[英]Aligning large raster and SpatialPoints in R
我有兩個數據集:
該文件被描述為具有 EPSG:3577 https://epsg.io/3577的投影。 所有其他元數據以及數據本身都可以在http://www.agriculture.gov.au/abares/forestsaustralia/forest-data-maps-and-tools/spatial-data/forest-cover中找到
由於這也是一個大型數據集,我將只提供這個的頭部:
firms <- structure(list(latitude = c(-20.5897, -22.4119, -21.132, -23.9083,
-23.5908, -23.689), longitude = c(147.6421, 148.8484, 148.1897,
147.2966, 150.1676, 150.0994), brightness = c(320.7, 316.7, 320.5,
320.1, 315.8, 314.3), scan = c(1.6, 2.1, 1.8, 1.7, 2.7, 2.7),
track = c(1.3, 1.4, 1.3, 1.3, 1.6, 1.6), acq_date = c("2017-01-01",
"2017-01-01", "2017-01-01", "2017-01-01", "2017-01-01", "2017-01-01"
), acq_time = c(47L, 47L, 47L, 47L, 47L, 47L), satellite = c("Terra",
"Terra", "Terra", "Terra", "Terra", "Terra"), instrument = c("MODIS",
"MODIS", "MODIS", "MODIS", "MODIS", "MODIS"), confidence = c(34L,
26L, 36L, 53L, 33L, 22L), version = c(6.2, 6.2, 6.2, 6.2,
6.2, 6.2), bright_t31 = c(299.6, 295.3, 299.7, 296.6, 291.7,
289.3), frp = c(19, 25.8, 22.9, 17.6, 35.4, 30), daynight = c("D",
"D", "D", "D", "D", "D"), type = c(0L, 0L, 0L, 0L, 0L, 0L
)), row.names = c(NA, -6L), class = c("data.table", "data.frame"
), .internal.selfref = <pointer: 0x10200e2e0>)
我的目標很簡單:
Plot 柵格數據,然后 plot 將 csv 文件中的每一行作為柵格頂部的一個點。
我對plot()
、 levelplot()
或ggplot()
很滿意,盡管后者看起來很傻,因為將這個巨大的柵格轉換為 data.frame 需要花費太多時間。
到目前為止,我的代碼如下所示:
library(rgdal)
library(raster)
library(rasterVis)
library(sp)
test <- raster('w001000.adf')
coordinates(firms) <- ~longitude + latitude
firms_pts <- SpatialPoints(coords=coordinates(firms), proj4string = CRS("+proj=aea +lat_1=-18 +lat_2=-36 +lat_0=0 +lon_0=132 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"))
crs
firms_lyr <- spTransform(firms_pts, crs(test))
當我嘗試 plot 此時的數據時,我看不到任何點。
extent(test) <- extent(firms)
plot(test)
points(firms_lyr, pch=16, cex=0.1)
顯然,這與投影有關。
我很確定我在步驟 3 和/或 4 中做錯了什么
這管用嗎? 我不確定這些點是否是遠東的點。
firms <- structure(list(latitude = c(-20.5897, -22.4119, -21.132, -23.9083, -23.5908, -23.689),
longitude = c(147.6421, 148.8484, 148.1897, 147.2966, 150.1676, 150.0994)),
.Names = c("longitude", "latitude"),
class = "data.frame", row.names = c(NA, -6L))
xy <- firms[,c(2,1)]
firms_pts <- SpatialPointsDataFrame(coords = xy, data = firms,
proj4string = CRS("+proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0"))
library(raster)
setwd(paste(dirname(rstudioapi::getActiveDocumentContext()$path), "/aus_for18", sep=""))
test <- raster("aus_for18.adf")
firms_lyr <- spTransform(firms_pts, crs(test))
plot(test)
points(firms_lyr, pch=16, cex=1) #Queensland points
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