Changes between Version 3 and Version 4 of NCMLUserStories


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Timestamp:
Apr 30, 2016 6:32:58 PM (6 years ago)
Author:
sixto
Comment:

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  • NCMLUserStories

    v3 v4  
    88
    99* [http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/ncml/ NetCDF Markup Language (NcML)]: NcML is an XML representation of netCDF metadata. NcML is similar to the netCDF CDL (network Common data form Description Language), except, of course, it uses XML syntax.
    10    * '''How to define new dimensions or correct/modify existing ones?'''
     10
     11== Examples ==
     12
     13* '''How to modify the values of a variable in a netcdf file?'''
     14   Ncml could be a useful tool to manipulate netcdf files. In this example, we are going to describe how to modify the values of a particular variable (rlat) in an existing netcdf file (tas.nc).
     15
     16   For this purpuse it is necessary to generate a ncml that refers to that particular netcdf, by adding a location argument. Then, we just need to specify the variable name that we want to change, their values  and the separator between them. The ncml file will look something like this:
     17{{{
     18<?xml version="1.0" encoding="UTF-8"?>
     19<ncml:netcdf xmlns:ncml="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2" location="tas.nc">
     20    <ncml:variable name="rlat">
     21    <ncml:values separator=",">
     22                0.883846282958984, 1.10384750366211, 1.32384872436523, 1.54384613037109, 1.76384735107422, 1.98384857177734, 2.2038459777832, 2.42384719848633, 2.64384841918945, 2.86384773254395, 3.08384704589844, 3.30384826660156, 3.52384757995605, 3.74384689331055, 3.96384811401367, 4.18384742736816, 4.40384674072266, 4.62384796142578, 4.84384727478027, 5.06384658813477, 5.28384780883789, 5.50384712219238, 5.72384834289551, 5.94384765625, 6.16384696960449, 6.38384819030762, 6.60384750366211, 6.8238468170166, 7.04384803771973, 7.26384735107422, 7.48384666442871,7.70384788513184, 7.92384719848633, 8.14384841918945, 8.36384773254395, 8.58384704589844, 8.80384826660156, 9.02384757995605, 9.24384689331055, 9.46384811401367, 9.68384742736816, 9.90384674072266, 10.1238479614258, 10.3438472747803, 10.5638465881348, 10.7838478088379, 11.0038471221924, 11.2238483428955, 11.44384765625, 11.6638469696045, 11.8838481903076, 12.1038475036621, 12.3238468170166, 12.5438480377197, 12.7638473510742, 12.9838466644287, 13.2038478851318, 13.4238471984863, 13.6438484191895, 13.8638477325439, 14.0838470458984, 14.3038482666016, 14.5238475799561, 14.7438468933105, 14.9638481140137, 15.1838474273682, 15.4038467407227, 15.6238479614258, 15.8438472747803, 16.0638465881348, 16.2838478088379, 16.5038471221924, 16.7238483428955, 16.94384765625, 17.1638469696045, 17.3838481903076, 17.6038475036621, 17.8238468170166, 18.0438480377197, 18.2638473510742, 18.4838466644287, 18.7038478851318, 18.9238471984863, 19.1438484191895, 19.3638477325439, 19.5838470458984, 19.8038482666016, 20.0238475799561, 20.2438468933105, 20.4638481140137, 20.6838474273682, 20.9038467407227, 21.1238479614258, 21.3438472747803, 21.5638465881348, 21.7838478088379, 22.0038471221924, 22.2238464355469, 22.44384765625, 22.6638469696045, 22.883846282959, 23.1038475036621, 23.3238487243652, 23.5438461303711, 23.7638473510742, 23.9838485717773, 24.2038478851318, 24.4238471984863, 24.6438484191895, 24.8638477325439, 25.0838470458984, 25.3038482666016, 25.5238475799561, 25.7438468933105, 25.9638481140137, 26.1838474273682, 26.4038467407227, 26.6238479614258, 26.8438472747803, 27.0638465881348, 27.2838478088379, 27.5038471221924, 27.7238464355469, 27.94384765625, 28.1638469696045, 28.383846282959, 28.6038475036621, 28.8238468170166, 29.0438480377197, 29.2638473510742, 29.4838485717773, 29.7038478851318, 29.9238471984863, 30.1438484191895, 30.3638477325439, 30.5838470458984, 30.8038482666016, 31.0238475799561, 31.2438468933105, 31.4638481140137, 31.6838474273682, 31.9038467407227, 32.1238479614258, 32.3438491821289, 32.5638465881348, 32.7838478088379, 33.003849029541, 33.2238464355469, 33.44384765625, 33.6638488769531, 33.883846282959, 34.1038475036621, 34.3238487243652, 34.5438461303711, 34.7638473510742, 34.9838485717773, 35.2038459777832, 35.4238471984863, 35.6438484191895, 35.8638458251953, 36.0838470458984, 36.3038482666016, 36.5238456726074, 36.7438468933105, 36.9638481140137, 37.1838455200195, 37.4038467407227
     23                </ncml:values>
     24  </ncml:variable>
     25</ncml:netcdf>
     26}}}
     27   In order to save the changes in a new netcdf file, we can use toolsUI.
     28{{{
     29java -cp /software/meteo/jar/toolsUI-4.6.5.jar ucar.nc2.write.Nccopy --input rlat_new.ncml --output tas_new.nc --format netcdf4_classic -d 4 -sh
     30}}}
     31
     32* '''How to define new dimensions or correct/modify existing ones?'''
    1133{{{
    1234<?xml version="1.0" encoding="UTF-8"?>
     
    1739</ncml:netcdf>
    1840}}}
    19    * '''How to define new variables or correct/modify existing ones?'''
     41
     42* '''How to define new variables or correct/modify existing ones?'''
    2043{{{
    2144<?xml version="1.0" encoding="UTF-8"?>
     
    5174</ncml:netcdf>
    5275}}}
    53    * '''How to aggregate datasets?'''
    54 {{{
    55 <!--
    56 Union of variables stored en different files
    57 -->
     76
     77* '''How to aggregate datasets?'''
     78{{{
    5879<?xml version="1.0" encoding="UTF-8"?>
    5980<ncml:netcdf xmlns:ncml="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2" location="dods://opendap.knmi.nl/knmi/thredds/dodsC/e-obs_0.25regular/pp_0.25deg_reg_v12.0.nc">
     
    6990     </ncml:aggregation>
    7091</ncml:netcdf>
    71 
    72 <!--
    73 Union along an existing dimension
    74 -->
    75 
     92}}}
     93
     94* '''How to aggregate files along an existing dimension?'''
     95{{{
    7696<?xml version="1.0" encoding="UTF-8"?>
    7797<ncml:netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2">
     
    109129        </ncml:aggregation>
    110130</ncml:netcdf>
    111 
    112 
    113 <!--
    114 Union along a new dimension
    115 -->
    116 
     131}}}
     132
     133* '''How to aggregate files along a new dimension?'''
     134{{{
    117135<?xml version="1.0" encoding="UTF-8"?>
    118136<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2">
     
    185203}}}
    186204
    187 == Examples ==
    188 * '''How to modify the values of a variable in a netcdf file?'''
    189    Ncml could be a useful tool to manipulate netcdf files. In this example, we are going to describe how to modify the values of a particular variable (rlat) in an existing netcdf file (tas.nc).
    190 
    191    For this purpuse it is necessary to generate a ncml that refers to that particular netcdf, by adding a location argument. Then, we just need to specify the variable name that we want to change, their values  and the separator between them. The ncml file will look something like this:
    192 {{{
    193 <?xml version="1.0" encoding="UTF-8"?>
    194 <ncml:netcdf xmlns:ncml="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2" location="tas.nc">
    195     <ncml:variable name="rlat">
    196     <ncml:values separator=",">
    197                 0.883846282958984, 1.10384750366211, 1.32384872436523, 1.54384613037109, 1.76384735107422, 1.98384857177734, 2.2038459777832, 2.42384719848633, 2.64384841918945, 2.86384773254395, 3.08384704589844, 3.30384826660156, 3.52384757995605, 3.74384689331055, 3.96384811401367, 4.18384742736816, 4.40384674072266, 4.62384796142578, 4.84384727478027, 5.06384658813477, 5.28384780883789, 5.50384712219238, 5.72384834289551, 5.94384765625, 6.16384696960449, 6.38384819030762, 6.60384750366211, 6.8238468170166, 7.04384803771973, 7.26384735107422, 7.48384666442871,7.70384788513184, 7.92384719848633, 8.14384841918945, 8.36384773254395, 8.58384704589844, 8.80384826660156, 9.02384757995605, 9.24384689331055, 9.46384811401367, 9.68384742736816, 9.90384674072266, 10.1238479614258, 10.3438472747803, 10.5638465881348, 10.7838478088379, 11.0038471221924, 11.2238483428955, 11.44384765625, 11.6638469696045, 11.8838481903076, 12.1038475036621, 12.3238468170166, 12.5438480377197, 12.7638473510742, 12.9838466644287, 13.2038478851318, 13.4238471984863, 13.6438484191895, 13.8638477325439, 14.0838470458984, 14.3038482666016, 14.5238475799561, 14.7438468933105, 14.9638481140137, 15.1838474273682, 15.4038467407227, 15.6238479614258, 15.8438472747803, 16.0638465881348, 16.2838478088379, 16.5038471221924, 16.7238483428955, 16.94384765625, 17.1638469696045, 17.3838481903076, 17.6038475036621, 17.8238468170166, 18.0438480377197, 18.2638473510742, 18.4838466644287, 18.7038478851318, 18.9238471984863, 19.1438484191895, 19.3638477325439, 19.5838470458984, 19.8038482666016, 20.0238475799561, 20.2438468933105, 20.4638481140137, 20.6838474273682, 20.9038467407227, 21.1238479614258, 21.3438472747803, 21.5638465881348, 21.7838478088379, 22.0038471221924, 22.2238464355469, 22.44384765625, 22.6638469696045, 22.883846282959, 23.1038475036621, 23.3238487243652, 23.5438461303711, 23.7638473510742, 23.9838485717773, 24.2038478851318, 24.4238471984863, 24.6438484191895, 24.8638477325439, 25.0838470458984, 25.3038482666016, 25.5238475799561, 25.7438468933105, 25.9638481140137, 26.1838474273682, 26.4038467407227, 26.6238479614258, 26.8438472747803, 27.0638465881348, 27.2838478088379, 27.5038471221924, 27.7238464355469, 27.94384765625, 28.1638469696045, 28.383846282959, 28.6038475036621, 28.8238468170166, 29.0438480377197, 29.2638473510742, 29.4838485717773, 29.7038478851318, 29.9238471984863, 30.1438484191895, 30.3638477325439, 30.5838470458984, 30.8038482666016, 31.0238475799561, 31.2438468933105, 31.4638481140137, 31.6838474273682, 31.9038467407227, 32.1238479614258, 32.3438491821289, 32.5638465881348, 32.7838478088379, 33.003849029541, 33.2238464355469, 33.44384765625, 33.6638488769531, 33.883846282959, 34.1038475036621, 34.3238487243652, 34.5438461303711, 34.7638473510742, 34.9838485717773, 35.2038459777832, 35.4238471984863, 35.6438484191895, 35.8638458251953, 36.0838470458984, 36.3038482666016, 36.5238456726074, 36.7438468933105, 36.9638481140137, 37.1838455200195, 37.4038467407227
    198                 </ncml:values>
    199   </ncml:variable>
    200 </ncml:netcdf>
    201 }}}
    202    In order to save the changes in a new netcdf file, we can use toolsUI.
    203 {{{
    204 java -cp /software/meteo/jar/toolsUI-4.6.5.jar ucar.nc2.write.Nccopy --input rlat_new.ncml --output tas_new.nc --format netcdf4_classic -d 4 -sh
    205 }}}