GPS RTK的工作原理及在公路工程中的应用浅析     

王皓衍 《林业科技情报》2007,39(3):113-113,115

本文结合近几年的工程应用介绍了GPS RTK(Real Time Kinematic)工作原理及其在实际公路工程中的应用,对其在公路工程中的优越性,作业方法等进行简单的介绍.  相似文献   

基于R2V与ArcInfo的地形图数字化方法   总被引：3，自引：4，他引：3  

包忠聪  岳彩荣  何超 《林业调查规划》2006,31(5):29-32

结合R2V和ArcInfo 2种应用工具,阐述数字化地形图的新方法。Workstation下精妙的算法可以很好地解决图像校正精度以及图像拼接问题。利用R2V可以实现半自动化数字化。通过二者的结合使用,实现优势互补,完成地形图的高效数字化。  相似文献   

黄土高原小流域土壤养分空间特征及其与地形因子的相关性   总被引：1，自引：0，他引：1  

杨建虎  常鸿莉  魏琪 《西北农林科技大学学报(自然科学版)》2014,42(12):85-91

【目的】分析黄土高原地区小流域内土壤养分含量的空间特征及其与地形因子的相关性,为养分精确管理和土地资源高效利用提供参考依据。【方法】以位于黄土高原的陕西彬县红岩河小流域为例,于2011年结合GPS共采集了121个田间土样,对其土壤养分(有机质、碱解氮、速效磷、有效钾)含量进行测定,并应用地统计学方法对土壤养分含量半方差函数模型及其参数进行了确定,用普通克里格插值(Kriging)绘制了研究区土壤养分空间分布图,统计分析高程、坡度、坡向、坡形等地形因子与土壤养分含量的相关性,并进行了插值结果检验。【结果】陕西彬县红岩河小流域土壤碱解氮的空间变异性很弱,有机质、速效磷和有效钾具有强烈的空间变异性。各养分含量空间分布均呈斑块状,条带性分布趋势不明显。总体上土壤有机质和速效养分含量与高程和坡度呈负相关,与坡向呈正相关,与坡形相关不显著。【结论】随机性变异(人为因素)对碱解氮的空间变异起主导作用,且变程较小,有机质、速效磷和有效钾的空间变异主要由结构性变异(自然因素)引起,且变程较大。高程、坡度及坡向明显影响土壤养分的含量和分布。  相似文献   

Final Analysis of the Accuracy and Precision of Methods to Calculate the Sediment Retained by Check Dams     

《Land Degradation \u0026amp; Development》2017,28(8):2446-2456

Knowing how much sediment check dams have trapped during their lifespan is essential to estimate their effectiveness or the sediment yields of their basins. Methods to calculate the volume of sediment trapped by check dams play an important role in the understanding of these issues. Several authors have proposed different methods to measure the volume of retained sediment, but their accuracy has, as yet, not been precisely determined and is currently a subject of debate. We compare the most frequently used methods (geometric: prism, pyramid and geometric; topographic: Digital Terrain Models (DTMs), trapezoids and sections methods) to evaluate their accuracy and precision in determining the volume of sediment retained by check dams. Our calculations are based on ten virtual check dams simulated in several gullies of Saldaña (Spain), where we determine their volumetric capacity for trapping sediment (real volume). This was made by means of an intensive topographic survey of these gullies, employing a terrestrial laser scanning system to obtain a high‐resolution digital elevation model (5 × 5 cm, ±2 mm). The results showed that topographic methods provided a very good fit to real volume with a difference of around 8%, being the sections method the most accurate. Geometric methods were less accurate, showing differences of up to 28%. Thus, the results obtained until now by geometric methods should be considered with caution. Although topographic methods were more accurate, they require many field data and much time than the others. So geometric methods can still be useful by correcting their results using our obtained percentage of variation. Knowing the accuracy of the methods before measuring is essential to obtain the most reliable results to analyse the role of check dams in controlling sediment, erosion processes and land degradation. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Examining brain oedema through brain electrical impedance topographic mapping     

LUO Ci-yong  ZHANG Zhan-long  HE Wei 《保鲜与加工》2004,(8):43-46

Change of Brain Electrical Impedance has great relations with brain oedema and brain block, a new method of Examining Brain Oedema through Brain Electrical Impedance Topographic Mapping(BEITM)is reviewed. Network topology structure that used in BEITM are also presented. According to topology, we discuss the drawing algorithm that based on triangle element. Some patients have been measured to make clinical data, according to this data Brain Electrical Impedance topographic come into being by computer at last, functional imaging has been implemented. Clinical case analysis compared with change state of an illness and repeatability of steady patient's data has proved the method is feasible.  相似文献   

基于全球导航卫星系统的智能化精细平地系统优化与试验   总被引：1，自引：2，他引：1  

李笑  李宏鹏  牛东岭  王岩  刘刚 《农业工程学报》2015,31(3):48-55

农田土地精细平整是中国现代地面精细灌溉的重要基础,能提高农田灌溉均匀度,改良土壤水盐分布,控制杂草,达到节水增产的效果。应用GNSS(global navigation satellite system,全球导航卫星系统)技术进行土地精细平整具有不受天气影响、测量速度快、工作效率高等优点,具有广泛应用前景。该文结合中国土地平整的实际情况和前期的研究成果,开发了适合国内应用的GNSS控制平地系统,降低了研发的设备成本,优化完善了平地系统的功能。为减少分立设备数量,提高系统集成度,设计了集成控制终端,集成GNSS接收模块、差分电台模块、核心处理平台和阀控制模块,并设计了集成控制终端的外壳,通过可旋转调整支架固定在拖拉机驾驶室内,具有良好的防尘、降温和牢固等优点;为完善地形测量功能,增加了测量轨迹的实时显示,以及农田面积等地势信息的计算,便于指导后续平整作业;优化了基准设计,建立了坡面平整的数学模型,实现了任意坡度坡面平整。优化后的系统主要由集成控制终端、自主差分GNSS接收设备、液压系统以及平地铲运设备几部分构成;以Visual Studio2008为系统软件开发环境,GNSS精细平整集成软件能够实现农田地势测量、基准设计及平整作业等功能。该智能平地系统在中国农业大学上庄试验站进行了长时间平整实验,平面平整后最大高程差从20.9降到10.5 cm,高程标准差从10.6降到5.5 cm,平地误差小于5 cm的测点累积百分比从77%上升到90%左右,平整效果良好。坡面平整的坡度从0.239%降到0.120%,符合设计要求。结果表明,系统工作稳定可靠,作业精度满足土地精细平整要求,适用于在中国推广应用。  相似文献   

广东省1992-2015年土地覆被变化的时空差异及其成因     

顾慧  唐国平  江涛  方宏  唐纤蕴  陈晓桦 《水土保持通报》2020,40(2):291-298

[目的] 从地形和社会经济两个因素出发探讨广东省土地覆被变化的时空差异及成因，为土地资源的可持续利用提供依据。[方法] 基于1992-2015年间广东省土地覆被数据，使用土地利用动态度、土地利用转移矩阵、灰色关联分析等方法量化土地覆被变化的时空特征与差异。[结果] 广东省土地覆被变化以2000年为节点可分为前期（1992-2000年）和后期（2000-2015年）两个阶段。前期耕地面积显著增加，建筑用地面积增速缓慢；后期耕地面积减小，建筑用地面积扩张迅速。地形因素造成土地覆被变化存在空间差异性。在高程低，坡度缓的区域土地覆被变化主要是耕地转化为建筑用地，而在坡度中等区域主要是林地转为耕地。社会经济因素造成土地覆被变化呈现较明显时间差异性，多种因子驱动广东省土地覆被发生变化。但对于不同的土地覆被类型，驱动因子前后期的关联度大小不同，土地覆被发生变化是多种因子驱动叠加的结果。[结论] 地形因素会造成土地覆被变化的空间差异，而社会经济因素导致土地覆被变化的时间差异。  相似文献   

航空遥感技术在林改宗地勘界中的研究与应用     

邹杰 《绿色科技》2011,(12)

指出了在集体林权制度改革中,林地宗地勾绘是核心内容,分析了采用高分辨率大比例尺航空正射影像图与电子矢量化地形图叠加进行林改宗地勘界,研究表明：其技术比传统地形图上勾绘宗地方法更能提高工作效率及勾绘精度。  相似文献   

Spatial variation in organic carbon, nutrients and microbial biomass contents of paddy soils in a hilly red soil region   总被引：1，自引：0，他引：1  

Guoyong Tang  He’ai Xiao  Yirong Su  Daoyou Huang  Shoulong Liu  Min Huang  Chengli Tong  Jinshui Wu 《Frontiers of Agriculture in China》2007,1(4):424-429

The contents of soil organic C (SOC), total N (TN), total P (TP), dissolved N (D_N), Olsen-P, and microbial biomass C, N, P (B_C, B_N, B_P) of 254 paddy soils (0–18 cm in depth) in a hilly red soil region of subtropical zone of China were studied. The results showed that the contents of SOC, TN, B_C, B_N and D_N of paddy soils at the bottom of hills were 14.6%, 13.6%, 24.6%, 20.4% and 95.8% higher than those at the foothill, respectively. The Olsen-P content of paddy soils at the foothill was 33.3% higher than that at the bottom of hills. However, the differences in TP, B_P and available P (the sum of B_P and Olsen-P) contents were not significant between the two positions. In addition, the ratios of soil C/P, B_C/B_P and B_C/SOC of paddy soils at the bottom of hills were 12.7%, 28.5% and 8.2% higher than those at the foothill, respectively, but the differences in ratios of soil C/N, B_C/B_N, B_N/TN and B_P/TP were not statistically significant between various positions. __________ Translated from Plant Nutrition and Fertilizer Science, 2007, 13(1): 15–21 [译自: 植物营养与肥料学报]  相似文献   

对提高林业成图质量问题的探索     

尹关聪 《浙江林学院学报》1991,8(3):405-407

应用遥感技术编制的林业遥感影像图是一种很理想的林业图,但成图费用太高,林业部门本身又缺乏成图仪器,要推广使用受到限制。结合外业调查的航空像片,以1:10000比例尺地形图为底图绘制林业基本图,是一种多、快、好、省的方法,适用于基层林业单位推广应用。  相似文献