转换,输出仍然为TXT文件,不能直接转换矢量数据。本文以Map GIS 10软件二次开发编程为例介绍一种方法,能提高湖南区域矢量文件的坐标系统转换精度和效率。开发的工具能从矢量文件中自动提取HNCOOR软件能接受的源坐标文本文件,进入HNCOOR软件转换成另一坐标系数据值并输出结果坐标文本文件之后,再由开发形成的工具依照结果坐标文本文件自动将矢量文件的坐标系统转换好,并且不影响矢量文件的属性和符号化参数。  相似文献   

3.
在地图制图工作中需要将CAD数据转换成GIS数据以便于后期的数据处理。文章介绍了通过FME软件将CAD数据中的CAD块、注记、图层、拓展属性等转换成GIS数据的方法,并分析数据的属性类型,设计并优化了合理的数据转换方案,解决了使用传统方法而导致的数据不全、属性混乱、空间位置错乱等问题。  相似文献   

4.
采用高崩溃污染率抗差估计,将GPS网由WGS-84坐标系下的坐标转换成局部坐标系下的坐标,不仅能识别不稳定的地面基准点,而且对所产生的形变大小能作出近于实际的估计,从而保证了求得的坐标转换参数的可靠性。  相似文献   

5.
如何转变专业英语精读课程教学中教师的角色   总被引:5,自引:0,他引:5  
通过对英语专业核心课程——精读课中教师角色在传统和现代教学方法中的对比与分析,探究性地以教学实例论证了教师在精读课程中角色的转换对提高英语专业学生的综合能力起着十分重要的作用。  相似文献   

6.
在日常工作中经常需要将CASS数据转换到MapGis平台中,如果只是简单地将CASS数据转换为通用的DXF格式,再通过MapGis中的文件转换模块转换成MapGis常规形式,那样会存在线形丢失,图元转为线段,甚至文字也成线段的情况,不便于在MapGis中进行编辑和修改。为了能够使CASS数据较为全面和完整地转入MapGis中,笔者总结工作中的经验作以下讨论。  相似文献   

7.
利用不同的解算软件,采用三维七参坐标转换模型和二维四参坐标转换模型,把1980西安坐标系成果转换成2000坐标系成果,利用大量检核点进行坐标转换成果精度检查,并对检查点点位精度做了详细的统计、分析;不仅阐述坐标转换方法和要求,而且得出在2种坐标转换模型应用的条件与要求。  相似文献   

8.
设计了一种基于单片机的电容式液位传感器,主要由单片机系统、555定时器、液晶显示屏组成。单片机作为主要控制的部分,控制系统所有的部分,接收555定时器方波信号并读取出其频率,将频率转换成液位高度,显示到LCD1602液晶显示屏幕上,软件计算液位高度,减小了电容与频率转换的线性误差,最终实现算法的设计。  相似文献   

9.
ArcGIS强大的数据处理与空间分析功能在土地整理中起着关键作用,而在资料收集与外测采集过程中存在大量的CAD数据。把CAD数据转换成GIS数据,并保留完整的图层信息与注释内容则是至关重要的一步。本文以紫阳县旧宅基地腾退为案例详细讲述了CAD数据到GIS数据的转换过程,实践表明这是一种便捷、高效的转换方法。  相似文献   

10.
GRAPES-Meso模式动力框架与物理过程对预报误差影响研究   总被引:1,自引:0,他引:1  
为了研究GRAPES-Meso区域中尺度模式误差特点,评估模式动力框架和物理过程对预报误差的影响重要性,为GRAPES区域集合预报系统方案设计提供参考,基于GRAPES中尺度模式设计了4组对比试验,每组试验对2008年3个不同类型天气过程进行了数值模拟,获得如下结论:(1)GRAPES-Meso模式存在较为显著的系统性误差,系统性误差水平和垂直分布特征主要由GRAPES模式动力框架产生,物理过程对系统性误差影响相对较小;(2)在模式层底和模式层顶,GRAPES模式层与等压面层转换方案中,预报存在较为明显的垂直插值误差;(3)边界层方案对GRAPES模式低层动力场预报误差有重要影响,可以显著减少模式低层动力场预报误差。结果表明减少动力框架预报误差是改进GRAPES-Meso模式的重点,在GRAPES-Meso集合预报系统的设计中,需要重点考虑动力框架引起的模式不确定性。  相似文献   

11.
Dynamics of soil fauna in Da Hinggan Mountains, Northeast China   总被引:1,自引:0,他引:1  
The dynamics of soil animals was studied in seven representative forest communities in the north of the Da Hinggan Mountains, Northeast China. The results indicate that it was distinctive in the changes of the numbers of soil animals and groups and diversity in relationship with seasons for macrofauna and torso-micro fauna in the study area. The numbers of the observed soil animals in different months were: October>August>June. Group number was larger in August and October, but smaller in June. The change of diversity index in different months was: August>June>October. The biomass for macrofanna in different months was: October>June>August. The composition and number of each functional group was relatively stable. In the community of the predominant soil environment, the percentage of saprophagous animals was higher than carnivorous animals and herbivorous animals. The dynamics changes of saprophagous and carnivorous animals were distinctive, increasing from June to October, while the change of herbivorous animals was unremarkable.  相似文献   

12.
Glaciers play an important role in the climate system. The elevation change of a glacier is an important parameter in studies of glacier dynamics. Only a few ground-based measurements of high mountain glaciers are available due to their remoteness, high elevation, and complex topography. The acquisition from the German Tan DEM-X(Terra SAR-X add-on for Digital Elevation Measurement) SAR imaging configuration provides a reliable data sources for studying the elevation change of glaciers. In this study, the bistatic Tan DEM-X data that cover the Geladandong Mountain on the Tibetan Plateau were processed with SAR interferometry technique and the elevation changes of the mountain's glaciers during 2000–2014 were obtained. The results indicated that although distinct positive and negative elevation changes were found for different glacier tongues, the mean elevation change was about-0.14±0.26 m a-1. Geoscience Laser Altimeter System(GLAS) data were obtained for comparison and verification. The investigation using GLAS data demonstrated the efficacy of the proposed method in determining glacier elevation change. Thus, the presented approach is appropriate for monitoring glacier elevation change and it constitutes a valuable tool for studies of glacier dynamics.  相似文献   

13.
基于Google Earth Engine的红树林年际变化监测研究   总被引:1,自引:0,他引:1  
遥感技术已广泛应用于红树林资源调查与动态监测中,但仍然存在遥感数据获取困难、数据预处理工作量大、监测时间长而周期过大等问题,影响了学者对红树林演变过程的精细刻画与理解。本文基于Google Earth Engine(GEE)云遥感数据处理平台,选取Landsat系列卫星数据,生成长时间序列年际极少云影像集(云量少于5%),利用3个红外波段反射率(NIR、SWIR1、SWIR2)和3个特征指数(NDVI、NDWI、NDMI)建立阈值规则集,实现对实验区越南玉显县红树林、红树林-虾塘、不透水面-裸地、水体4种目标地物的专家知识决策树分类和土地覆盖的制图,并基于分类结果监测该区域1993-2017年的红树林年际动态变化。结果表明:GEE平台可满足多云多雨地区红树林的长时间序列年际变化监测需求;本文阈值分类方法可以有效提取红树林及红树林-虾塘,实验区有86%年份的影像分类精度达到80%以上;年际变化监测可精细刻画实验区红树林面积先增后减再增的变化过程,也能准确反映红树林与红树林-虾塘养殖系统面积之间的负相关关系。红树林年际动态监测结果可以降低红树林演变分析的不确定性,并能更精细地量化红树林与其他土地覆盖类型的转化过程,从而评估经济发展、政策等因素对红树林演变的影响。  相似文献   

14.
?????????????н????4??????????????CDP???????????COQ???????????XIC???????????HZH??????5 a?????????????????μ???2007-07??2012-06??ū?Z???????????????????????4??????????仯?????????????????仯??????????????????????????????Z???????????????????????4 a?仯????????????????????JP3????????2???????η??????????С??????????仯????????????????????????????  相似文献   

15.
The landscape pattern of Da'an County, Northeast China has undergone significant changes since the 1950s as a result of climatic change and human activities. The aim of this paper is to quantitatively study landscape pattern and its spatial dynamics of Da'an County at the landscape level over the nearly 50-year span. Patch dynamics were examined according to land use and land cover change processes built from a series of images, as well as topographic maps, and temporal patterns built from landscape pattern metrics. The transition matrix of landscape patch types and changes of various landscape metrics were applied. The results showed that, from 1956 to 2000, the landscape within the study area had undertaken a complicated evolution in landscape structure and composition. The outstanding characteristic is that saline-alkali land increased and grassland decreased. As some smaller patches amalgamated, the heterogeneity of patch decreased. All those changes were the synthetic result of both climatic and anthropogenic influences, but the predominant factor was different in different parts. In the southern part of the study area, the landscape pattern changes resulted from the modification of climate obviously, while in the northern part, the landscape pattern changes were mainly caused by human activities, such as the conversion between farmland and saline-alkali land. This phenomenon showed that human activities played more important role in the north than in the south of Da'an County.  相似文献   

16.
《山地科学学报》2020,17(1):117-132
The climate change and unsustainable anthropogenic modification can intensify the vulnerability of the Himalayas. Natural springs are the principal source of potable water security for the Himalayan population. The changes in the trend of precipitation, temperature and glacier melt are expected to impact the quantity and quality of spring water significantly. This review presents an insight to unravel the effects of climate change and land use land cover changes on the spring resources and outline the essential elements of spring hydrology in the Himalayas. The sensitive response of spring flow to the climate has been observed to follows an annual periodic pattern strongly dependent on snowmelt,rainfall, and evapotranspiration. Among all types,Karst aquifers were found to be highly vulnerable. The changes in the forest and urban landscapes are affecting the recharging sites in the headwater region.In the Central Himalayan region(Kosi River basin,Kumaun), the number of perennial springs is decreasing at a rate of three springs year-1, and nonperennial springs are increasing at the rate of one spring year-1. The high concentration of NO3-, Cl-1,SO42-, and coliform counts reported from the spring water evidence a high susceptibility of shallow aquifers to the non-point source of pollution. Future projections indicate high surface-runoff and occurrence of extreme events such as floods, glacial lake outbursts, and landslides can affect the flow and water quality of springs. As the impact of climate change and anthropogenic activities are expected to increase with time remarkably, there is an urgent need to promote regional scientific studies on springs targeting hydrogeochemical evolution, vulnerability assessment, recharge area dynamics, and development of springshed management program.  相似文献   

17.
The Three Rivers Headwaters Region(TRHR) plays a key role in regulating water supply and climate of East Asia. A comprehensive understanding of the processes and driving forces of the long-term land use dynamics of the TRHR is needed to guide sustainable land resource management and regional ecological conservation strategies. This study examined long-term land change patterns in the TRHR and investigated the driving forces of the change. First, Landsat TM/ETM+ images covering TRHR of four time points from 1987 to 2016 were used to derive land use patterns, and statistical metrics were applied to quantify the spatial and temporal changes. Second, Principal Component Analysis and correlation analysis were employed to analyze environmental and social-economic data to identify the driving forces of land use change. Third, potential influences of the religion of Tibetan Buddhism on land use change were explored using GIS analysis, questionnaire survey and field observation. Results showed that areas of barren land, agricultural land, and built-up land largely increased, while areas of grassland and forest greatly decreased, with the highest change rate occurring in the most recent decade of analysis(from 2007 to 2016). Among the three headwater regions, the Yellow River Headwater Region showed an overall higher changing speed than the other two headwater regions. The regional driving forces of change in TRHR includedsocial-economic development, climatic condition, pressure of population growth, and environmental protection activities. It was also found that Tibetan Buddhism can help slow down the changes caused by human activities.  相似文献   

18.
1 INTRODUCTIONGlobal change research involves much geo-objectsand geo-process, such as climate and environmentalchange, substance and energy cycling, land-use/land-cover change (LUCC), interactivity between human and nature, etc.. So it need cooperation frommany research communities including international research programs groups such as IGBP (InternationalGeosphere-Biosphere Programme IPCC (Intergovemmental Panel on Climate Change), IHDP (InternationalHuman Dimension Program o…  相似文献   

19.
分析丹江口井网3口井水位、水温2013~2015年的观测数据,建立各个测项的正常动态,总结井网对2015-04-25尼泊尔M8.1地震的响应特征,探讨同震响应差异的可能原因,初步得到水位同震响应幅度与震级、井震距的关系。结果表明,井网水位年动态受降雨影响有一定规律,月正常动态普遍显示出固体潮效应与气压效应;水温年动态平稳,年变幅度在0.1 ℃左右。对于尼泊尔地震同震效应,唐扒井水位阶升-阶降式脉冲变化和水温陡降-缓升式脉冲变化是由水位和水温的变化机理不同导致的;雷庄井与唐扒井水位表现出不同的同震响应特征,判断与它们所处断裂的不同走向有关;盛湾井水温阶降型同震响应幅度较唐扒井小得多,可能是观测层岩性及地下水类型等差异导致的。  相似文献   

20.
针对煤矿区植被指数时间序列研究中,存在年际尺度上对植被动态规律刻画不全面、月际尺度上因物候性周期波动导致变化趋势和周期振荡信号微弱难以提取、基于变换的变化检测物理意义不够明确的问题,本文以胜利露天矿区为例,在月际尺度,基于SSA-Mann Kendall重建草原露天矿区的采矿扰动区和伪不变特征区MODIS NDVI时间序列的趋势和周期振荡信号,从显著程度和突变时间2方面对趋势成分进行定量化分析,并结合各特征区周期振荡演变特征揭示采矿扰动下草原露天矿区植被生长的动态规律。结果表明:SSA-Mann Kendall能将NDVI时间序列的微弱信号充分放大,便于提取,并可对趋势成分进行定量化表达,结合周期振荡与趋势成分的演变特征有助于辅助识别矿区植被生长的动态特点;伪不变特征区植被无显著下降趋势,采矿扰动区下降趋势显著,且露天采场较排土场的趋势更为明显,草原露天矿区地表植被损伤具有突发性,突变点多发于矿井开工建设时;扰动形式差异导致部分矿井露天采场和排土场周期振荡演变特征存在差异,露天采场植被消失殆尽,排土场因植被恢复措施而具有更复杂的动态特点。  相似文献   

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