quadscheme(spatstat)
quadscheme()所属R语言包：spatstat
Generate a Quadrature Scheme from a Point Pattern
从点生成一个正交计划模式
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Generates a quadrature scheme (an object of class "quad") from point patterns of data and dummy points.
产生一个正交计划（类的一个对象"quad"）的数据和虚拟点的点模式。
用法----------Usage----------
quadscheme(data, dummy, method="grid", ...)
参数----------Arguments----------
参数：data
The observed data point pattern. An object of class "ppp" or in a format recognised by as.ppp()
实测数据点的模式。一个对象的类"ppp"的或认可的as.ppp()的格式
参数：dummy
The pattern of dummy points for the quadrature. An object of class "ppp" or in a format recognised by as.ppp() Defaults to default.dummy(data, ...)
用于正交伪点的图案。类的一个对象"ppp"或识别的格式as.ppp()默认值default.dummy(data, ...)
参数：method
The name of the method for calculating quadrature weights: either "grid" or "dirichlet".
正交的权重计算方法的名称是"grid"或"dirichlet"。
参数：...
Parameters of the weighting method (see below) and parameters for constructing the dummy points if necessary.
的加权方法（见下文）和参数构造虚设点，如果必要的参数。
Details
详细信息----------Details----------
This is the primary method for producing a quadrature schemes for use by ppm.
这是主要的方法，用于产生正交计划使用ppm。
The function ppm fits a point process model to an observed point pattern using the Berman-Turner quadrature approximation (Berman and Turner, 1992; Baddeley and Turner, 2000) to the pseudolikelihood of the model. It requires a quadrature scheme consisting of the original data point pattern, an additional pattern of dummy points, and a vector of quadrature weights for all these points. Such quadrature schemes are represented by objects of class "quad". See quad.object for a description of this class.
的功能ppm适合点过程模型的观测点模式，使用伯曼 - 特纳正交近似（Berman和特纳，1992年Baddeley和特纳，2000）的模型pseudolikelihood。它需要一个正交方案组成的原始数据点的图案，哑点的附加图案，和一个正交的权重向量，所有这些点。这种正交计划为代表的对象的类"quad"。见quad.object这一类的描述。
Quadrature schemes are created by the function quadscheme. The arguments data and dummy specify the data and dummy points, respectively. There is a sensible default for the dummy points (provided by default.dummy). Alternatively the dummy points may be specified arbitrarily and given in any format recognised by as.ppp. There are also functions for creating dummy patterns including corners, gridcentres, stratrand and spokes.
正交计划所建立的功能quadscheme。的参数data和dummy指定的数据和虚拟点，分别。默认情况下，虚拟点（提供default.dummy）是一个明智的。或者虚拟任意指定给定在任何认可的as.ppp的格式。还有一些函数创建的虚拟模式，包括corners，gridcentres，stratrand和spokes。
The quadrature region is the region over which we are integrating, and approximating integrals by finite sums. If dummy is a point pattern object (class "ppp") then the quadrature region is taken to be dummy$window. If dummy is just a list of x, y coordinates then the quadrature region defaults to the observation window of the data pattern, data$window.
的正交区域是区域超过我们正在整合，并逼近积分的有限和。如果dummy是一个点的图形对象（类"ppp"）正交区域采取dummy$window。 dummy如果仅仅是一个列表x, y坐标，那么，正交区域的默认设置观察窗的数据模式，data$window。
If dummy is missing, then the optional arguments (for ...) include an argument nd. An nd[1] by nd[2] grid of dummy points is generated by default.dummy.
如果dummy缺失，则可选参数（...）包括一个参数nd。所产生的nd[1]nd[2]default.dummy网格的虚拟点。
If method = "grid" then the optional arguments (for ...) are (nd, ntile). The quadrature region (see below) is divided into an ntile[1] by ntile[2] grid of rectangular tiles. The weight for each quadrature point is the area of a tile divided by the number of quadrature points in that tile.
如果method = "grid"那么的可选参数（例如，...）是(nd, ntile)。该的正交区域（见下文）分为ntile[1]ntile[2]格的矩形砖。每个正交点的权重是正交的点的数目除以在该瓷砖瓷砖的面积。
If method="dirichlet" then the optional arguments are (exact=TRUE, nd). The quadrature points (both data and dummy) are used to construct the Dirichlet tessellation. The quadrature weight of each point is the area of its Dirichlet tile inside the quadrature region. If exact == TRUE then this area is computed exactly using the package deldir; otherwise it is computed approximately by discretisation.
如果method="dirichlet"那么可选的参数是(exact=TRUE, nd)。的正交点（包括数据和伪）被用来构建的Dirichlet镶嵌。正交重量的每个点的面积是其内部的正交区域的Dirichlet瓷砖。如果exact == TRUE那么这方面的精确计算使用包deldir，否则它的离散近似计算。
值----------Value----------
An object of class "quad" describing the quadrature scheme (data points, dummy points, and quadrature weights) suitable as the argument Q of the function ppm() for fitting a point process model.
类的一个对象"quad"描述的积分方案（数据点，虚拟点，和正交权重），适合作为参数Q的功能ppm()拟合点过程模型的。
The quadrature scheme can be inspected using the print and plot methods for objects of class "quad".
积分方案可以通过检查使用对象类print的plot和"quad"方法。
（作者）----------Author(s)----------
Adrian Baddeley
<a href="mailto:Adrian.Baddeley@csiro.au">Adrian.Baddeley@csiro.au</a>
<a href="http://www.maths.uwa.edu.au/~adrian/">http://www.maths.uwa.edu.au/~adrian/</a>
and Rolf Turner
<a href="mailto:r.turner@auckland.ac.nz">r.turner@auckland.ac.nz</a>
参考文献----------References----------
Practical maximum pseudolikelihood for spatial point patterns. Australian and New Zealand Journal of Statistics 42 (2000) 283–322.
Approximating point process likelihoods with GLIM. Applied Statistics 41 (1992) 31–38.
参见----------See Also----------
ppm, as.ppp, quad.object, gridweights, dirichlet.weights, corners, gridcentres, stratrand, spokes
ppm，as.ppp，quad.object，gridweights，dirichlet.weights，corners，gridcentres，stratrand，spokes
实例----------Examples----------
data(simdat)
# grid weights[格的权重]
Q <- quadscheme(simdat)
Q <- quadscheme(simdat, method="grid")
Q <- quadscheme(simdat, nd=50) # 1 dummy point per tile[每瓦1个虚拟点]
Q <- quadscheme(simdat, ntile=25, nd=50) # 4 dummy points per tile[每瓦4假人点]
# Dirichlet weights[狄利克雷重量]
Q <- quadscheme(simdat, method="dirichlet", exact=FALSE)
# random dummy pattern[随机的虚拟模式]
## Not run: [＃不运行：]
D <- runifpoint(250, simdat$window)
Q <- quadscheme(simdat, D, method="dirichlet", exact=FALSE)
## End(Not run)[＃（不执行）]
# polygonal window[多边形窗口]
data(demopat)
X <- unmark(demopat)
Q <- quadscheme(X)
# mask window[面具窗口]
X$window <- as.mask(X$window)
Q <- quadscheme(X)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
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发表于 2012-9-30 14:03:38
