rshift.ppp(spatstat)
rshift.ppp()所属R语言包：spatstat
Randomly Shift a Point Pattern
随机一个点转移模式
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Randomly shifts the points of a point pattern.
随机点的点模式转移。
用法----------Usage----------
## S3 method for class 'ppp'
rshift(X, ..., which=NULL, group)
参数----------Arguments----------
参数：X
Point pattern to be subjected to a random shift. An object of class "ppp"
点图案进行随机移位。对象的类"ppp"
参数：...
Arguments that determine the random shift. See Details.
确定的随机漂移的参数。查看详细信息。
参数：group
Optional. Factor specifying a grouping of the points of X, or NULL indicating that all points belong to the same group. Each group will be shifted together, and separately from other groups. By default, points in a marked point pattern are grouped according to their mark values, while points in an unmarked point pattern are treated as a single group.
可选。指定X或NULL，表明所有的点属于同一组的各点的一组因子。每个小组将移位到一起，并分别从其他组。默认情况下，根据自己的标记值进行分组标记点图案的点，而被视为一个单一的点在无人盯防的点模式。
参数：which
Optional. Identifies which groups of the pattern will be shifted, while other groups are not shifted. A vector of levels of group.
可选。标识的格局将被转移组，而其它组无法移动。的向量水平group。
Details
详细信息----------Details----------
This operation randomly shifts the locations of the points in a point pattern.
此操作随机的点图案中的点的位置移位。
The function rshift is generic. This function rshift.ppp is the method for point patterns.
函数rshift是通用的。此功能rshift.ppp点模式的方法。
The most common use of this function is to shift the points in a multitype point pattern. By default, points of the same type are shifted in parallel (i.e. points of a common type are shifted by a common displacement vector), and independently of other types. This is useful for testing the hypothesis of independence of types (the null hypothesis that the sub-patterns of points of each type are independent point processes).
这个函数的最常见的用途是在一个多类型的点模式转移。缺省情况下，点在平行（即通用类型的点是由一个共同的位移矢量偏移），并独立于其他类型的相同类型的偏移。这是非常有用的类型（点每种类型的子模式是独立的点过程的零假设）的独立测试的假设。
In general the points of X are divided into groups, then the points within a group are shifted by a common random displacement vector. Different groups of points are shifted independently. The grouping is determined as follows:
一般来说X点被分成几个组，然后在一组之内的点是由一个共同的随机位移矢量偏移。不同组别的点转向独立。的分组被确定为如下：
If the argument group is present, then this determines the grouping.
如果参数group存在，那么这个决定分组。
Otherwise, if X is a multitype point pattern, the marks determine the grouping.
否则，如果X是一个多类型的点图案，标记的分组。
Otherwise, all points belong to a single group.
否则，所有的点属于一个组。
The argument group should be a factor, of length equal to the number of points in X. Alternatively group may be NULL, which specifies that all points of X belong to a single group.
参数group应该是一个因素，长度相等的点的数量在X。或者group是NULL，其中规定，所有的点X属于一个组。
By default, every group of points will be shifted. The argument which indicates that only some of the groups should be shifted, while other groups should be left unchanged. which must be a vector of levels of group (for example, a vector of types in a multitype pattern) indicating which groups are to be shifted.
默认情况下，每个组将被转移点。参数which表明，只有一些的群体转移，而其它组应保持不变。 whichgroup（例如，在一个多类型图案的类型的矢量）表示该基团是被移位的水平必须为向量。
The displacement vector, i.e. the vector by which the data points are shifted, is generated at random. Parameters that control the randomisation and the handling of edge effects are passed through the ... argument. They are
的位移矢量，即其中的数据点被移位的矢量，是随机生成的。边缘效应的随机控制和处理的参数，通过...参数。他们是
Parameters of the random shift vector.
参数的随机移位矢量。
String indicating how to deal with edges of the pattern. Options are "torus", "erode" and "none".
字符串，指示如何处理模式的边缘。选项"torus"，"erode"和"none"。
Optional. Window to which the final point pattern should be clipped.
可选。窗口的最终模式应该被裁剪。
If the window is a rectangle, the default behaviour is to generate a displacement vector at random with equal probability for all possible displacements. This means that the x and y coordinates of the displacement vector are independent random variables, uniformly distributed over the range of possible coordinates.
如果窗口是一个矩形，默认的行为是随机的概率是相同的所有可能的位移产生的位移矢量。这意味着，x和y是独立随机变量，可能的坐标的范围内均匀地分布在坐标的位移矢量。
Alternatively, the displacement vector can be generated by another random mechanism, controlled by the arguments radius, width and height.
或者，位移矢量可以由另一个随机机制产生，由参数控制radius，width和height。
if width and height are given, then the displacement vector is uniformly distributed in a rectangle of these dimensions, centred at the origin. The maximum possible displacement in the x direction is width/2. The maximum possible displacement in the y direction is height/2. The x and y displacements are independent. (If width and height are actually equal to the dimensions of the observation window, then this is equivalent to the default.)
如果width和height给出的位移矢量均匀分布在这些尺寸的矩形，中心在原点。最大可能的位移x方向是width/2。最大可能的位移y方向是height/2。 x和y位移独立。 （如果width和height实际上等于观察窗的尺寸，那么这相当于默认）。
if radius is given, then the displacement vector is generated by choosing a random point inside a disc of the given radius, centred at the origin, with uniform probability density over the disc. Thus the argument radius determines the maximum possible displacement distance. The argument radius is incompatible with the arguments width and height.
如果radius被给出，则产生的位移矢量，通过选择一个随机的点，以原点为中心的给定半径内的盘在盘，具有均匀的概率密度。这样的话，radius确定可能的最大位移距离。参数radius是不兼容的参数width和height。
The argument edge controls what happens when a shifted point lies outside the window of X. Options are:
参数edge控制一个转向点在于窗外的X时会发生什么。选项有：
Points shifted outside the window of X simply disappear.
点转移窗外X地消失了。
Toroidal or periodic boundary. Treat opposite edges of the window as identical, so that a point which disappears off the right-hand edge will re-appear at the left-hand edge. This is called a “toroidal shift” because it makes the rectangle topologically equivalent to the surface of a torus (doughnut).
环形或周期性的边界。视为相同的治疗窗口的相对边缘，所以，右侧边缘的一个点消失，会重新出现在左手边缘。这就是所谓的“环形移位”，因为它使矩形拓扑相当于一个圆环（圆环）的表面上。
The window must be a rectangle. Toroidal shifts are undefined if the window is non-rectangular.
该窗口必须是一个矩形。环形移位是不确定的，如果该窗口处于非矩形。
Clip the point pattern to a smaller window.
夹点模式到一个较小的窗口。
If the random displacements are generated by a radial mechanism (see above), then the window of X is eroded by a distance equal to the value of the argument radius, using erosion.
如果随机的位移所产生的径向机制（见上文），则该窗口X相等的距离的值的参数radius，使用erosion侵蚀。
If the random displacements are generated by a rectangular mechanism, then the window of X is (if it is not rectangular) eroded by a distance max(height,width) using erosion; or (if it is rectangular) trimmed by a margin of width width at the left and right sides and trimmed by a margin of height height at the top and bottom.
如果随机的位移所产生的矩形的机制，则该窗口X是（如果它是不是矩形）侵蚀的距离max(height,width)使用erosion;或（如果它是矩形）修剪的宽度由边际width在左，右两侧和修剪的高度由边际height的顶部和底部。
The rationale for this is that the clipping window is the largest window for which edge effects can be ignored.
这样做的理由是，在裁剪窗口可以忽略边缘效应是最大的窗口。
The optional argument clip specifies a smaller window to which the pattern should be restricted.
可选参数clip指定一个较小的窗口模式应该加以限制。
值----------Value----------
A point pattern (object of class "ppp").
点模式（类的对象"ppp"）。
（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>
参见----------See Also----------
rshift, rshift.psp
rshift，rshift.psp
实例----------Examples----------
data(amacrine)
# random toroidal shift[随机环形转变的]
# shift "on" and "off" points separately[转向“开”和“关”的点分别]
X <- rshift(amacrine)
# shift "on" points and leave "off" points fixed[转移“的”点，并留下“关闭”点]
X <- rshift(amacrine, which="on")
# shift all points simultaneously[同时将所有点]
X <- rshift(amacrine, group=NULL)
# maximum displacement distance 0.1 units[最大位移距离为0.1个单位]
X <- rshift(amacrine, radius=0.1)
# shift with erosion[转移与侵蚀]
X <- rshift(amacrine, radius=0.1, edge="erode")
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 14:10:37
