Hi Gail,
> Good morning. I'm working on an application to write out a compound data
> type to netCDF4. My compound type is of the following form.
>
> typedef struct
> {
> ushort county_id; /* county FIPS code */
> ushort year; /* year represented by planted/harvested
> acres
> and yield values */
> ubyte prac_code; /* harvest practice code */
> ushort planted_acres[NCROPS]; /* acres planted - per crop (not
> represented
> for hay/alfalfa) */
> ushort harvested_acres[NCROPS]; /* acres harvested - per crop */
> float yield[NCROPS]; /* yield - per crop */
> float percent_comp[NCROPS]; /* percent of composition */
> } crop_harvesting_acreage;
>
> netcdf crop_attributes_1970_2009 {
> types:
> compound CROP_HARVESTING_ACREAGE {
> ushort county_id ;
> ushort year ;
> ubyte prac_code ;
> ushort planted_acres(29) ;
> ushort harvested_acres(29) ;
> float yield(29) ;
> float percent_comp(29) ;
> }; // CROP_HARVESTING_ACREAGE
> dimensions:
> npractices = 7 ;
> ncounty_ids = UNLIMITED ; // (10 currently)
> nyears = 40 ;
> ncrops = 29 ;
> variables:
> CROP_HARVESTING_ACREAGE crop_harvest(ncounty_ids, nyears,
> npractices) ;
> crop_harvest:long_name = "crop harvest attributes by
> county ID, year and practice" ;
>
> The variable I'm trying to create has the following dimensions: unlimited,
> 40, 7. I'm writing this data out using nc_put_vara. It appears the
> output netCDF file has picked up my structure correctly, but I keep
> getting erroneous data in the output file. If I print the data out before
> I call nc_put_vara, the data is valid. I've even just tried to write out
> the data will all zeros, but each time there are a few fields that end up
> with incorrect values in the output file. I'm trying to write out a
> variable number of values for the unlimited dimension, but always 40 and 7
> values for the other two dimensions. I'm obviously doing something wrong
> due to the erroneous values in the output netCDF file. And, when I do
> have valid values, they are shifted down two fields in the output file
> .... after the first record is correct.
>
> Would you happen to have an example of working with compound types and
> writing out variable numbers of values? All the examples I've seen have
> written the entire structure out at once.
The attached program ca2.c shows how this can be done for a smaller
ca.cdl file based on your example.
The ncgen utility helped generate this example, but the process of
generating it also uncovered a couple of ncgen bugs, so thanks for the
example!
--Russ
Russ Rew UCAR Unidata Program
address@hidden http://www.unidata.ucar.edu
Ticket Details
===================
Ticket ID: PCB-933705
Department: Support netCDF
Priority: Normal
Status: Closednetcdf ca2 {
types:
compound CROP_HARVESTING_ACREAGE {
ushort county_id ;
ushort year ;
ubyte prac_code ;
ushort planted_acres(3) ;
ushort harvested_acres(3) ;
float yield(3) ;
float percent_comp(3) ;
}; // CROP_HARVESTING_ACREAGE
dimensions:
npractices = 1 ;
ncounty_ids = UNLIMITED ; // (2 currently)
nyears = 2 ;
variables:
CROP_HARVESTING_ACREAGE crop_harvest(ncounty_ids, nyears, npractices) ;
crop_harvest:long_name = "crop harvest attributes by\ncounty
ID, year and practice" ;
data:
crop_harvest =
{111, 2011, 13, {11, 12, 13}, {101, 102, 103}, {11.5, 12.5, 13.5}, {0.11,
0.12, 0.13}},
{222, 2011, 23, {21, 22, 23}, {201, 202, 203}, {21.5, 22.5, 23.5}, {0.21,
0.22, 0.23}},
{333, 2011, 33, {31, 32, 33}, {301, 302, 303}, {31.5, 32.5, 33.5}, {0.31,
0.32, 0.33}},
{444, 2011, 43, {41, 42, 43}, {401, 402, 403}, {41.5, 42.5, 43.5}, {0.41,
0.42, 0.43}} ;
}
#include <stdio.h>
#include <stdlib.h>
#include <netcdf.h>
typedef struct CROP_HARVESTING_ACREAGE {
unsigned short county_id;
unsigned short year;
unsigned char prac_code;
unsigned short planted_acres[3];
unsigned short harvested_acres[3];
float yield[3];
float percent_comp[3];
} CROP_HARVESTING_ACREAGE;
void
check_err(const int stat, const int line, const char *file) {
if (stat != NC_NOERR) {
(void)fprintf(stderr,"line %d of %s: %s\n", line, file,
nc_strerror(stat));
fflush(stderr);
exit(1);
}
}
int
main() {/* create ca2.nc */
int stat; /* return status */
int ncid; /* netCDF id */
/* group ids */
int root_grp;
/* type ids */
int CROP_HARVESTING_ACREAGE_typ;
/* dimension ids */
int npractices_dim;
int ncounty_ids_dim;
int nyears_dim;
/* dimension lengths */
size_t npractices_len = 1;
size_t ncounty_ids_len = NC_UNLIMITED;
size_t nyears_len = 2;
/* variable ids */
int crop_harvest_id;
/* rank (number of dimensions) for each variable */
# define RANK_crop_harvest 3
/* variable shapes */
int crop_harvest_dims[RANK_crop_harvest];
/* enter define mode */
stat = nc_create("ca2.nc", NC_CLOBBER|NC_NETCDF4, &ncid);
check_err(stat,__LINE__,__FILE__);
root_grp = ncid;
stat = nc_def_compound(root_grp, sizeof(CROP_HARVESTING_ACREAGE),
"CROP_HARVESTING_ACREAGE", &CROP_HARVESTING_ACREAGE_typ);
check_err(stat,__LINE__,__FILE__);
{
static int planted_acres_dims[1] = {
3}; static int harvested_acres_dims[1] = {
3}; static int yield_dims[1] = {
3}; static int percent_comp_dims[1] = {
3}; stat = nc_insert_compound(root_grp, CROP_HARVESTING_ACREAGE_typ,
"county_id", NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,county_id), NC_USHORT);
check_err(stat,__LINE__,__FILE__);
stat = nc_insert_compound(root_grp, CROP_HARVESTING_ACREAGE_typ, "year",
NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,year), NC_USHORT);
check_err(stat,__LINE__,__FILE__);
stat = nc_insert_compound(root_grp, CROP_HARVESTING_ACREAGE_typ,
"prac_code", NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,prac_code), NC_UBYTE);
check_err(stat,__LINE__,__FILE__);
stat = nc_insert_array_compound(root_grp, CROP_HARVESTING_ACREAGE_typ,
"planted_acres", NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,planted_acres),
NC_USHORT, 1, planted_acres_dims); check_err(stat,__LINE__,__FILE__);
stat = nc_insert_array_compound(root_grp, CROP_HARVESTING_ACREAGE_typ,
"harvested_acres", NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,harvested_acres),
NC_USHORT, 1, harvested_acres_dims); check_err(stat,__LINE__,__FILE__);
stat = nc_insert_array_compound(root_grp, CROP_HARVESTING_ACREAGE_typ,
"yield", NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,yield), NC_FLOAT, 1,
yield_dims); check_err(stat,__LINE__,__FILE__);
stat = nc_insert_array_compound(root_grp, CROP_HARVESTING_ACREAGE_typ,
"percent_comp", NC_COMPOUND_OFFSET(CROP_HARVESTING_ACREAGE,percent_comp),
NC_FLOAT, 1, percent_comp_dims); check_err(stat,__LINE__,__FILE__);
}
/* define dimensions */
stat = nc_def_dim(root_grp, "npractices", npractices_len, &npractices_dim);
check_err(stat,__LINE__,__FILE__);
stat = nc_def_dim(root_grp, "ncounty_ids", ncounty_ids_len,
&ncounty_ids_dim);
check_err(stat,__LINE__,__FILE__);
stat = nc_def_dim(root_grp, "nyears", nyears_len, &nyears_dim);
check_err(stat,__LINE__,__FILE__);
/* define variables */
crop_harvest_dims[0] = ncounty_ids_dim;
crop_harvest_dims[1] = nyears_dim;
crop_harvest_dims[2] = npractices_dim;
stat = nc_def_var(root_grp, "crop_harvest", CROP_HARVESTING_ACREAGE_typ,
RANK_crop_harvest, crop_harvest_dims, &crop_harvest_id);
check_err(stat,__LINE__,__FILE__);
/* assign per-variable attributes */
{ /* long_name */
stat = nc_put_att_text(root_grp, crop_harvest_id, "long_name", 55, "crop
harvest attributes by\ncounty ID, year and practice");
check_err(stat,__LINE__,__FILE__);
}
/* leave define mode */
stat = nc_enddef (root_grp);
check_err(stat,__LINE__,__FILE__);
/* assign variable data */
{
CROP_HARVESTING_ACREAGE crop_harvest_data[4] = {{111, 2011, 13, 11, 12, 13,
101, 102, 103, 11.5, 12.5, 13.5, 0.11, 0.12, 0.13}, {222, 2011, 23, 21, 22, 23,
201, 202, 203, 21.5, 22.5, 23.5, 0.21, 0.22, 0.23}, {333, 2011, 33, 31, 32, 33,
301, 302, 303, 31.5, 32.5, 33.5, 0.31, 0.32, 0.33}, {444, 2011, 43, 41, 42, 43,
401, 402, 403, 41.5, 42.5, 43.5, 0.41, 0.42, 0.43}} ;
size_t crop_harvest_startset[3] = {0, 0, 0} ;
size_t crop_harvest_countset[3] = {2, 2, 1} ;
stat = nc_put_vara(root_grp, crop_harvest_id, crop_harvest_startset,
crop_harvest_countset, crop_harvest_data);
check_err(stat,__LINE__,__FILE__);
}
stat = nc_close(root_grp);
check_err(stat,__LINE__,__FILE__);
return 0;
}
NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.