Hi Peng,
This is a "curvilinear" grid, so you can use one of the functions for curvilinear data:
yes? show functions *curv*
It sounds as if SAMPLEXY_CURV_NRST is probably the one you want.
Ansley
On 9/15/2014 12:37 PM, Ge Peng - NOAA Affiliate wrote:
Hi,
I have several datasets with different, non-standard polar-stereographic projections. Info from one data set is provided below.
I would like to get help in linking lon and lat with variable dimensions to extract values along a ship-track (time, lat, lon) which is irregular in time and space.
Suggestions on extracting methods are also appreciated - samplexyt is using linear interpolation and I would like to use value from the nearest data point instead.
Please let me know if you need any additional information.
Thanks,
--- Peng
The ferret show data command for one data set shows the following:
currently SET data sets:1> ./APPx_n025_Tsurf_Cld_daily_1400.nc (default)name title I J K LLA Latitude 1:361 1:361 ... ...LO Longitude 1:361 1:361 ... ...T_SURF daily APPx Surface Temperature 1:361 1:361 ... 1:365
Both lo and la are 2-dimension arrays and are not the same for all i and j indices.
And ncdump -h gives the following:
netcdf APPx_n025_Tsurf_Cld_daily_1400 {dimensions:COLUMNS = 361 ;bnds = 2 ;ROWS = 361 ;TIME = UNLIMITED ; // (365 currently)variables:double COLUMNS(COLUMNS) ;COLUMNS:point_spacing = "even" ;COLUMNS:axis = "X" ;COLUMNS:bounds = "COLUMNS_bnds" ;double COLUMNS_bnds(COLUMNS, bnds) ;double ROWS(ROWS) ;ROWS:point_spacing = "even" ;ROWS:axis = "Y" ;ROWS:bounds = "ROWS_bnds" ;double ROWS_bnds(ROWS, bnds) ;float LA(ROWS, COLUMNS) ;LA:missing_value = -1.e+34f ;LA:_FillValue = -1.e+34f ;LA:long_name = "Latitude" ;LA:units = "degrees_north" ;float LO(ROWS, COLUMNS) ;LO:missing_value = -1.e+34f ;LO:_FillValue = -1.e+34f ;LO:long_name = "Longitude" ;LO:units = "degrees_east" ;double TIME(TIME) ;TIME:units = "day since 1997-01-01 14:00:00" ;TIME:time_origin = "01-JAN-1997 14:00:00" ;TIME:axis = "T" ;TIME:bounds = "TIME_bnds" ;double TIME_bnds(TIME, bnds) ;float T_SURF(TIME, ROWS, COLUMNS) ;T_SURF:missing_value = 999.9f ;T_SURF:_FillValue = 999.9f ;T_SURF:long_name = "daily APPx Surface Temperature (K)" ;T_SURF:history = "From APPx_n025_All_daily_1400" ;
--
Ge Peng, Ph.D
Research Scholar
Cooperative Institute for Climate and Satellites NC
North Carolina State University
NOAA's National Climatic Data Center
151 Patton Ave, Asheville, NC 28801
ge.peng@xxxxxxxx
o: +1 828 257 3009
f: +1 828 257 3002
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