合轴分枝树木可视化模拟系统设计与实现

以槐树为例,构建了合轴分枝树木可视化模拟系统。根据可视化模拟的需要,指出了所需的形态结构因子及其与IFS因子的对应关系。以实测形态参数数据为依据,结合Logistic生长模型,基于IFS算法构建了槐树的三维模型。并以Direct X9.0为三维可视化平台,使用C#语言,采用面向对象设计思想完成了合轴分枝树木可视化模拟系统开发,实现了合轴分枝树木形态参数、生长模型参数设置以及模型输出等系统功能,较好模拟出合轴分枝树木静态与动态的三维可视化模型。     

国内树木三维可视化技术研究进展

由于树木形态的复杂性对模拟技术和系统开销的要求较高,树木生长的生理确定性和长势不确定性等特点,使树木三维可视化的研究至今仍未得到一个完备的具有林业研究意义的三维计算机树木模型.本文在广泛研究国内树木三维可视化软件开发的基础上,从分形理论、图像解析和GIS技术三个方面对现有研究进行分类阐述,简要叙述了现有研究的主要技术思路与最新研究成果,并指出了现有研究中存在的主要不足.     

国内树木三维可视化研究进展

利用科学的计算方法,将自然界中千变万化的树木形态转换为直观的几何图形,并将其生理结构、生长过程的复杂数据在计算机中进行计算和模拟,称为单株树木的可视化研究.文章介绍了中科院的双尺度自动机模型、浙江大学对于树木的图形图像处理技术的研究以及北京林业大学针对树木生理机构对树木进行的可视化研究.分析了目前树木三维可视化研究中存在的问题,提出了今后的研究方向.     

国内树木三维可视化研究进展

利用科学的计算方法，将自然界中千变万化的树木形态转换为直观的几何图形，并将其生理结构、生长过程的复杂数据在计算机中进行计算和模拟，称为单株树木的可视化研究。文章介绍了中科院的双尺度自动机模型、浙江大学对于树木的图形图像处理技术的研究以及北京林业大学针对树木生理机构对树木进行的可视化研究。分析了目前树木三维可视化研究中存在的问题，提出了今后的研究方向。     

树木虚拟动态生长多因子协同模型及耦合研究综述

在分析树木生长过程正向调控因子和逆向胁迫因子的基础上, 系统综述国内外开展树木虚拟生长研究的4种生长模型, 提出树木生长过程实时感测及多因子协同模型以及基于图像处理的树木病虫害防治模型和树木虚拟动态生长协同模型耦合研究展望, 探讨分析树木虚拟动态生长多因子协同模型耦合、树木虚拟动态生长协同模型与农药喷雾模型耦合等, 可为精确林业关键技术和树木虚拟动态生长技术研究提供参考。     

三维可视化技术在林业中的应用研究进展

阐述三维可视化技术及其在国内外的研究现状.综述了林木可视化、生长模型、林火模拟、森林空间格局4种三维可视化应用方式在林业中的应用研究概况.对三维可视化在林业生产和森林经营管理中的不同应用方式的功能、作用进行了分析概述,并展望了其应用前景.     

农药精确施用模型及其与林木虚拟生长模型协同研究综述

林木虚拟生长模型是应用计算机模拟树木在三维空间中的生长发育状况,而农药精确施用模型是应用计算机模拟农药按需定量喷施、与目标植物接触以及产生药效等一系列喷施作业情况。如果把两者耦合起来,将直观模拟出林木正常生长、受病虫害侵染、农药发挥效果、长势有所好转等一系列交互效果,可为调整植物保护策略、制定农药喷施方案和研制新型植保机械提供理论支持和技术支撑。文中分析了农林病虫害防治情况和农药精确施用的重要性,在综述国内外喷头雾化性能模型、沉降沉积模型（飘移模型）、施药量调节模型、雾化特性预测模型等农药施用模型研究现状的基础上,通过分析探讨两模型协同机理和林木虚拟生长模型及耦合模型实时性协同环境,提出了基于农药施用过程与防治药效的模型协同研究、基于林木形态结构模型的仿形对靶喷雾模型研究以及农药精确施用多模型交互协同研究的建议。     

基于生长规律与图像相结合的树木叶片动态模拟

虚拟树木生长是虚拟植物的一个研究方向,主要研究建立能体现其内在生理特征的生理生态模型和外在表现的可视化模型,是植物学家进行研究的重要工具.     

杉木形态结构可视化模拟调查方法研究

树木可视化模拟首先是树木形态结构的模拟,对树木形态结构的准确了解对于提高模拟精度至关重要。杉木是我国特有的重要用材树种,从杉木可视化模拟的角度出发,针对杉木的形态结构建模所需的参数,从杉木的整体信息和分枝信息两个方面设计了杉木形态结构调查因子,并提出了相应的调查方法。对所调查的杉木数据进行了统计分析,得出了杉木的结构特征:杉木一级枝仰角主要分布在60~°90°内,方位角基本属于均匀分布,二级枝分布在水平方向上;随着枝下距的增加,枝长减少;枝长越长,子枝个数越多。     

杉木人工林抚育间伐可视化模拟技术研究

以湖南省攸县黄丰桥国有林场为试验区、以森林抚育间伐为例、以杉木人工林为主要研究树种,研究森林经营措施的可视化原理和方法,建立了一个面向森林经营管理的虚拟森林原型系统.系统以林业调查数据为数据源,实现虚拟森林漫游、小班属性查询、抚育间伐模拟等功能,为森林资源和森林经营可视化提供了新的平台.     

Design and Implementation of Individual Tree Growth Visualization System of Cunninghamia lanceolata

Nonlinear mixed effects model(NLMEM) is built on the relationship of the fixed and random effects in the regression function.The NLMEM has an obvious comparative advantage in analyzing the longitudinal data,repeated measures data and multilevel data.Two-level NLMEM is used to analyze the dominant height for Chinese fir (Cunninghamia lanceolata).The authors outline the two-level NLMEM and introduce the parameters estimation method of the model.Based on five common Richard and Logistic models,the mixed model is built.The modeling data are used to calculate and compare with 19 models derived from each based model,and 5 optimal mixed models are built.Compared the 5 optimal mixed models with traditional regression models,it is showed that the two-level NLMEM has a better fitting effect than the regression model.     

杉木单木生长可视化模拟系统设计与实现

以杉木为例,采用从可视化模拟角度设计的调查参数调查杉木形态结构,根据实际调查数据对杉木形态结构特征进行了分析。结合生长曲线控制下的迭代函数系统方法,采用面向对象的设计方法,根据DIRECTX9.0提供的API及模型渲染技术,在.NET和DIRECTX9.0平台上,使用C#语言建立了杉木单木生长可视化模拟系统,实现了单株杉木静态和动态的三维可视化模拟。     

森林景观的计算机建模与可视化研究进展

从单棵树的建模、森林场景的绘制技术、森林生长模型分类与特点以及典型的虚拟森林景观系统等几个方面,对森林景观生态的计算机建模和图形可视化研究现状与发展趋势进行综述,就该领域的发展趋势和未来需要解决的关键问题进行总结.     

Design and Realization of 3D Management Information System for Ancient and Famous trees Based on Virtual Plant

The modernization and informatization management of ancient and famous trees’ management is an important standard with which the municipal public resource management level of a region or city can be measured.Design and development of ancient and famous trees’three-dimensional management information system was realized based on virtual plant by using integrated techniques of virtual plants and Geographic Information System.The system architecture design was developed on the basis of functional requirements,and the practical system was achieved in Visual Studio 2008 development tools and OpenGL graphics standards.The system has function of ancient trees archives management,three-dimensional reconstruction of the trees surrounding environment,individual tree information inquiry in three-dimensional scene,etc.Application and dissemination of this system will greatly promote the management and protection of ancient and famous trees standardization,informalization and visualization     

基于形态结构特征的马尾松几何建模研究

以马尾松生长发育的观测数据为依据,提出基于马尾松形态结构特征的交互式几何建模方法,模拟马尾松不同生长发育时期的几何模型.试验证明:这种基于形态结构特征的几何建模技术对模拟和表现马尾松取得了良好的效果.     

Variation in growth potential between hybrid clones of <Emphasis Type="Italic">Eucalyptus</Emphasis> trees in eastern South Africa

Growth of commercial forestry is highly dependent on the availability of fast-growing planting materials. Consequently, the efficient utilization of fast-growing plantations can greatly impact productivity. The objectives of this study were to evaluate variations in the growth potential of two clones and to estimate the average stem radial growth advantage of a fast-growing clone using data obtained from Sappi landholdings in eastern South Africa and a mixed modelling approach that permits the incorporation of covariance structure into the statistical model. During the first 2 years of growth, the stem radius of nine trees each of two clones was measured using dendrometer attached to the tree. A second-degree fractional polynomial model was chosen to show the functional relationship between stem radius and tree age. Growth of the two hybrid clones differed significantly. The Eucalyptus grandis × Eucalyptus urophylla clone grew faster than the E. grandis × camaldulensis clone, indicating better genetic potential for rapid growth and yield. This study can be considered as starting point to further compare the potential for rapid growth of several hybrid clones using the longitudinal data modelling approach.     

Using 3D architectural models to assess light availability and root bulkiness in coconut agroforestry systems

Using 3D architectural models to assess light availability and root bulkiness in agroforestry systems. In many parts of the humid tropics, coconut trees are frequently intercropped with food crops, or tree crops such as cocoa. The performance of such systems depends on planting patterns, but also on growing conditions for crops below the coconut canopy throughout the development of the coconut trees. We used a modelling approach providing indicators for assessing above-ground competition for light and below-ground competition for space, in order to optimize intercropping in coconut smallholdings. Light transmission and the number of coconut roots in the interrow were assessed in coconut smallholdings from 6 to 60 years old. The modelling of light transmission through coconut stands was based on three-dimensional virtual coconut trees and a numerical light model that computed the shade cast by coconut trees on underlying crops. Root colonization in the interrow was assessed with virtual 3D coconut root systems. Our results showed that intercropping with shade-tolerant species was not limited by light transmission from the 35th year after coconut tree planting. However, at that stage of coconut tree development, the density of primary roots in the interrow limited intercrop development, especially for root and tuber crops. Alteration of the planting pattern over time increased light transmission but did not significantly affect root density. This modelling approach, which involved little parameterization that was easily done, appeared to be an efficient tool for recommending coconut tree planting patterns and densities, as well as indicating intercrop potential depending on their location in the most sunlit areas with minimum root competition.

Point process models for mixed sessile forest stands

• Background   

Growth modelling of complex stands calls for the use of spatially explicit single-tree models. Such models require spatially explicit tree locations as the initial state to run simulations. Given the cost of such data, virtual forest stands, where tree locations are simulated, are generally used as the initial state.