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.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/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.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";
xmlns: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,
Visualize with Live Access Serve
r"/>
<serviceName>ipcc</serviceName>
<netcdf xmlns="
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";>
<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";>
<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";
xmlns: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,
Visualize with Live Access Serve
r"/>
<serviceName>ipcc</serviceName>
<netcdf xmlns="
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";>
<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";>
<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>
