I am trying to read the below netcdf using terra package. The netcdf file contains data for 3 years. When I load the data, it gives me below warning which I never had before.
gdp <- terra::rast(file.path(dir_ls$base, 'v3.nc'))
Warning message:
In new_CppObject_xp(fields$.module, fields$.pointer, ...) :
GDAL Message 1: No UNIDATA NC_GLOBAL:Conventions attribute
If I check the projection, it shows me NA
crs(gdp)
Even I try to project the data, the projection is still NA
gdp <- terra::project(gdp, "epsg:4326")
crs(gdp)
NA
EDIT
terra::gdal(lib="")
gdal proj geos
"2.2.3" "4.9.3" "3.7.1
The gdp file looks like
class : SpatRaster
dimensions : 21600, 43200, 3 (nrow, ncol, nlyr)
resolution : 0.008333333, 0.008333333 (x, y)
extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax)
coord. ref. : lon/lat WGS 84 (EPSG:4326)
source : GDP_PPP_30arcsec_v3.nc
varname : GDP_PPP (Gross Domestic Production (GDP) (PPP))
names : GDP_PPP_1, GDP_PPP_2, GDP_PPP_3
unit : constant 2011 international US dollar, constant 2011
international US dollar, constant 2011 international US dollar
My session info is here:
R version 4.0.5 (2021-03-31)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 18.04.5 LTS
Matrix products: default
BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.7.1
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.7.1
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C LC_TIME=en_US.UTF-8
[4] LC_COLLATE=en_US.UTF-8 LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=en_US.UTF-8 LC_NAME=C LC_ADDRESS=C
[10] LC_TELEPHONE=C LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] rgdal_1.5-32 rgeos_0.5-9 raster_3.4-10 sp_1.4-5 geodata_0.4-9
[6] sf_0.9-8 terra_1.6-7 forcats_0.5.1 stringr_1.4.0 dplyr_1.0.6
[11] purrr_0.3.4 readr_1.4.0 tidyr_1.1.3 tibble_3.1.1 ggplot2_3.3.3
[16] tidyverse_1.3.1 data.table_1.14.0
loaded via a namespace (and not attached):
[1] tinytex_0.31 tidyselect_1.1.1 xfun_0.22 lattice_0.20-44
[5] haven_2.4.1 colorspace_2.0-1 vctrs_0.3.8 generics_0.1.0
[9] utf8_1.2.1 rlang_0.4.11 e1071_1.7-6 pillar_1.6.0
[13] glue_1.4.2 withr_2.4.2 DBI_1.1.1 dbplyr_2.1.1
[17] modelr_0.1.8 readxl_1.3.1 lifecycle_1.0.0 munsell_0.5.0
[21] gtable_0.3.0 cellranger_1.1.0 rvest_1.0.0 codetools_0.2-18
[25] class_7.3-19 fansi_0.4.2 broom_0.7.6 Rcpp_1.0.6
[29] KernSmooth_2.23-20 scales_1.1.1 backports_1.2.1 classInt_0.4-3
[33] jsonlite_1.7.2 fs_1.5.0 hms_1.0.0 stringi_1.6.1
[37] grid_4.0.5 cli_2.5.0 tools_4.0.5 magrittr_2.0.1
[41] proxy_0.4-25 crayon_1.4.1 pkgconfig_2.0.3 ellipsis_0.3.2
[45] xml2_1.3.2 reprex_2.0.0 lubridate_1.7.10 assertthat_0.2.1
[49] httr_1.4.2 rstudioapi_0.13 R6_2.5.0 units_0.7-1
[53] compiler_4.0.5
As you show, gdp clearly has a defined coordinate reference system:
coord. ref. : lon/lat WGS 84 (EPSG:4326)
and projecting it to that same crs again makes no sense.
I do not think that terra would ever report a crs as NA. Since you are not showing your actual code and results, it is hard to say what goes wrong. But one red flag is that you have many packages loaded. If you start with a clean session (without any packages loaded) you should be able to do
library(terra)
r <- rast("filename")
crs(r)
And get a better result. Perhaps you load another package that hides the terra::crs method? In that case, you could do
terra::crs(r)
Like this:
library(terra)
r <- rast("GDP_per_capita_PPP_1990_2015_v2.nc")
r
#class : SpatRaster
#dimensions : 2160, 4320, 26 (nrow, ncol, nlyr)
#resolution : 0.08333333, 0.08333334 (x, y)
#extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax)
#coord. ref. : lon/lat WGS 84
#source : GDP_per_capita_PPP_1990_2015_v2.nc
#varname : GDP_per_capita_PPP (Gross Domestic Production (GDP) per capita (PPP))
#names : GDP_p~PPP_1, GDP_p~PPP_2, GDP_p~PPP_3, GDP_p~PPP_4, GDP_p~PPP_5, GDP_p~PPP_6, ...
#unit : constant 2011 international US dollar, constant 2011 international US dollar, constant 2011 international US dollar, constant 2011 international US dollar, constant 2011 international US dollar, constant 2011 international US dollar, ...
crs(r, proj=T)
#[1] "+proj=longlat +datum=WGS84 +no_defs"
None of this has to do with the warning you are getting (I think you can ignore that warning).