R插值极坐标图 [英] R interpolated polar contour plot
本文介绍了R插值极坐标图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试根据插值点数据编写R中的轮廓极坐标图.换句话说，我的极坐标中的数据具有要绘制和显示插值的幅度值.我想批量生产类似于以下内容的图(由OriginPro生成):
I'm attempting to script a contour polar plot in R from interpolated point data. In other words, I have data in polar coordinates with a magnitude value I would like to plot and show interpolated values. I'd like to mass produce plots similar to the following (produced in OriginPro):
到目前为止，我在R中最接近的尝试是:
My closest attempt in R to this point is basically:
### Convert polar -> cart
# ToDo #
### Dummy data
x = rnorm(20)
y = rnorm(20)
z = rnorm(20)
### Interpolate
library(akima)
tmp = interp(x,y,z)
### Plot interpolation
library(fields)
image.plot(tmp)
### ToDo ###
#Turn off all axis
#Plot polar axis ontop
哪个会产生类似以下内容的信息:
Which produces something like:
虽然这显然不是最终产品，但这是在R中创建轮廓极坐标图的最佳方法吗?
While this is obviously not going to be the final product, is this the best way to go about creating contour polar plots in R?
除了存档邮件列表之外，我在该主题上找不到其他内容 Python示例).
I can't find anything on the topic other than an archive mailing list dicussion from 2008. I guess I'm not fully dedicated to using R for the plots (though that is where I have the data), but I am opposed to manual creation. So, if there is another language with this capability, please suggest it (I did see the Python example).
关于使用ggplot2的建议-我似乎无法获得geom_tile例程来在Polar_coordinates中绘制插值数据.我在下面包含了说明我所处位置的代码.我可以用笛卡尔坐标和极坐标绘制原始图形，但只能获取插值数据以笛卡尔坐标绘制.我可以使用geom_point在极坐标中绘制插值点，但是无法将这种方法扩展到geom_tile.我唯一的猜测是，这与数据顺序有关-即geom_tile期望排序/排序的数据-我已经尝试过每一次迭代，我都能想到将数据排序为升/降方位角和天顶，而无需更改.
Regarding the suggestion using ggplot2 - I can't seem to get the geom_tile routine to plot interpolated data in polar_coordinates. I have included code below that illustrates where I'm at. I can plot the original in Cartesian and polar, but I can only get the interpolated data to plot in Cartesian. I can plot the interpolation points in polar using geom_point, but I can't extend that approach to geom_tile. My only guess was that this is related to data order - i.e. geom_tile is expecting sorted/ordered data - I've tried every iteration I can think of sorting the data into ascending/descending azimuth and zenith with no change.
## Libs
library(akima)
library(ggplot2)
## Sample data in az/el(zenith)
tmp = seq(5,355,by=10)
geoms <- data.frame(az = tmp,
zen = runif(length(tmp)),
value = runif(length(tmp)))
geoms$az_rad = geoms$az*pi/180
## These points plot fine
ggplot(geoms)+geom_point(aes(az,zen,colour=value))+
coord_polar()+
scale_x_continuous(breaks=c(0,45,90,135,180,225,270,315,360),limits=c(0,360))+
scale_colour_gradient(breaks=seq(0,1,by=.1),low="black",high="white")
## Need to interpolate - most easily done in cartesian
x = geoms$zen*sin(geoms$az_rad)
y = geoms$zen*cos(geoms$az_rad)
df.ptsc = data.frame(x=x,y=y,z=geoms$value)
intc = interp(x,y,geoms$value,
xo=seq(min(x), max(x), length = 100),
yo=seq(min(y), max(y), length = 100),linear=FALSE)
df.intc = data.frame(expand.grid(x=intc$x,y=intc$y),
z=c(intc$z),value=cut((intc$z),breaks=seq(0,1,.1)))
## This plots fine in cartesian coords
ggplot(df.intc)+scale_x_continuous(limits=c(-1.1,1.1))+
scale_y_continuous(limits=c(-1.1,1.1))+
geom_point(data=df.ptsc,aes(x,y,colour=z))+
scale_colour_gradient(breaks=seq(0,1,by=.1),low="white",high="red")
ggplot(df.intc)+geom_tile(aes(x,y,fill=z))+
scale_x_continuous(limits=c(-1.1,1.1))+
scale_y_continuous(limits=c(-1.1,1.1))+
geom_point(data=df.ptsc,aes(x,y,colour=z))+
scale_colour_gradient(breaks=seq(0,1,by=.1),low="white",high="red")
## Convert back to polar
int_az = atan2(df.intc$x,df.intc$y)
int_az = int_az*180/pi
int_az = unlist(lapply(int_az,function(x){if(x<0){x+360}else{x}}))
int_zen = sqrt(df.intc$x^2+df.intc$y^2)
df.intp = data.frame(az=int_az,zen=int_zen,z=df.intc$z,value=df.intc$value)
## Just to check
az = atan2(x,y)
az = az*180/pi
az = unlist(lapply(az,function(x){if(x<0){x+360}else{x}}))
zen = sqrt(x^2+y^2)
## The conversion looks correct [[az = geoms$az, zen = geoms$zen]]
## This plots the interpolated locations
ggplot(df.intp)+geom_point(aes(az,zen))+coord_polar()
## This doesn't track to geom_tile
ggplot(df.intp)+geom_tile(aes(az,zen,fill=value))+coord_polar()
最终结果
我终于从可接受的答案(基本图形)中获取了代码并更新了代码.我添加了薄板样条曲线插值方法，是否可以推断的选项，数据点覆盖图以及为插值曲面执行连续颜色或分段颜色的功能.请参见下面的示例.
Final Results
I finally took code from the accepted answer (base graphics) and updated the code. I added a thin plate spline interpolation method, an option to extrapolate or not, data point overlays, and the ability to do continuous colors or segmented colors for the interpolated surface. See the examples below.
PolarImageInterpolate <- function(
### Plotting data (in cartesian) - will be converted to polar space.
x, y, z,
### Plot component flags
contours=TRUE, # Add contours to the plotted surface
legend=TRUE, # Plot a surface data legend?
axes=TRUE, # Plot axes?
points=TRUE, # Plot individual data points
extrapolate=FALSE, # Should we extrapolate outside data points?
### Data splitting params for color scale and contours
col_breaks_source = 1, # Where to calculate the color brakes from (1=data,2=surface)
# If you know the levels, input directly (i.e. c(0,1))
col_levels = 10, # Number of color levels to use - must match length(col) if
#col specified separately
col = rev(heat.colors(col_levels)), # Colors to plot
contour_breaks_source = 1, # 1=z data, 2=calculated surface data
# If you know the levels, input directly (i.e. c(0,1))
contour_levels = col_levels+1, # One more contour break than col_levels (must be
# specified correctly if done manually
### Plotting params
outer.radius = round_any(max(sqrt(x^2+y^2)),5,f=ceiling),
circle.rads = pretty(c(0,outer.radius)), #Radius lines
spatial_res=1000, #Resolution of fitted surface
single_point_overlay=0, #Overlay "key" data point with square
#(0 = No, Other = number of pt)
### Fitting parameters
interp.type = 1, #1 = linear, 2 = Thin plate spline
lambda=0){ #Used only when interp.type = 2
minitics <- seq(-outer.radius, outer.radius, length.out = spatial_res)
# interpolate the data
if (interp.type ==1 ){
Interp <- akima:::interp(x = x, y = y, z = z,
extrap = extrapolate,
xo = minitics,
yo = minitics,
linear = FALSE)
Mat <- Interp[[3]]
}
else if (interp.type == 2){
library(fields)
grid.list = list(x=minitics,y=minitics)
t = Tps(cbind(x,y),z,lambda=lambda)
tmp = predict.surface(t,grid.list,extrap=extrapolate)
Mat = tmp$z
}
else {stop("interp.type value not valid")}
# mark cells outside circle as NA
markNA <- matrix(minitics, ncol = spatial_res, nrow = spatial_res)
Mat[!sqrt(markNA ^ 2 + t(markNA) ^ 2) < outer.radius] <- NA
### Set contour_breaks based on requested source
if ((length(contour_breaks_source == 1)) & (contour_breaks_source[1] == 1)){
contour_breaks = seq(min(z,na.rm=TRUE),max(z,na.rm=TRUE),
by=(max(z,na.rm=TRUE)-min(z,na.rm=TRUE))/(contour_levels-1))
}
else if ((length(contour_breaks_source == 1)) & (contour_breaks_source[1] == 2)){
contour_breaks = seq(min(Mat,na.rm=TRUE),max(Mat,na.rm=TRUE),
by=(max(Mat,na.rm=TRUE)-min(Mat,na.rm=TRUE))/(contour_levels-1))
}
else if ((length(contour_breaks_source) == 2) & (is.numeric(contour_breaks_source))){
contour_breaks = pretty(contour_breaks_source,n=contour_levels)
contour_breaks = seq(contour_breaks_source[1],contour_breaks_source[2],
by=(contour_breaks_source[2]-contour_breaks_source[1])/(contour_levels-1))
}
else {stop("Invalid selection for \"contour_breaks_source\"")}
### Set color breaks based on requested source
if ((length(col_breaks_source) == 1) & (col_breaks_source[1] == 1))
{zlim=c(min(z,na.rm=TRUE),max(z,na.rm=TRUE))}
else if ((length(col_breaks_source) == 1) & (col_breaks_source[1] == 2))
{zlim=c(min(Mat,na.rm=TRUE),max(Mat,na.rm=TRUE))}
else if ((length(col_breaks_source) == 2) & (is.numeric(col_breaks_source)))
{zlim=col_breaks_source}
else {stop("Invalid selection for \"col_breaks_source\"")}
# begin plot
Mat_plot = Mat
Mat_plot[which(Mat_plot<zlim[1])]=zlim[1]
Mat_plot[which(Mat_plot>zlim[2])]=zlim[2]
image(x = minitics, y = minitics, Mat_plot , useRaster = TRUE, asp = 1, axes = FALSE, xlab = "", ylab = "", zlim = zlim, col = col)
# add contours if desired
if (contours){
CL <- contourLines(x = minitics, y = minitics, Mat, levels = contour_breaks)
A <- lapply(CL, function(xy){
lines(xy$x, xy$y, col = gray(.2), lwd = .5)
})
}
# add interpolated point if desired
if (points){
points(x,y,pch=4)
}
# add overlay point (used for trained image marking) if desired
if (single_point_overlay!=0){
points(x[single_point_overlay],y[single_point_overlay],pch=0)
}
# add radial axes if desired
if (axes){
# internals for axis markup
RMat <- function(radians){
matrix(c(cos(radians), sin(radians), -sin(radians), cos(radians)), ncol = 2)
}
circle <- function(x, y, rad = 1, nvert = 500){
rads <- seq(0,2*pi,length.out = nvert)
xcoords <- cos(rads) * rad + x
ycoords <- sin(rads) * rad + y
cbind(xcoords, ycoords)
}
# draw circles
if (missing(circle.rads)){
circle.rads <- pretty(c(0,outer.radius))
}
for (i in circle.rads){
lines(circle(0, 0, i), col = "#66666650")
}
# put on radial spoke axes:
axis.rads <- c(0, pi / 6, pi / 3, pi / 2, 2 * pi / 3, 5 * pi / 6)
r.labs <- c(90, 60, 30, 0, 330, 300)
l.labs <- c(270, 240, 210, 180, 150, 120)
for (i in 1:length(axis.rads)){
endpoints <- zapsmall(c(RMat(axis.rads[i]) %*% matrix(c(1, 0, -1, 0) * outer.radius,ncol = 2)))
segments(endpoints[1], endpoints[2], endpoints[3], endpoints[4], col = "#66666650")
endpoints <- c(RMat(axis.rads[i]) %*% matrix(c(1.1, 0, -1.1, 0) * outer.radius, ncol = 2))
lab1 <- bquote(.(r.labs[i]) * degree)
lab2 <- bquote(.(l.labs[i]) * degree)
text(endpoints[1], endpoints[2], lab1, xpd = TRUE)
text(endpoints[3], endpoints[4], lab2, xpd = TRUE)
}
axis(2, pos = -1.25 * outer.radius, at = sort(union(circle.rads,-circle.rads)), labels = NA)
text( -1.26 * outer.radius, sort(union(circle.rads, -circle.rads)),sort(union(circle.rads, -circle.rads)), xpd = TRUE, pos = 2)
}
# add legend if desired
# this could be sloppy if there are lots of breaks, and that's why it's optional.
# another option would be to use fields:::image.plot(), using only the legend.
# There's an example for how to do so in its documentation
if (legend){
library(fields)
image.plot(legend.only=TRUE, smallplot=c(.78,.82,.1,.8), col=col, zlim=zlim)
# ylevs <- seq(-outer.radius, outer.radius, length = contour_levels+ 1)
# #ylevs <- seq(-outer.radius, outer.radius, length = length(contour_breaks))
# rect(1.2 * outer.radius, ylevs[1:(length(ylevs) - 1)], 1.3 * outer.radius, ylevs[2:length(ylevs)], col = col, border = NA, xpd = TRUE)
# rect(1.2 * outer.radius, min(ylevs), 1.3 * outer.radius, max(ylevs), border = "#66666650", xpd = TRUE)
# text(1.3 * outer.radius, ylevs[seq(1,length(ylevs),length.out=length(contour_breaks))],round(contour_breaks, 1), pos = 4, xpd = TRUE)
}
}
推荐答案
[[主要修改]] 我终于能够在最初的尝试中添加轮廓线，但是由于扭曲的原始矩阵的两侧实际上并未接触，因此这些线在360度和0度之间不匹配.所以我完全考虑了这个问题，但是将原始帖子保留在下面，因为以这种方式绘制矩阵仍然很不错.我发布的函数现在带有x，y，z和几个可选参数，并吐出一些与您想要的示例类似的东西，径向轴，图例，轮廓线和所有其他东西
[[major edit]] I was finally able to add contour lines to my original attempt, but since the two sides of the original matrix that gets contorted don't actually touch, the lines don't match up between 360 and 0 degree. So I've totally rethought the problem, but leave the original post below because it was still kind of cool to plot a matrix that way. The function I'm posting now takes x,y,z and several optional arguments, and spits back something pretty darn similar to your desired examples, radial axes, legend, contour lines and all:
PolarImageInterpolate <- function(x, y, z, outer.radius = 1,
breaks, col, nlevels = 20, contours = TRUE, legend = TRUE,
axes = TRUE, circle.rads = pretty(c(0,outer.radius))){
minitics <- seq(-outer.radius, outer.radius, length.out = 1000)
# interpolate the data
Interp <- akima:::interp(x = x, y = y, z = z,
extrap = TRUE,
xo = minitics,
yo = minitics,
linear = FALSE)
Mat <- Interp[[3]]
# mark cells outside circle as NA
markNA <- matrix(minitics, ncol = 1000, nrow = 1000)
Mat[!sqrt(markNA ^ 2 + t(markNA) ^ 2) < outer.radius] <- NA
# sort out colors and breaks:
if (!missing(breaks) & !missing(col)){
if (length(breaks) - length(col) != 1){
stop("breaks must be 1 element longer than cols")
}
}
if (missing(breaks) & !missing(col)){
breaks <- seq(min(Mat,na.rm = TRUE), max(Mat, na.rm = TRUE), length = length(col) + 1)
nlevels <- length(breaks) - 1
}
if (missing(col) & !missing(breaks)){
col <- rev(heat.colors(length(breaks) - 1))
nlevels <- length(breaks) - 1
}
if (missing(breaks) & missing(col)){
breaks <- seq(min(Mat,na.rm = TRUE), max(Mat, na.rm = TRUE), length = nlevels + 1)
col <- rev(heat.colors(nlevels))
}
# if legend desired, it goes on the right and some space is needed
if (legend) {
par(mai = c(1,1,1.5,1.5))
}
# begin plot
image(x = minitics, y = minitics, t(Mat), useRaster = TRUE, asp = 1,
axes = FALSE, xlab = "", ylab = "", col = col, breaks = breaks)
# add contours if desired
if (contours){
CL <- contourLines(x = minitics, y = minitics, t(Mat), levels = breaks)
A <- lapply(CL, function(xy){
lines(xy$x, xy$y, col = gray(.2), lwd = .5)
})
}
# add radial axes if desired
if (axes){
# internals for axis markup
RMat <- function(radians){
matrix(c(cos(radians), sin(radians), -sin(radians), cos(radians)), ncol = 2)
}
circle <- function(x, y, rad = 1, nvert = 500){
rads <- seq(0,2*pi,length.out = nvert)
xcoords <- cos(rads) * rad + x
ycoords <- sin(rads) * rad + y
cbind(xcoords, ycoords)
}
# draw circles
if (missing(circle.rads)){
circle.rads <- pretty(c(0,outer.radius))
}
for (i in circle.rads){
lines(circle(0, 0, i), col = "#66666650")
}
# put on radial spoke axes:
axis.rads <- c(0, pi / 6, pi / 3, pi / 2, 2 * pi / 3, 5 * pi / 6)
r.labs <- c(90, 60, 30, 0, 330, 300)
l.labs <- c(270, 240, 210, 180, 150, 120)
for (i in 1:length(axis.rads)){
endpoints <- zapsmall(c(RMat(axis.rads[i]) %*% matrix(c(1, 0, -1, 0) * outer.radius,ncol = 2)))
segments(endpoints[1], endpoints[2], endpoints[3], endpoints[4], col = "#66666650")
endpoints <- c(RMat(axis.rads[i]) %*% matrix(c(1.1, 0, -1.1, 0) * outer.radius, ncol = 2))
lab1 <- bquote(.(r.labs[i]) * degree)
lab2 <- bquote(.(l.labs[i]) * degree)
text(endpoints[1], endpoints[2], lab1, xpd = TRUE)
text(endpoints[3], endpoints[4], lab2, xpd = TRUE)
}
axis(2, pos = -1.2 * outer.radius, at = sort(union(circle.rads,-circle.rads)), labels = NA)
text( -1.21 * outer.radius, sort(union(circle.rads, -circle.rads)),sort(union(circle.rads, -circle.rads)), xpd = TRUE, pos = 2)
}
# add legend if desired
# this could be sloppy if there are lots of breaks, and that's why it's optional.
# another option would be to use fields:::image.plot(), using only the legend.
# There's an example for how to do so in its documentation
if (legend){
ylevs <- seq(-outer.radius, outer.radius, length = nlevels + 1)
rect(1.2 * outer.radius, ylevs[1:(length(ylevs) - 1)], 1.3 * outer.radius, ylevs[2:length(ylevs)], col = col, border = NA, xpd = TRUE)
rect(1.2 * outer.radius, min(ylevs), 1.3 * outer.radius, max(ylevs), border = "#66666650", xpd = TRUE)
text(1.3 * outer.radius, ylevs,round(breaks, 1), pos = 4, xpd = TRUE)
}
}
# Example
set.seed(10)
x <- rnorm(20)
y <- rnorm(20)
z <- rnorm(20)
PolarImageInterpolate(x,y,z, breaks = seq(-2,8,by = 1))
代码可在此处获取: https://gist.github.com/2893780
[[我的原始回答如下]]
[[my original answer follows]]
我认为您的问题对自己来说是有教育意义的，因此我接受了挑战并提出了以下不完整的功能.它的工作方式与image()相似，需要一个矩阵作为其主要输入，并减去上面的轮廓线，返回与上面示例类似的内容.
[[我在注意到代码未按照我要求的顺序绘制后，于6月6日编辑了代码.固定的.目前正在研究轮廓线和图例.]]
I thought your question would be educational for myself, so I took up the challenge and came up with the following incomplete function. It works similar to image(), wants a matrix as its primary input, and spits back something similar to your example above, minus the contour lines.
[[I edited the code June 6th after noticing that it didn't plot in the order I claimed. Fixed. Currently working on contour lines and legend.]]
# arguments:
# Mat, a matrix of z values as follows:
# leftmost edge of first column = 0 degrees, rightmost edge of last column = 360 degrees
# columns are distributed in cells equally over the range 0 to 360 degrees, like a grid prior to transform
# first row is innermost circle, last row is outermost circle
# outer.radius, By default everything scaled to unit circle
# ppa: points per cell per arc. If your matrix is little, make it larger for a nice curve
# cols: color vector. default = rev(heat.colors(length(breaks)-1))
# breaks: manual breaks for colors. defaults to seq(min(Mat),max(Mat),length=nbreaks)
# nbreaks: how many color levels are desired?
# axes: should circular and radial axes be drawn? radial axes are drawn at 30 degree intervals only- this could be made more flexible.
# circle.rads: at which radii should circles be drawn? defaults to pretty(((0:ncol(Mat)) / ncol(Mat)) * outer.radius)
# TODO: add color strip legend.
PolarImagePlot <- function(Mat, outer.radius = 1, ppa = 5, cols, breaks, nbreaks = 51, axes = TRUE, circle.rads){
# the image prep
Mat <- Mat[, ncol(Mat):1]
radii <- ((0:ncol(Mat)) / ncol(Mat)) * outer.radius
# 5 points per arc will usually do
Npts <- ppa
# all the angles for which a vertex is needed
radians <- 2 * pi * (0:(nrow(Mat) * Npts)) / (nrow(Mat) * Npts) + pi / 2
# matrix where each row is the arc corresponding to a cell
rad.mat <- matrix(radians[-length(radians)], ncol = Npts, byrow = TRUE)[1:nrow(Mat), ]
rad.mat <- cbind(rad.mat, rad.mat[c(2:nrow(rad.mat), 1), 1])
# the x and y coords assuming radius of 1
y0 <- sin(rad.mat)
x0 <- cos(rad.mat)
# dimension markers
nc <- ncol(x0)
nr <- nrow(x0)
nl <- length(radii)
# make a copy for each radii, redimension in sick ways
x1 <- aperm( x0 %o% radii, c(1, 3, 2))
# the same, but coming back the other direction to close the polygon
x2 <- x1[, , nc:1]
#now stick together
x.array <- abind:::abind(x1[, 1:(nl - 1), ], x2[, 2:nl, ], matrix(NA, ncol = (nl - 1), nrow = nr), along = 3)
# final product, xcoords, is a single vector, in order,
# where all the x coordinates for a cell are arranged
# clockwise. cells are separated by NAs- allows a single call to polygon()
xcoords <- aperm(x.array, c(3, 1, 2))
dim(xcoords) <- c(NULL)
# repeat for y coordinates
y1 <- aperm( y0 %o% radii,c(1, 3, 2))
y2 <- y1[, , nc:1]
y.array <- abind:::abind(y1[, 1:(length(radii) - 1), ], y2[, 2:length(radii), ], matrix(NA, ncol = (length(radii) - 1), nrow = nr), along = 3)
ycoords <- aperm(y.array, c(3, 1, 2))
dim(ycoords) <- c(NULL)
# sort out colors and breaks:
if (!missing(breaks) & !missing(cols)){
if (length(breaks) - length(cols) != 1){
stop("breaks must be 1 element longer than cols")
}
}
if (missing(breaks) & !missing(cols)){
breaks <- seq(min(Mat,na.rm = TRUE), max(Mat, na.rm = TRUE), length = length(cols) + 1)
}
if (missing(cols) & !missing(breaks)){
cols <- rev(heat.colors(length(breaks) - 1))
}
if (missing(breaks) & missing(cols)){
breaks <- seq(min(Mat,na.rm = TRUE), max(Mat, na.rm = TRUE), length = nbreaks)
cols <- rev(heat.colors(length(breaks) - 1))
}
# get a color for each cell. Ugly, but it gets them in the right order
cell.cols <- as.character(cut(as.vector(Mat[nrow(Mat):1,ncol(Mat):1]), breaks = breaks, labels = cols))
# start empty plot
plot(NULL, type = "n", ylim = c(-1, 1) * outer.radius, xlim = c(-1, 1) * outer.radius, asp = 1, axes = FALSE, xlab = "", ylab = "")
# draw polygons with no borders:
polygon(xcoords, ycoords, col = cell.cols, border = NA)
if (axes){
# a couple internals for axis markup.
RMat <- function(radians){
matrix(c(cos(radians), sin(radians), -sin(radians), cos(radians)), ncol = 2)
}
circle <- function(x, y, rad = 1, nvert = 500){
rads <- seq(0,2*pi,length.out = nvert)
xcoords <- cos(rads) * rad + x
ycoords <- sin(rads) * rad + y
cbind(xcoords, ycoords)
}
# draw circles
if (missing(circle.rads)){
circle.rads <- pretty(radii)
}
for (i in circle.rads){
lines(circle(0, 0, i), col = "#66666650")
}
# put on radial spoke axes:
axis.rads <- c(0, pi / 6, pi / 3, pi / 2, 2 * pi / 3, 5 * pi / 6)
r.labs <- c(90, 60, 30, 0, 330, 300)
l.labs <- c(270, 240, 210, 180, 150, 120)
for (i in 1:length(axis.rads)){
endpoints <- zapsmall(c(RMat(axis.rads[i]) %*% matrix(c(1, 0, -1, 0) * outer.radius,ncol = 2)))
segments(endpoints[1], endpoints[2], endpoints[3], endpoints[4], col = "#66666650")
endpoints <- c(RMat(axis.rads[i]) %*% matrix(c(1.1, 0, -1.1, 0) * outer.radius, ncol = 2))
lab1 <- bquote(.(r.labs[i]) * degree)
lab2 <- bquote(.(l.labs[i]) * degree)
text(endpoints[1], endpoints[2], lab1, xpd = TRUE)
text(endpoints[3], endpoints[4], lab2, xpd = TRUE)
}
axis(2, pos = -1.2 * outer.radius, at = sort(union(circle.rads,-circle.rads)))
}
invisible(list(breaks = breaks, col = cols))
}
我不知道如何在极性表面上正确地进行插值，因此假设您可以实现并将数据输入矩阵，那么此函数将为您绘制图表.像image()一样绘制每个单元格，但是内部单元格很小.这是一个示例:
I don't know how to interpolate properly over a polar surface, so assuming you can achieve that and get your data into a matrix, then this function will get it plotted for you. Each cell is drawn, as with image(), but the interior ones are teeny tiny. Here's an example:
set.seed(1)
x <- runif(20, min = 0, max = 360)
y <- runif(20, min = 0, max = 40)
z <- rnorm(20)
Interp <- akima:::interp(x = x, y = y, z = z,
extrap = TRUE,
xo = seq(0, 360, length.out = 300),
yo = seq(0, 40, length.out = 100),
linear = FALSE)
Mat <- Interp[[3]]
PolarImagePlot(Mat)
无论如何，请随时进行修改并按照您的意愿进行操作.可以在Github上找到代码: https://gist.github.com/2877281
By all means, feel free to modify this and do with it what you will. Code is available on Github here: https://gist.github.com/2877281
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