如何使用R语言terra包为栅格赋予正确的投影与范围？

尝试用R的terra包读取TIFF文件时，出现如下问题：

hh <- rast("imagery_HH.tif")
#> Warning message:
#> [rast] unknown extent 
hh
#> class       : SpatRaster 
#> dimensions  : 8371, 8946, 1  (nrow, ncol, nlyr)
#> resolution  : 1, 1  (x, y)
#> extent      : 0, 8946, 0, 8371  (xmin, xmax, ymin, ymax)
#> coord. ref. :  
#> source      : imagery_HH.tif 
#> name        : imagery_HH 

使用terra::describe()查看文件信息，发现包含EPSG:4326的CRS定义与GCP（地面控制点）相关内容：

# terra::describe("imagery_HH.tif")输出片段
   [4] "Size is 8946, 8371"                                                       
   [5] "GCP Projection = "                                                        
   [6] "GEOGCRS[\"WGS 84\","                                                      
   [7] "    DATUM[\"World Geodetic System 1984\","                                
   [8] "        ELLIPSOID[\"WGS 84\",6378137,298.257223563,"                      
   [9] "            LENGTHUNIT[\"metre\",1]]],"                                   
  [10] "    PRIMEM[\"Greenwich\",0,"                                              
  [11] "        ANGLEUNIT[\"degree\",0.0174532925199433]],"                       
  [12] "    CS[ellipsoidal,2],"                                                   
  [13] "        AXIS[\"geodetic latitude (Lat)\",north,"                          
  [14] "            ORDER[1],"                                                    
  [15] "            ANGLEUNIT[\"degree\",0.0174532925199433]],"                   
  [16] "        AXIS[\"geodetic longitude (Lon)\",east,"                          
  [17] "            ORDER[2],"                                                    
  [18] "            ANGLEUNIT[\"degree\",0.0174532925199433]],"                   
  [19] "    USAGE["                                                               
  [20] "        SCOPE[\"Horizontal component of 3D system.\"]],"                   
  [21] "        AREA[\"World.\"]],"                                                
  [22] "        BBOX[-90,-180,90,180]],"                                          
  [23] "    ID[\"EPSG\",4326]]"                                                   
  [24] "Data axis to CRS axis mapping: 2,1" 

QGIS可正常识别该文件的EPSG:4326坐标系，但terra读取后缺失CRS、分辨率与范围均不正确，如何解决？

该问题的核心是：你的TIFF文件未使用常规**地理变换（GeoTransform）参数定义坐标，而是通过地面控制点（GCP）**关联像素与地理坐标。rast()默认不会自动应用GCP，需手动处理：

方法1：使用rectify()纠正栅格 #

# 读取原始栅格
hh_raw <- rast("imagery_HH.tif")
# 获取文件中的GCP信息
gcp_data <- gcp("imagery_HH.tif")
# 为栅格指定目标CRS（从describe结果可知是EPSG:4326）
crs(hh_raw) <- "EPSG:4326"
# 将GCP绑定到栅格
hh_raw <- setGCP(hh_raw, gcp_data)
# 基于GCP纠正栅格，生成带正确地理信息的新栅格
hh_corrected <- rectify(hh_raw, crs = "EPSG:4326")

# 查看纠正后的结果
hh_corrected

方法2：使用project()直接投影 #

hh <- rast("imagery_HH.tif")
# 获取GCP数据
gcp_df <- gcp("imagery_HH.tif")
# 基于GCP将栅格投影到目标CRS
hh_proj <- project(hh, "EPSG:4326", GCP = gcp_df)

执行上述任一方法后，栅格将具备正确的EPSG:4326坐标系、对应分辨率与真实地理范围。

内容的提问来源于stack exchange，提问作者UseR10085