将栅格堆栈范围从米转换为 lat/lon 坐标

Question

我有一个格式如下的栅格堆栈，我 . This works but the latitude and longitude variables are in 'meters' which is the extent of the raster file, and I need them to be in decimal degrees. The R Grid file is here 格式如下：

class       : RasterBrick 
dimensions  : 205, 170, 34850, 12  (nrow, ncol, ncell, nlayers)
resolution  : 1, 1  (x, y)
extent      : 160.5, 330.5, 145.5, 350.5  (xmin, xmax, ymin, ymax)
coord. ref. : NA 
data source : \TavgM_1981.grd 
names       :   Jan.1981,   Feb.1981,   Mar.1981,   Apr.1981,   May.1981,   Jun.1981,   Jul.1981,   Aug.1981,   Sep.1981,   Oct.1981,   Nov.1981,   Dec.1981 
min values  :  1.9912137,  0.8120775,  4.0446638,  4.4135274,  6.5349769,  8.6149150,  9.9991916, 11.8400562,  9.6407796,  3.5005649,  4.1205872, -0.6106244 
max values  :   9.850221,   9.121176,  10.238524,   9.858942,  11.669445,  14.260988,  15.722292,  17.235090,  15.708690,  11.598482,  11.552235,   8.981533 
time        : Jan 1981, Feb 1981, Mar 1981, Apr 1981, May 1981, Jun 1981, Jul 1981, Aug 1981, Sep 1981, Oct 1981, Nov 1981, Dec 1981

理想情况下，我想将其转换为具有以下格式以供模型读取的 NetCDF 文件：

Dimensions:    (lat: 408, lon: 881, nb2: 2, time: 660)
Coordinates:
  * lon        (lon) float64 -44.81 -44.69 -44.56 -44.44 -44.31 -44.19 ...
  * lat        (lat) float64 21.81 21.94 22.06 22.19 22.31 22.44 22.56 22.69 ...
  * time       (time) datetime64[ns] 1951-01-16T12:00:00 1951-02-16T12:00:00 ...
Dimensions without coordinates: nb2
Data variables:
    time_bnds  (time, nb2) datetime64[ns] 1951-01-16T12:00:00 ...
    tas        (time, lat, lon) float64 nan nan nan nan nan nan nan nan nan ...

我尝试使用此方法将 Raster Brick 范围转换为 lat/lon：

sputm <- SpatialPoints(test@extent@xmin, proj4string=CRS("+proj=utm +zone=29N +datum=WGS84"))

但这给出了这个错误：

Error in (function (classes, fdef, mtable)  : unable to find an inherited method for function ‘coordinates’ for signature ‘"numeric"’

编辑：也尝试过

crs(test) <- '+proj=merc +datum=WGS84'
x <- projectRaster(test, crs='+proj=longlat +datum=WGS84') 

writeRaster(x, "rstack2.nc", overwrite=TRUE, format="CDF",     varname="Temperature", varunit="degC", 
        longname="Temperature -- raster stack to netCDF", xname="Longitude",   yname="Latitude", zname="Time (Month)")

但是当我在 panoply 中检查它时，纬度和经度坐标都是 0.0。

我不确定从这里到哪里去。

Answer 1

就我对爱尔兰的认识而言，我查看了爱尔兰的预测。我认为这是 TM75 / Irish Grid。我修改了你的光栅分辨率，使其为 2500m。

library(raster)

r <- stack("~/Bureau/TavgM_1981")
xmax(r) <- xmin(r) + 2500 * ncol(r)
ymax(r) <- ymin(r) + 2500 * nrow(r)

crs(r) <- "+proj=tmerc +lat_0=53.5 +lon_0=-8 +k=1.000035 +x_0=200000 +y_0=250000 +ellps=mod_airy +towgs84=482.5,-130.6,564.6,-1.042,-0.214,-0.631,8.15 +units=m +no_defs"

# Convert to degrees
x_wgs84 <- projectRaster(r, crs='+proj=longlat +datum=WGS84') 

writeRaster(x, "~/Bureau/TavgM_wgs84.tif", overwrite = TRUE)

您将在下方看到此分辨率+投影修改后与目标相比的结果。
我们离现实并不远，但您的原始光栅中有一些不好的地方。如果这是（不幸的）通常在有人给你一层时没有 crs，那么错过正确的分辨率是不常见的。
由于您提供的栅格被保存为“.gri/.grd”文件，这意味着它是用 R 生成的。您应该尝试获取生成文件的原始 R 代码，而不是最终修改的图层。

将栅格堆栈范围从米转换为 lat/lon 坐标

Converting raster stack extent from meters to lat/lon coordinates

r

raster

netcdf

r-raster

ncdf4