Could not retrieve add offset

[Diane Stokes]

Paul,

Your descriptor file worked for me (modifying the DSET line only) on
both linux and AIX using a similar, if not the same, "Hoop-written" slp
dataset from CDC.  Additionally, Hoop's suggestion:

sdfopen
/home/pfwillis/2006/Grads/circulation/Climate/data/slp_daily.1999.nc
/home/pfwillis/2006/Grads/circulation/Climate/data/slp_daily.%y4.nc 731

worked as well and I was able to plot the full time series.

If Hoop's suggested sdfopen call does not work for you, I suggest you
send the full output from "q config" to the list.  Maybe that will
trigger a response from someone that understands build issues.  In case
it might help, here's the output from "q config" on our linux server:

Config: v1.9b4 32-bit little-endian readline sdf/xdf netcdf lats athena
printim

Grid Analysis and Display System (GrADS) Version 1.9b4
Copyright (c) 1988-2005 by Brian Doty and IGES
Center for Ocean-Land-Atmosphere Studies (COLA)
Institute for Global Environment and Society (IGES)
This program is distributed WITHOUT ANY WARRANTY
See file COPYRIGHT for more information.

Built Wed Sep  7 13:47:36 EDT 2005 for ia64-unknown-linux-gnu

This version of GrADS has been configured with the following options:

   o This is a 32-bit LITTLE ENDIAN machine version.
   o Command line editing (readline) ENABLED.
   o CIRES/CDC (http://www.cdc.noaa.gov) SDF/XDF interface ENABLED.
     Use sdfopen/xdfopen to read NetCDF files.
   o DTYPE netcdf is ENABLED; DTYPE hdfsds is DISABLED.
   o OPeNDAP (a.k.a. DODS) gridded data interface DISABLED.
   o OPeNDAP (a.k.a. DODS) station data interface DISABLED.
   o PCMDI (http://www-pcmdi.llnl.gov) LATS interface ENABLED.
     This version is configured to write GRIB and NetCDF files.
   o DAO (http://dao.gsfc.nasa.gov) Athena Widget GUI ENABLED.
   o NRL/DAO/PCMDI XA or ImageMagick Image Output DISABLED.
   o printim command for direct png/gif output ENABLED.
     (via the GD Library -- http://www.boutell.com/gd)

For additional information please consult http://grads.iges.org/grads/



Good luck.
   Diane Stokes



Willis, Paul ENV:EX wrote:
> Trying to concantenate two netCDF files:  each, a year's worth of daily
> slp means.  data can be plotted but is clearly wrong.  It appears to be an
> offsest problem.  See below.
>
> Do not understand the warning about the missing value as well.
>
> Running GrADS 1.9b4 on linux.
>
>
> Thanks in advance for any guidance.
>
> -paul
> *********************
>
>
> ga-> q dim
>
> Default file number is: 1
>
> X is varying   Lon = 0 to 360   X = 1 to 145
>
> Y is varying   Lat = -90 to 90   Y = 0.999999 to 73
>
> Z is fixed     Lev = 1  Z = 1
>
> T is fixed     Time = 00Z01JAN1999  T = 1
>
> ga-> d slp
> "  -- using -1e+15 insteade data type for "missing_value
> " not handled
> -- using -1e+15 instead
>
> Warning: Could not retrieve add offset data type -- setting add offset to
> 0.0
>
> Contouring: -20000 to -16500
>  interval 500
>
> *********************
> here is my descriptor file
> *********************
> dset /home/pfwillis/2006/Grads/circulation/Climate/data/slp_daily.%y4.nc
> dtype netcdf
> options yrev template
> undef -1e15 missing_value
> unpack scale_factor add_offset
> title NCEP Reanalysis Daily Averages
> xdef 144 linear 0 2.5
> ydef 73 linear -90 2.5
> zdef   1 linear 1 1
> tdef 731 linear 00Z01jan1999 24hr
> vars 1
> slp 0 t,y,x mean Daily Sea Level Pressure [Pa]
> endvars
>
>
> *********************
> should an ncdump provide useful information on this, see below.
> *********************
>
>
> netcdf slp_daily.1999 {
> dimensions:
>  lon = 144 ;
>  lat = 73 ;
>  time = UNLIMITED ;
>  // (365 currently)
> variables:
>  float lat(lat) ;
>   lat:units = "degrees_north" ;
>
>   lat:actual_range = 90.f, -90.f ;
>   lat:long_name = "Latitude" ;
>
>  float lon(lon) ;
>   lon:units = "degrees_east" ;
>
>   lon:long_name = "Longitude" ;
>
>   lon:actual_range = 0.f, 357.5f ;
>  double time(time) ;
>
>   time:units = "hours since 1-1-1 00:00:0.0" ;
>
>   time:long_name = "Time" ;
>   time:actual_range = 17514144., 17522880. ;
>
>   time:delta_t = "0000-00-01 00:00:00" ;
>
> time:avg_period = "0000-00-01 00:00:00" ;
>  short slp(time, lat, lon) ;
>
> slp:long_name = "mean Daily Sea Level Pressure" ;
>
>   slp:valid_range = 87000.f, 115000.f ;
>
>   slp:actual_range = 92970.f, 110552.f ;
>
>   slp:units = "Pascals" ;
>
>   slp:add_offset = 119765.f ;
>
>   slp:scale_factor = 1.f ;
>
>   slp:missing_value = 32766s ;
>
>   slp:precision = 0s ;
>
>   slp:least_significant_digit = -1s ;
>
>  slp:GRIB_id = 2s ;
>
>   slp:GRIB_name = "PRMSL" ;
>
>   slp:var_desc = "Sea Level Pressure\n",
>    "P" ;
>
>   slp:dataset = "NCEP Reanalysis Daily Averages\n",
>    "AJ" ;
>
>   slp:level_desc = "Sea Level\n",
>    "I" ;
>
>   slp:statistic = "Mean\n",
>    "M" ;
>
>   slp:parent_stat = "Individual Obs\n",
>    "I" ;
>
>
> // global attributes:
>   :Conventions = "COARDS" ;
>
>   :title = "mean daily NMC reanalysis (1999)" ;
>
>   :base_date = 1999s, 1s, 1s ;
>
>   :history = "created 99/01/04 by Hoop (netCDF2.3)" ;
>
>   :description = "Data is from NMC initialized reanalysis\n",
>
>    "(4x/day).  It consists of most variables
> interpolated to\n",
>
>    "pressure surfaces from model (sigma) surfaces." ;
>
>   :platform = "Model" ;
>
>
> data:
>
>  lat = .......
>