Don et al,
On Tue, Dec 10, 2013 at 9:42 AM, Don Murray <don.murray@xxxxxxxx
<mailto:don.murray@xxxxxxxx>> wrote:
Roland-
The values will be relative to the time unit and if that has
changed, then so will the values. Are the time units different
between the original files and the aggregation? If you look at the
actual "dates" described by the values, are they correct?
Well, that's my point. The time unit is the time unit of the first file
so the time values for the first 12 should be the same as they are in
the first file.
Aggregation:
double time(time) ;
time:bounds = "time_bnds" ;
time:units = "days since 1982-04-01 00:00:00" ;
time:calendar = "JULIAN" ;
time:axis = "T" ;
time:long_name = "time" ;
time:standard_name = "time" ;
File:
double time(time) ;
time:bounds = "time_bnds" ;
time:units = "days since 1982-04-01 00:00:00" ;
time:calendar = "JULIAN" ;
time:axis = "T" ;
time:long_name = "time" ;
time:standard_name = "time"
So in the resulting aggregation the dates are "wrong". The values in
the coordinate variable should not change until the 13th value.
Since you are only aggregating on the time dimension, that's all
that gets changed, hence time_bnds stays with the original values.
I'm not sure if that's a feature or a bug. ;-)
Bug or needed feature enchancement, IMO. CF relates the two variables
so the aggregation machinery should too.
Roland
Don
On 12/10/13 8:31 AM, Roland Schweitzer - NOAA Affiliate wrote:
Hi,
This will run a little long, so thanks for bearing with me.
I pulled down these 6 files:
ftp://nomads.gfdl.noaa.gov/__gfdl_cm2_1/CM2.1U_CDAef_v1.0___apf/r1/pp/atmos/ts/monthly/__tas_CLIVAR_atm_monthly.198204-__198303.nc
<ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/CM2.1U_CDAef_v1.0_apf/r1/pp/atmos/ts/monthly/tas_CLIVAR_atm_monthly.198204-198303.nc>
ftp://nomads.gfdl.noaa.gov/__gfdl_cm2_1/CM2.1U_CDAef_v1.0___apf/r1/pp/atmos/ts/monthly/__tas_CLIVAR_atm_monthly.198304-__198403.nc
<ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/CM2.1U_CDAef_v1.0_apf/r1/pp/atmos/ts/monthly/tas_CLIVAR_atm_monthly.198304-198403.nc>
ftp://nomads.gfdl.noaa.gov/__gfdl_cm2_1/CM2.1U_CDAef_v1.0___apf/r1/pp/atmos/ts/monthly/__tas_CLIVAR_atm_monthly.198404-__198503.nc
<ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/CM2.1U_CDAef_v1.0_apf/r1/pp/atmos/ts/monthly/tas_CLIVAR_atm_monthly.198404-198503.nc>
ftp://nomads.gfdl.noaa.gov/__gfdl_cm2_1/CM2.1U_CDAef_v1.0___apf/r1/pp/atmos/ts/monthly/zg___CLIVAR_atm_monthly.198204-__198303.nc
<ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/CM2.1U_CDAef_v1.0_apf/r1/pp/atmos/ts/monthly/zg_CLIVAR_atm_monthly.198204-198303.nc>
ftp://nomads.gfdl.noaa.gov/__gfdl_cm2_1/CM2.1U_CDAef_v1.0___apf/r1/pp/atmos/ts/monthly/zg___CLIVAR_atm_monthly.198304-__198403.nc
<ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/CM2.1U_CDAef_v1.0_apf/r1/pp/atmos/ts/monthly/zg_CLIVAR_atm_monthly.198304-198403.nc>
ftp://nomads.gfdl.noaa.gov/__gfdl_cm2_1/CM2.1U_CDAef_v1.0___apf/r1/pp/atmos/ts/monthly/zg___CLIVAR_atm_monthly.198404-__198503.nc
<ftp://nomads.gfdl.noaa.gov/gfdl_cm2_1/CM2.1U_CDAef_v1.0_apf/r1/pp/atmos/ts/monthly/zg_CLIVAR_atm_monthly.198404-198503.nc>
If I build the aggregation using this XML
<?xml version="1.0"?>
<catalog
xmlns="http://www.unidata.__ucar.edu/namespaces/thredds/__InvCatalog/v1.0
<http://www.unidata.ucar.edu/namespaces/thredds/InvCatalog/v1.0>"
xmlns:xlink="http://www.w3.__org/1999/xlink
<http://www.w3.org/1999/xlink>" name="CLIVAR Datasets">
<service name="ipcc" base="" serviceType="compound">
<service name="ipcc_odap" serviceType="OpenDAP"
base="/thredds/dodsC/"/>
<service name="wcs" serviceType="WCS" base="/thredds/wcs/"/>
<service name="wms" serviceType="WMS" base="/thredds/wms/"/>
<service name="ncss" serviceType="NetcdfSubset"
base="/thredds/ncss/grid/"/>
<service name="ncml" serviceType="NCML"
base="/thredds/ncml/"/>
<service name="uddc" serviceType="UDDC"
base="/thredds/uddc/"/>
<service name="iso" serviceType="ISO" base="/thredds/iso/"/>
</service>
<dataset name="GFDL CM2.1 Seasonal-Interannual Experimental
Forecast">
<dataset name="CM2.1U_CDAef_v1.0_apf">
<dataset name="r1">
<dataset name="atmos">
<dataset ID="CM2.1U_CDAef_v1.0_apf r1 Atmosphere"
name="CM2.1U_CDAef_v1.0_apf r1 Atmosphere"
urlPath="CM2.1U_CDApf_v1.0___r1Atmos_wo_vars">
<dataType>Grid</dataType>
<property name="viewer"
value="http://data1.gfdl.noaa.__gov:8380/lasV7/getUI.do?data___url=http://data1.gfdl.noaa.__gov:8380/thredds/dodsC/CM2.1U___CDApf_v1.0_r1Atmos
<http://data1.gfdl.noaa.gov:8380/lasV7/getUI.do?data_url=http://data1.gfdl.noaa.gov:8380/thredds/dodsC/CM2.1U_CDApf_v1.0_r1Atmos>,
Visualize with Live Access Serve
r"/>
<serviceName>ipcc</__serviceName>
<netcdf
xmlns="http://www.unidata.__ucar.edu/namespaces/netcdf/__ncml-2.2
<http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2>">
<aggregation type="union">
<netcdf
xmlns="http://www.unidata.__ucar.edu/namespaces/netcdf/__ncml-2.2
<http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2>">
<aggregation dimName="time" type="joinExisting"
timeUnitsChange="true">
<scan
location="/home/users/rhs/__clivar/gfdl_cm2_1/CM2.1U___CDAef_v1.0_apf/r1/pp/atmos/ts/__monthly"
suffix="tas_*.nc"/>
</aggregation>
</netcdf>
<netcdf
xmlns="http://www.unidata.__ucar.edu/namespaces/netcdf/__ncml-2.2
<http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2>">
<aggregation dimName="time" type="joinExisting"
timeUnitsChange="true">
<scan
location="/home/users/rhs/__clivar/gfdl_cm2_1/CM2.1U___CDAef_v1.0_apf/r1/pp/atmos/ts/__monthly"
suffix="zg_*.nc"/>
</aggregation>
</netcdf>
</aggregation>
</netcdf>
</dataset>
</dataset>
</dataset>
</dataset>
</dataset>
</catalog>
I get a time axis and a time_bnds that looks like this:
Dataset {
Float64 time[time = 36];
Float64 time_bnds[time = 36][bnds = 2];
} CM2.1U_CDApf_v1.0_r1Atmos_wo___vars;
------------------------------__---------------
time[36]
28.0, 58.5, 89.0, 119.5, 150.5, 181.0, 211.5, 242.0, 272.5,
303.5, 333.0, 362.5, 393.0, 423.5, 454.0, 484.5, 515.5, 546.0,
576.5, 607.0, 637.5, 668.5, 698.5, 728.5, 759.0, 789.5, 820.0,
850.5, 881.5, 912.0, 942.5, 973.0, 1003.5, 1034.5, 1064.0, 1093.5
time_bnds[36][2]
[0], 0.0, 30.0
[1], 30.0, 61.0
[2], 61.0, 91.0
[3], 91.0, 122.0
[4], 122.0, 153.0
[5], 153.0, 183.0
[6], 183.0, 214.0
[7], 214.0, 244.0
[8], 244.0, 275.0
[9], 275.0, 306.0
[10], 306.0, 334.0
[11], 334.0, 365.0
[12], 0.0, 30.0
[13], 30.0, 61.0
[14], 61.0, 91.0
[15], 91.0, 122.0
[16], 122.0, 153.0
[17], 153.0, 183.0
[18], 183.0, 214.0
[19], 214.0, 244.0
[20], 244.0, 275.0
[21], 275.0, 306.0
[22], 306.0, 335.0
[23], 335.0, 366.0
[24], 0.0, 30.0
[25], 30.0, 61.0
[26], 61.0, 91.0
[27], 91.0, 122.0
[28], 122.0, 153.0
[29], 153.0, 183.0
[30], 183.0, 214.0
[31], 214.0, 244.0
[32], 244.0, 275.0
[33], 275.0, 306.0
[34], 306.0, 334.0
[35], 334.0, 365.0
In each of the of the original files the time coordinate looks
like this:
time = 15, 45.5, 76, 106.5, 137.5, 168, 198.5, 229, 259.5,
290.5, 320, 349.5 ;
So I would expect the aggregation time axis to start with 15.
Based on some emails in the list archive, I'm pretty sure the
time_bnds is a known issue. So the main questions how are the
values for the time axis calculated?
This is all being done with:
Implementation-Vendor: UCAR/Unidata
Implementation-Title: THREDDS Data Server (TDS)
Implementation-Version: 4.3.20
And for completeness, I know I can get close to what I want by
defining
the time coordinate and time bounds myself, but it seems like a
lot of
extra work.
<?xml version="1.0"?>
<catalog
xmlns="http://www.unidata.__ucar.edu/namespaces/thredds/__InvCatalog/v1.0
<http://www.unidata.ucar.edu/namespaces/thredds/InvCatalog/v1.0>"
xmlns:xlink="http://www.w3.__org/1999/xlink
<http://www.w3.org/1999/xlink>" name="CLIVAR Datasets">
<service name="ipcc" base="" serviceType="compound">
<service name="ipcc_odap" serviceType="OpenDAP"
base="/thredds/dodsC/"/>
<service name="wcs" serviceType="WCS" base="/thredds/wcs/"/>
<service name="wms" serviceType="WMS" base="/thredds/wms/"/>
<service name="ncss" serviceType="NetcdfSubset"
base="/thredds/ncss/grid/"/>
<service name="ncml" serviceType="NCML"
base="/thredds/ncml/"/>
<service name="uddc" serviceType="UDDC"
base="/thredds/uddc/"/>
<service name="iso" serviceType="ISO" base="/thredds/iso/"/>
</service>
<dataset name="GFDL CM2.1 Seasonal-Interannual Experimental
Forecast">
<dataset name="CM2.1U_CDAef_v1.0_apf">
<dataset name="r1">
<dataset name="atmos">
<dataset ID="CM2.1U_CDAef_v1.0_apf r1 Atmosphere"
name="CM2.1U_CDAef_v1.0_apf r1 Atmosphere"
urlPath="CM2.1U_CDApf_v1.0___r1Atmos">
<dataType>Grid</dataType>
<property name="viewer"
value="http://data1.gfdl.noaa.__gov:8380/lasV7/getUI.do?data___url=http://data1.gfdl.noaa.__gov:8380/thredds/dodsC/CM2.1U___CDApf_v1.0_r1Atmos
<http://data1.gfdl.noaa.gov:8380/lasV7/getUI.do?data_url=http://data1.gfdl.noaa.gov:8380/thredds/dodsC/CM2.1U_CDApf_v1.0_r1Atmos>,
Visualize with Live Access Serve
r"/>
<serviceName>ipcc</__serviceName>
<netcdf
xmlns="http://www.unidata.__ucar.edu/namespaces/netcdf/__ncml-2.2
<http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2>">
<aggregation type="union">
<netcdf
xmlns="http://www.unidata.__ucar.edu/namespaces/netcdf/__ncml-2.2
<http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2>">
<variable name="time" shape="time" type="float">
<attribute name="units" value="days since
1982-04-01 00:00:00"/>
<attribute name="bounds" value="tbnds"/>
<attribute name="_CoordinateAxisType"
value="Time"/>
<values start="15" increment="30.5"/>
</variable>
<variable name="time_bnds" shape="time bnds"
type="float">
<values>
0 30
30 61
61 91
91 122
122 153
153 183
183 214
214 244
244 275
275 306
306 334
334 365
365 395
395 426
426 456
456 487
487 518
518 548
548 579
579 609
609 640
640 671
671 700
700 731
731 761
761 792
792 822
822 853
853 884
884 914
914 945
945 975
975 1006
1006 1037
1037 1065
1065 1096
</values>
</variable>
<aggregation dimName="time" type="joinExisting"
timeUnitsChange="true">
<scan
location="/home/users/rhs/__clivar/gfdl_cm2_1/CM2.1U___CDAef_v1.0_apf/r1/pp/atmos/ts/__monthly"
suffix="tas_*.nc"/>
</aggregation>
</netcdf>
<netcdf
xmlns="http://www.unidata.__ucar.edu/namespaces/netcdf/__ncml-2.2
<http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2>">
<variable name="time" shape="time" type="float">
<attribute name="units" value="days since
1982-04-01 00:00:00"/>
<attribute name="bounds" value="tbnds"/>
<attribute name="_CoordinateAxisType"
value="Time"/>
<values start="15" increment="30.5"/>
</variable>
<variable name="time_bnds" shape="time bnds"
type="float">
<values>
0 30
30 61
61 91
91 122
122 153
153 183
183 214
214 244
244 275
275 306
306 334
334 365
365 395
395 426
426 456
456 487
487 518
518 548
548 579
579 609
609 640
640 671
671 700
700 731
731 761
761 792
792 822
822 853
853 884
884 914
914 945
945 975
975 1006
1006 1037
1037 1065
1065 1096
</values>
</variable>
<aggregation dimName="time" type="joinExisting"
timeUnitsChange="true">
<scan
location="/home/users/rhs/__clivar/gfdl_cm2_1/CM2.1U___CDAef_v1.0_apf/r1/pp/atmos/ts/__monthly"
suffix="zg_*.nc"/>
</aggregation>
</netcdf>
</aggregation>
</netcdf>
</dataset>
</dataset>
</dataset>
</dataset>
</dataset>
</catalog>
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--
Don Murray
NOAA/ESRL/PSD and CIRES
303-497-3596 <tel:303-497-3596>
http://www.esrl.noaa.gov/psd/__people/don.murray/
<http://www.esrl.noaa.gov/psd/people/don.murray/>
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