使用 BFAST 显示断点答案

【问题标题】：Using BFAST to show breakpoints使用 BFAST 显示断点
【发布时间】：2021-10-23 17:13:27
【问题描述】：

我目前正在使用 bfastSpatial，我正在尝试将断点值绘制为基于年份颜色的图例。我知道 changeMonth 函数用于绘制基于月的断点 (http://www.loicdutrieux.net/bfastSpatial/) 但是，我正试图实现与 Morrison 等人类似的结果。 (2019)https://www.mdpi.com/2072-4292/10/7/1075 任何援助将不胜感激。

【问题讨论】：

标签： r time-series raster trend r-modis

【解决方案1】：

如果要将断点日期四舍五入为整数年，可以使用floor，因为日期是十进制年。接下来，要制作与您展示的类似的图，您可以使用 tmap 包。由于您没有将任何数据附加到 OP，因此我使用了 bfastSpatial 包中包含的 tura 数据。

library(bfastSpatial)
library(tmap)

# Load tura data
data(tura)
# Perform bfast analysis
bfm <- bfmSpatial(tura, start=c(2009, 1), order=1)

# Extract the first band (breakpoints)
change <- bfm[[1]]

# As breakpoints dates are in year decimals,
# you can use floor to round them to lowest integer
change <- floor(change)

# Set shape as change, the object to plot
tm_shape(change) +
  # Plot it as raster and set the palette, number of categories,
  # style (categorical) and title of the legend.
  tm_raster(palette = "Spectral",
            n = 5,
            style = "cat",
            title = "Year") +
  # Set the legend's position and eliminate the comma used by default for
  # separating thousands values. Add background color and transparency
  tm_layout(legend.position = c("right", "bottom"),
            legend.format=list(fun=function(x) formatC(x, digits=0, format="d")),
            legend.bg.color = "white",
            legend.bg.alpha = 0.7) +
  # Add scale bar, set position and other arguments
  tm_scale_bar(breaks = c(0,0.5,1),
               position = c("right", "top"),
               bg.color = "white",
               bg.alpha = 0.7) +
  # Add north arrow with additional parameters
  tm_compass(type = "arrow", 
             position = c("left", "top"),
             bg.color = "white",
             bg.alpha = 0.7)

得到的情节：

【讨论】：