R可以画图吗？

我想知道 R 中是否有任何包可以使用 x、y 坐标和形状大小来绘制如下内容：

我有车辆前中心的坐标及其尺寸（长度和宽度）。

Edit

原始数据集如下所示：

> head(df)
  Vehicle.ID Frame.ID Global.X Global.Y Vehicle.Length Vehicle.width Lane Preceding.Vehicle.ID Following.Vehicle.ID Spacing Headway
1          2       43  6451214  1873261           14.5           4.9    2                    0                   13       0       0
2          2       44  6451217  1873258           14.5           4.9    2                    0                   13       0       0
3          2       45  6451220  1873256           14.5           4.9    2                    0                   13       0       0
4          2       46  6451223  1873253           14.5           4.9    2                    0                   13       0       0
5          2       47  6451225  1873250           14.5           4.9    2                    0                   13       0       0
6          2       48  6451228  1873247           14.5           4.9    2                    0                   13       0       0

对于任何给定的帧，我想可视化间隙，例如，对于帧号。 500：

ff <- subset(df, Frame.ID==500)
qplot(x=Global.X, y=Global.Y, data=ff)

所有这些点都是车辆的前中心坐标。我不知道如何显示每辆车的长度和宽度并标记间隙值。

所以，我不提倡你依赖ggplot这样做，因为很可能其他一些建议的解决方案更好，但是这个问题引起了我的兴趣，因为我一直想深入研究ggplot一阵子。这就是我设法想出的：

ggplot(df, aes(x=x, y=y, length=length, width=width, fill=label)) +
  geom_hline(yintercept=seq(5, 35, by=10), color="white", size=2, linetype=2) +
  geom_car() +
  coord_equal() +
  theme(panel.background = element_rect(fill="#555555"), 
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank())

您还可以添加箭头geom_segment或明确的标签geom_text，但我们将其作为练习留给读者。

现在，为了让它发挥作用，我们必须创建geom_car，不过如果你不需要详细的图片，你可以使用geom_rect。这是geom_car（注：现在也可以作为ggbg包 https://github.com/brodieG/ggbg):

# Generate a car 'grob' using a baseline PNG

car.raster <- png::readPNG("~/Downloads/car2.png")

# The `grid` grob actually responsible for rendering our car, 
# combines our transparent car elements with a background rectangle
# for color/fill.

carGrob <- function(x, y, length, width, gp) {
  grid::grobTree(
    grid::rectGrob(
      x, y, hjust=.5, height=width, width=length,
      gp = gp
    ),
    grid::rasterGrob(
      car.raster, x=x, y=y, hjust=.5, height=width, width=length
) ) }
# The `ggproto` object that maps our data to the `grid` grobs

GeomCar <- ggplot2::ggproto("GeomCar", ggplot2::Geom,
  # Generate grobs from the data, we have to reconvert length/width so
  # that the transformations persist

  draw_panel=function(self, data, panel_params, coords) {
    with(
      coords$transform(data, panel_params),
      carGrob(
        x, y, length=xmax-xmin, width=ymax-ymin,
        gp=grid::gpar(
          col = colour, fill = alpha(fill, alpha),
          lwd = size * .pt, lty = linetype, lineend = "butt"
  ) ) ) },
  # Convert data to coordinates that will get transformed (length/width don't
  # normally).

  setup_data=function(self, data, params) {
    transform(data,
      xmin = x - length / 2, xmax = x + length / 2,
      ymin = y - width / 2, ymax = y + width / 2
  ) },
  # Required and default aesthetics

  required_aes=c("x", "y", "length", "width"),
  default_aes = aes(
    colour = NA, fill = "grey35", size = 0.5, linetype = 1, alpha = NA
  ),
  # Use the car grob in the legend

  draw_key = function(data, params, size) {
    with(
      data,
      carGrob(
        0.5, 0.5, length=.75, width=.5,
        gp = grid::gpar(
          col = colour, fill = alpha(fill, alpha),
          lwd = size * .pt, lty = linetype, lineend = "butt"
  ) ) ) }
)
# External interface

geom_car <- function(
  mapping=NULL, data=NULL, ..., inherit.aes=TRUE, show.legend=NA
) {
  layer(
    data=data, mapping=mapping, geom=GeomCar, position="identity",
    stat="identity", show.legend = show.legend, inherit.aes = inherit.aes,
    params=list(...)
  )
}

The car:

数据：

df <- read.table(h=T, t="vehicle  x y   length  width   label
1   150 10  14  5   other
2   180 8   12  5   other
3   220 10  18  5   other
4   145 20  15  5   target
5   250 18  14  5   other
6   160 30  13  5   autonomous
7   200 33  15  5   other
8   240 31  22  5   other
")