Problems with a grid

Added by Philippe Lucas-Picher about 5 years ago

Hello,

I would like to interpolate the SPREAD spanish precipitation dataset attached to another grid using the cdo tools. Here is the ncdump of the file showing some details about the grid.
Can someone help me to convert the attributes to be able to use the cdo remapbil to interpolate the data to another grid. Thank you. Phil

netcdf SPREAD_pen_pcp {
dimensions:
Y = 174 ;
X = 207 ;
time = 23011 ;
variables:
double Y(Y) ;
Y:units = "meters" ;
Y:long_name = "Y" ;
Y:axis = "Y" ;
double X(X) ;
X:units = "meters" ;
X:long_name = "X" ;
X:axis = "X" ;
int time(time) ;
time:units = "days since 1950-01-01" ;
time:long_name = "time" ;
int pcp(time, X, Y) ;
pcp:units = "mm*10" ;
pcp:_FillValue = -9999 ;
pcp:long_name = "Precipitation" ;

// global attributes:
:title = "Daily precipitation of peninsular Spain" ;
:summary = "This is a gridded dataset of daily precipitation of peninsular Spain built from 11,513 stations to estimate precipitation in each grid point of 5 km of spatial resolution. The data include precipitation estimations from 1950-01-01 to 2012-12-31." ;
:keywords = "daily,precipitation,Iberian Peninsula,Spain,uncertainty" ;
:id = "SPREAD" ;
:naming_authority = "Spanish PREcipitation At Daily scale" ;
:history = "v1.0" ;
:date_created = "November-2016" ;
:creator_name = "Roberto Serrano-Notivoli; Martín de Luis; Santiago Beguería and Miguel Ángel Saz" ;
:maintainer_name = "Roberto Serrano-Notivoli" ;
:maintainer_email = "rs@unizar.es" ;
:institution = "University of Zaragoza and CSIC" ;
:project = "CGL2012-31668;CGL2015-69985-R;CGL2011-24185 and CGL2014-52135-C3-1-R" ;
:processing_level = "Quality-controlled. Final values." ;
:acknowledgment = "This study was supported by research projects financed by the Spanish Ministerio de Economía y Competitividad (MINECO) and FEDER-ERDF funds. We were financially supported by the Government of Aragón through the ‘Programme of research groups’ (groups ‘H38, Clima, Cambio Global y Sistemas Naturales’ and ‘E68, Geomorfología y Cambio Global’)" ;
:geospatial_lat_min = 3990766. ;
:geospatial_lat_max = 4855766. ;
:geospatial_lon_min = -14016. ;
:geospatial_lon_max = 1015984. ;
:time_coverage_start = "1950-01-01" ;
:time_coverage_end = "2012-12-31" ;
:time_coverage_duration = "P15341D" ;
:time_coverage_resolution = "Daily" ;
:geospatial_lat_units = "metres" ;
:geospatial_lat_resolution = 5000. ;
:geospatial_lon_units = "metres" ;
:geospatial_lon_resolution = 5000. ;
:long_name = "Daily precipitation" ;
:units = "mm*10" ;
:data_sources = "AEMET;SIAR-MAGRAMA;METEOCAT;SAIH Hidrosur;SAIH Jucar;SAIH Tajo;SAIH Cantábrico;SAIH Duero;SAIH Ebro;SAIH Guadalquivir;SAIH Miño-Sil;SAIH Segura" ;
:coordinate_system = "ED50 / UTM zone 30N. EPSG:23030" ;

SPREAD_pen_pcp_1timestep.nc (169 KB) SPREAD_pen_pcp_1timestep.nc

Replies (3)

RE: Problems with a grid - Added by Ralf Mueller about 5 years ago

hi!

CF-convention requires latitudes and longitudes. you use meters without any reference point. My best guess is to go back to the source of the data and ask for grid in regular coordinates based on degrees.

Without any reference point I don't see a way for doing the coordinate transformation yourself

cheers
ralf

RE: Problems with a grid - Added by Philippe Lucas-Picher about 5 years ago

Hi Ralf,

thanks for your reply. However, there is a reference lat and lon at the bottom of the ncdump.

:geospatial_lat_min = 3990766. ;
:geospatial_lat_max = 4855766. ;
:geospatial_lon_min = -14016. ;
:geospatial_lon_max = 1015984. ;

Is that sufficient to determine the attributes ?

Phil

RE: Problems with a grid - Added by Ralf Mueller about 5 years ago

IMO these are meters and hence no absolute point on mother earth

   File format : NetCDF4
    -1 : Institut Source   T Steptype Levels Num    Points Num Dtype : Parameter name
     1 : unknown  unknown  v instant       1   1     36018   1  I32  : pcp           
   Grid coordinates :
     1 : generic                  : points=36018 (207x174)
                                X : -14016 to 1015984 by 5000 meters
                                Y : 3990766 to 4855766 by 5000 meters
   Vertical coordinates :
     1 : surface                  : levels=1
   Time coordinate :  1 step
     RefTime =  1950-01-01 00:00:00  Units = days  Calendar = standard
  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss
  1950-01-02 00:00:00

This is not about attribute AFAIK - there must be read coordinate values in degrees to make it usable for CDO.

(1-3/3)

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