WPS Download NetCDF¶

Installing the WPS Download NetCDF module¶

The WPS Download NetCDF module depends on 3 extensions:

1. Web Processing Service (WPS)

2. WPS Download plugin

3. NetCDF Output Format

If you haven’t installed already, visit the website download page, locate your release, and download:

1. geoserver-2.27.x-wps-plugin.zip containing the WPS extension.

2. geoserver-2.27.x-wps-download-plugin.zip containing the WPS Download extension.

3. geoserver-2.27.x-netcdf-out-plugin.zip containing the NetCDF Output extension.

Then:

1. Download the WPS Download NetCDF community module from the nightly GeoServer community module builds.

   Warning

   Make sure to match the version of the extension to the version of the GeoServer instance!

2. Extract all the contents of the archives into the WEB-INF/lib directory of the GeoServer installation.

3. Restart GeoServer

Module description¶

This module adds further capabilities to the Raw data download processes Raw Data Download process of the WPS Download plugin extension, by supporting dimension-aware filtering and NetCDF output. It enables users to download spatio-temporal grid coverages (such as climate or remote sensing data, for example) in NetCDF format, while filtering the data based on specific dimension values—like time, elevation, or other custom-defined dimensions. The filter is applied directly to the multidimensional data source. For example, in the case of an ImageMosaic, it targets the mosaic index to select multiple matching slices, which are then combined into the final NetCDF output file.

Relevant parameters of the Raw Data Download process:

1. layerName - name of the raster layer that has enabled dimensions (i.e. time, elevation)

2. filter - a filter containing subsetting on the attributes associated to the enabled dimensions

3. outputFormat - The mimeType of the requested output: application/x-netcdf or application/x-netcdf4 (if NetCDF-4 is enabled)

<ows:Identifier>gs:Download</ows:Identifier>
<wps:DataInputs>
  <wps:Input>
    <ows:Identifier>layerName</ows:Identifier>
    <wps:Data>
      <wps:LiteralData>it.geosolutions:watertemperature</wps:LiteralData>
    </wps:Data>
  </wps:Input>
  <wps:Input>
    <ows:Identifier>filter</ows:Identifier>
    <wps:Data>
      <wps:ComplexData mimeType="text/plain; subtype=cql"><![CDATA[ingestion >= '2013-09-11T00:00:00.000Z' and ingestion <= '2013-09-12T00:00:00.000Z' and elevation=0]]></wps:ComplexData>
    </wps:Data>
  </wps:Input>
  <wps:Input>
    <ows:Identifier>outputFormat</ows:Identifier>
    <wps:Data>
      <wps:LiteralData>application/x-netcdf</wps:LiteralData>
    </wps:Data>
  </wps:Input>
</wps:DataInputs>

Writing parameters¶

By default, the Settings configured in the NetCDF Output Settings of the layer (i.e. DataPacking, Compression level, Chunk Shuffling, variable names) are as Default writing parameters. Optionally, they can be overridden via explicit writeParameters input.

The writeParameters input element of a process execution allows to specify parameters to be applied by the outputFormat encoder when producing the output file. Writing parameters are listed as multiple <dwn:Parameter key="writingParameterName">value</dwn:Parameter> within a <dwn:Parameters> parent element. See the below xml containing full syntax of a valid example for NetCDF output format:

<wps:Input>
  <ows:Identifier>writeParameters</ows:Identifier>
    <wps:Data>
       <wps:ComplexData xmlns:dwn="http://geoserver.org/wps/download">
         <dwn:Parameters>
           <dwn:Parameter key="compression">5</dwn:Parameter>
           <dwn:Parameter key="shuffle">true</dwn:Parameter>
           <dwn:Parameter key="dataPacking">SHORT</dwn:Parameter>
           <dwn:Parameter key="variableName">air_temperature</dwn:Parameter>
           <dwn:Parameter key="uom">K</dwn:Parameter>
           <dwn:Parameter key="copyGlobalAttributes">true</dwn:Parameter>
           <dwn:Parameter key="copyVariableAttributes">true</dwn:Parameter>
         </dwn:Parameters>
       </wps:ComplexData>
    </wps:Data>
</wps:Input>

Note that the Shuffle and Compression parameters take effect only when the NetCDF-4 encoding is requested (using the application/x-netcdf4 MIME type).