我有從日常氣候數據創建的柵格堆棧。可以在這裏找到:當應用於柵格堆棧時,柵格計算僅返回一個圖層
#!/bin/bash
wget -nc -c -nd http://northwestknowledge.net/metdata/data/tmmx_1982.nc
目標是從這些日常記錄中獲得每月95%的溫度值。每當我使用raster
包中的calc
時,它只返回一層而不是12(例如,12個月)我錯過了什麼?
library(raster)
library(tidyverse)
library(lubridate)
file = "../data/raw/climate/tmmx_1982.nc "
rstr <- raster(file)
> rstr class : RasterBrick dimensions : 585, 1386, 810810, 366 (nrow, ncol, ncell, nlayers) resolution : 0.04166667, 0.04166667 (x, y) extent : -124.793, -67.043, 25.04186, 49.41686 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0 data source : in memory names : layer.1, layer.2, layer.3, layer.4, layer.5, layer.6, layer.7, layer.8, layer.9, layer.10, layer.11, layer.12, layer.13, layer.14, layer.15, ... min values : 1.3268673, 0.7221603, 1.8519223, 1.6214808, 0.8629752, 1.1126643, 1.8769895, 0.9587604, 1.7360761, 2.1099827, 2.1147265, 1.8696048, 1.7619936, 2.0253942, 2.6840794, ... max values : 73.20462, 60.35675, 64.68890, 53.11994, 60.15675, 55.91125, 77.29095, 64.39179, 48.26004, 64.70559, 79.85970, 62.31242, 53.89768, 52.15949, 80.23198, ...
date_seq <- date_seq[1:nlayers(rstr)]
month_seq <- month(date_seq)
mean_tmp <- stackApply(rstr, month_seq, fun = mean)
> mean_tmp class : RasterBrick dimensions : 585, 1386, 810810, 12 (nrow, ncol, ncell, nlayers) resolution : 0.04166667, 0.04166667 (x, y) extent : -124.793, -67.043, 25.04186, 49.41686 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0 data source : /tmp/RtmpYf4pQe/raster/r_tmp_2017-09-25_182536_48012_88372.grd names : index_1, index_2, index_3, index_4, index_5, index_6, index_7, index_8, index_9, index_10, index_11, index_12 min values : 4.586111, 5.656802, 6.444234, 6.875973, 6.281896, 4.495534, 5.081545, 4.396824, 4.316368, 6.413400, 4.233641, 3.119827 max values : 49.12178, 47.61632, 44.70796, 47.57829, 46.97714, 51.61986, 37.77228, 51.30043, 42.51572, 36.86453, 37.96615, 52.15552
mean_90thtmp <- calc(mean_tmp, forceapply = TRUE,
fun = function(x) {quantile(x, probs = 0.90, na.rm = TRUE) })
> mean_90thtmp class : RasterLayer dimensions : 585, 1386, 810810 (nrow, ncol, ncell) resolution : 0.04166667, 0.04166667 (x, y) extent : -124.793, -67.043, 25.04186, 49.41686 (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0 data source : in memory names : layer values : 8.84197, 50.52144 (min, max)
建議都非常感謝!
謝謝!
由於您正在計算每月平均值的第90百分位數,因此您將獲得單個圖層。我不太確定你爲什麼計算平均值。我認爲你需要在stackApply函數中運行分位數函數,或者在一個循環中運行分位數函數,在這個循環中你從堆棧中爲每個月的每日值進行分類。當我嘗試使用stackApply方法時出現錯誤,但我會嘗試更多的想法並提交答案。 –
理想情況下,這將是每天的手段,但由於我無法創建第95百分位的每月圖像,我想我會先找出解決方案。我試着在stackApply裏面的每日圖像上運行這個函數,但是一直返回一個錯誤。我真的被卡住了,任何建議都會非常有幫助。謝謝! –