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ggRGB无法使用RStoolbox R包绘制蒙版图像

rstoolbox terra ggplot2 r

1

UseR10085 dieghernan · 技术社区 · 6 月前

ggRGB无法绘制蒙版图像。这是一个最小的、可重复的例子

library(terra)
library(ggplot2)
library(RStoolbox)

lsat

plotRGB(lsat,
        r = 3,
        g = 2,
        b = 1,
        stretch = 'hist')

m <- draw(x="polygon", n = 5)

lsat.masked <- crop(lsat, m, mask = T)

ggplot() + ggRGB(img = lsat.masked,
                 r = 3,
                 g = 2,
                 b = 1,
                 stretch = 'hist',
                 ggLayer = T)

它返回以下错误

网格错误。调用.graphics(C_raster、x$raster、x$x、x$y、x$width、x$height): 无法分配大小为67108864 Tb的内存块此外:警告信息: 在矩阵(z,nrow=nrow(rr),ncol=ncol(rr)和byrow=TRUE)中: 数据长度[5888]不是行数[88]的子倍数或倍数

1 回复 | 直到 6 月前

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UseR10085 dieghernan 6 月前

这是一个不完整的答案,因为我在 ggRGB ,但您可以考虑使用 tidyterra 相反,请参阅reprex:

library(terra)
#> terra 1.8.5
library(ggplot2)
library(RStoolbox)
#> This is version 1.0.0 of RStoolbox

lsat

plotRGB(lsat, r = 3, g = 2, b = 1, stretch = "hist")


# SpatVector as standalone object

m <- structure(list(geom = "POLYGON ((620947.959184 -412745.345369, 621312.951334 -414249.11303, 623254.709576 -414526.507064, 623897.095761 -413154.136578, 621152.354788 -411767.166405, 620947.959184 -412745.345369))"),
  class = "data.frame",
  row.names = c(NA, -1L)
)

# To SpatVector with the right CRS
m <- vect(m$geom)
crs(m) <- crs(lsat)


plot(m, add = TRUE, col = "red")

lsat.masked <- crop(lsat, m, mask = T)

plotRGB(lsat.masked, r = 3, g = 2, b = 1, stretch = "hist")

ggplot() +
  ggRGB(
    img = lsat.masked,
    r = 3,
    g = 2,
    b = 1,
    stretch = "hist",
    ggLayer = T
  )
#> Warning in matrix(z, nrow = nrow(rr), ncol = ncol(rr), byrow = TRUE): data
#> length [5793] is not a sub-multiple or multiple of the number of rows [92]
#> Error in grid.Call.graphics(C_raster, x$raster, x$x, x$y, x$width, x$height, : cannot allocate memory block of size 67108864 Tb

与 蒂蒂泰拉 您只需要在绘图功能之外执行拉伸,然后应用 geom_spatraster_rgb :

# Alternative with tidyterra
library(tidyterra)
#> 
#> Adjuntando el paquete: 'tidyterra'
#> The following object is masked from 'package:stats':
#> 
#>     filter

# Strecth as standalone fun, equivalent to plotRGB(..., stretch = "hist")

lsat.masked_st <- stretch(lsat.masked, histeq = TRUE, scale = 255)

ggplot() +
  geom_spatraster_rgb(data = lsat.masked_st, r = 3, g = 2, b = 1) +
  geom_spatvector(data = m, color = "red", fill = NA, linewidth = 3)

plot with tidyterra

^{创建于2025年1月5日

reprex v2.1.1}