MapGIS明码文件的获取和在坐标转换中的应用研究

MapGIS是我国自主研发的大型地理信息系统软件平台,具有数字制图、空间分析、数据库管理功能,而且MapGIS还支持二次开发。MapGIS有两种数据格式,分别是加密数据文件和明码文件。明码文件可以通过MapGIS平台打开编辑,还可以通过txt、word等文件格式打开、浏览、编辑,这样为MapGIS数据文件的修改提供了多种途径。首先介绍了MapGIS中明码文件的基本特点,并列出了点、线、区、网文件的明码文件的逻辑结构和结构里面包含的信息;然后,重点介绍如何利用点、线、面、区加密文件获取明码文件和将明码文件转换成点、线、面、区加密文件,以及如何利用明码文件在坐标转换中实现平面直角坐标转经纬度坐标。     

曲线坐标系下三维水动力模型求解新方法

为求解三维水动力模型的高精度数值计算,设计了一种在曲线坐标系下求解的新方法.对ξ,η和ζ共3个方向的空间导数分别采用高精度的紧致有限差分以及非线性项的迎风紧致有限差分格式,时间积分则采用四阶修正Runge-Kutta显式格式.为了验证该算法求解曲线坐标系下三维水动力模型的正确性,选取与De Vriend的180°弯道水槽试验相同的物理参数进行数值试验,计算出水位、流速分布等,并将计算结果与De Vriend的试验值以及先前采用SIMPLEC法获得的数值结果进行了对比分析.结果发现：文中创建的高精度算法获得的数值解比SIMPLEC法计算的数值结果更符合试验值,通过算法定量计算得到的平均速度值与试验测量值之间产生的最大相对误差约为3%.说明构建的高精度紧致有限差分算法来数值求解三维水动力问题是可行的、合理的,为天然河道、明渠以及湖泊等水动力计算提供参考依据.     

Topography related spatial distribution of dominant tree species in a tropical seasonal rain forest in China

The degree to which variation in species distribution is predictable from topographic variation is of considerable current interest. In this paper, canonical correspondence analysis (CCA), linear regression and principal coordinates of neighbour matrices (PCNM) models were used to explain the variation in the distributions of the 13 dominant species in a 20-ha tropical rain-forest plot in China. The results showed that: (1) Tree distribution maps show that some species are mainly found in the gullies of the plot, whereas others occur on the slopes. Which indicates topographic variables are important factors for the distribution pattern of species. (2) Both linear regression and CCA results show that convexity and elevation are the most important variables effecting distribution of trees. For saplings, elevation, convexity and aspect explain 15.3%, 9.0% and 10.1% of the total variation of species abundance. For poles, elevation and convexity explain 19.3% and 11.4% respectively. However, only 5.3% of the total variation is explained for adults. (3) The PCNM results showed that topography alone explained 20%, 24% and 5% of the total variation of species abundance for saplings, poles and adults, respectively. Overall evidence for topographic control of the tropical tree distribution is strong, but the explanatory power of topographic variables was a small part of the total of variation.     

我国烤烟育苗的几种主要方式探讨

\t\t\t\t\t目的\t\t\t\t\t为了满足烟苗快速、准确、自动间苗的要求,提出了基于机器视觉的穴盘烟苗自动间苗算法研究,避免传统的人眼观察效率低、随意性大等缺陷。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t采用基于Lab空间下的K-means聚类彩色图像分割算法,根据矩阵行列求和法,在两峰之间取像素坐标,定位其区域位置,把穴盘分割成128个单元格,将目标区域转化为二值图像。通过分别比较烟苗的圆形度、长宽比和矩形度,发现这3种成分的同一形态特征有一定差异,可作单、多株及空穴烟苗识别参数。利用幼苗植株的面积和周长,在不同生长期设定一个合适阈值,实现自动间苗的目的。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t仿真和数据分析表明：取圆形度1.256 6、长宽比1.571 4、矩形度0.716 5的区分效果最好。取面积分布在111~243 (像素),周长分布在16~33 (像素)可以判定为壮苗。在MATLAB R2015a环境下开发了机器视觉烟苗自动间苗软件系统。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t烟苗数目正确识别率达到97.04%以上,空穴位置达到100%,间苗位置及壮苗识别平均准确率分别达到94.76%和89.58%,为进一步开发基于机器视觉的烟苗自动间苗机提供了理论基础和技术支持。\t\t\t\t     

基于地理坐标参数的SAR图像自动概略配准法

提出了一种新的基于地理坐标参数的SAR(Synthetic Aperture Radar)图像自动概略配准方法.该方法利用SAR图像的地理坐标(经纬度)参数,用多项式拟合主辅图像中像元的地理坐标随其图像坐标的变化,首先得到主图像中心像元地理坐标值,然后在辅图像中找到某个像元,其地理坐标等于主图像中心像元的地理坐标,此辅图像中像元的图像坐标与主图像中心像元的图像坐标之差即为概略配准的偏移量.用真实的SAR数据研究证明,本文提出的方法运算速度快,配准精度高.     

基于Cap-cyclide坐标的非圆截面等离子体的稳定性研究

通过导人Cap-cyclide坐标，进行了导体壁对非圆截面等离子体稳定性影响的研究，得出了等离子体的稳定性随着导体壁接近等离子体的表面而增加这一结论。     

浅谈数控车床坐标系及手动对刀方法

对数控车床坐标系和工件坐标系（编程坐标系）进行了分析，针对FANUC OI系统数控车床介绍了一些手动对刀方法，并进行了详细说明。     

公路越岭线选线新思路

在论述公路选线常规手段和方法的基础上 ,提出结合极坐标原理进行越岭线选线的新思路     

Identification of parental species of the Alstroemeria cv. ‘Jubilee’ using AFLP marker technique

Twelve Alstroemeria species, two hybrids, one cv. ‘Jubilee’, an anther-cultured plant from cultivar ‘Jubilee,’ and Bomarea salsilla and Leontochir ovallei (the latter two were chosen as outgroup) were evaluated using the AFLP marker technique in order to identify putative parental genotypes of the Alstroemeria cv. ‘Jubilee’ and of known interspecific hybrids, and to estimate their genetic relationships within the genus Alstroemeria. A total of 297 AFLP markers were scored by using the primer combination (E + ACCA/M + CTAG). In order to discriminate all Alstroemeria genotypes, cluster analysis (UPGMA) and principal coordinates analysis were performed. The Alstroemeria cv. ‘Jubilee’, of which the parents are unknown, had genetic distance (GD) 0.54 from Alstroemeria exserens, GD 0.57 from Alstroemeria garaventae, GD 0.62 from Alstroemeria gayana, and GD 0.66 from Alstroemeria hookeri cumminghiana. Thus, these four species are considered as putative parental genotypes. An interspecific hybrid (Alstroemeria aurea × Alstroemeria inodora), showed the smallest genetic distance from A. aurea (GD 0.56) and A. inodora (GD 0.45). The Alstroemeria ligtu group was distantly allocated from other Chilean species. We conclude that the AFLP marker technique appears to be a satisfactory tool for identifying the parental genotypes of interspecific hybrids in Alstroemeria.     

Soil water movement under a single surface trickle source

Under a trickle source, the flow of water in unsaturated soil takes place from a disc source having a radius changing with time due to change in the rate of infiltration. To predict the wetting pattern below an emitter placed on the soil surface, an unsteady, non-linearised numerical model has been developed in an oblate spheroidal coordinate system. Using this coordinate system, the problem involving disc source geometry having radius changing with time, is simplified, as the disc is a degenerate case of an oblate spheroid. The results of the proposed model are in close agreement with the experimental results of [Taghavi, S.A., Marino, M.A., Rolston, E., 1984. Infiltration from a trickle irrigation source. J. Irrig. Drain. Eng. ASCE 110 (4), 331–341] and the numerical model of [Bresler, E., 1978. Analysis of trickle irrigation with application to design problems. Irrig. Sci. 1, 3–17] developed in cylindrical coordinates. The applicability of the model has been analysed for special conditions of trickle irrigation e.g. large time water application, redistribution of soil water after discharge is cut off or reduced, and basin irrigation with restriction of surface water flow.