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| − | == Overview ==
| + | <!-- CATEGORIES --> |
| − | Geospatial Data Processing takes advantage of the OGC Web Processing Service (WPS) as web interface to allow for the dynamic deployment of user processes. In this case the WPS chosen is the [http://52north.org/communities/geoprocessing/wps/index.html 52° North WPS], allowing the development and deployment of user “algorithms”. Is dimostrated that such “algorithms” can be developed to be processed exploiting the powerful and distributed framework offered by [http://hadoop.apache.org/mapreduce/ Apache™ Hadoop™ MapReduce]
| + | [[Category: gCube Spatial Data Infrastructure]] |
| | + | <!-- CATEGORIES --> |
| | | | |
| − | Thus was born '''''WPS-hadoop'''''.
| + | {| align="right" |
| | + | ||__TOC__ |
| | + | |} |
| | | | |
| − | == Key Features ==
| + | gCube Spatial Data Processing offers a rich array of data analytics methods via OGC Web Processing Service (WPS). |
| − | WPS-hadoop offers a web interface to access the algorithms from external HTTP clients through three different kind of requests, made available to 52 North WPS:
| + | |
| | | | |
| − | - The '''GetCapabilities''' operation provides access to general information about a live WPS implementation, and lists the operations and access methods supported by that implementation. 52N WPS supports the GetCapabilities operation via HTTP GET and POST.
| + | == Overview == |
| | + | Geospatial Data Processing takes advantage of the OGC Web Processing Service (WPS) as web interface. |
| | + | It is implemented by relying on the [[Data Mining Facilities | gCube platform for data analytics]]. |
| | | | |
| − | - The '''DescribeProcess''' operation allows WPS clients to request a full description of one or more processes that can be executed by the service. This description includes the input and output parameters and formats and can be used to automatically build a user interface to capture the parameter values to be used to execute a process.
| + | [[File:Spatial_Data_Processing.png|400px|Overall Architecture]] |
| | | | |
| − | - The '''Execute''' operation allows WPS clients to run a specified process implemented by the server, using the input parameter values provided and returning the output values produced. Inputs can be included directly in the Execute request, or reference web accessible resources.
| + | == Key Features == |
| − | | + | |
| − | | + | |
| − | == Design == | + | |
| − | Extending the AbstractAlgorithm class (by 52N) we have created a new abstract class called HadoopAbstractAlgorithm where the Business Logic, hidden to the developer, is used to execute the process creating a Job for the hadoop framework.
| + | |
| − | | + | |
| − | | + | |
| − | [[Image:blocks.png]]
| + | |
| − | | + | |
| − | | + | |
| − | === Develop a custom process ===
| + | |
| − | The custom process class has to extend HadoopAbstractAlgorithm which allows you to specify the Hadoop Configuration parameters (e.g. from XML files), the Mapper and Reducer classes, Input Paths, Output Path, all the operations needed before to run the process and the way to retrieve the results.
| + | |
| − | By using HadoopAbstractAlgorithm, you need to fill these simple methods:
| + | |
| − | | + | |
| − | * protected Class<? extends Mapper<?, ?, LongWritable, Text>> getMapper()
| + | |
| − | | + | |
| − | This method returns the class to be used as Mapper;
| + | |
| − | | + | |
| − | * protected Class<? extends Reducer<LongWritable, Text, ?, ?>> getReducer()
| + | |
| − | | + | |
| − | This method returns the class to be used as Reducer (if exists);
| + | |
| − | * protected Path[] getInputPaths(Map<String, List<IData>> inputData)
| + | |
| − | | + | |
| − | This method allows to the business logic to know the exact input path(s) to pass to the Hadoop framework;
| + | |
| − | | + | |
| − | * protected String getOutputPath()
| + | |
| − | | + | |
| − | This method allows to the business logic to know the exact output path to pass to the Hadoop framework;
| + | |
| − | | + | |
| − | * protected Map buildResults()
| + | |
| − | | + | |
| − | This method is called by the business logic method to pass build output that the WPS does expect;
| + | |
| − | | + | |
| − | * public void prepareToRun(Map<String, List<IData>> inputData)
| + | |
| − | | + | |
| − | This method has to be filled by all the operations to do before to run the Hadoop Job (e.g. WPS input validation);
| + | |
| − | | + | |
| − | * protected JobConf getJobConf()
| + | |
| − | | + | |
| − | This method allows the user to specify all the configuration resources for (from) Hadoop framework (e.g. XML conf files).
| + | |
| − | | + | |
| − | [[Image:HadoopAbstractAlgorithm.png]]
| + | |
| − | | + | |
| − | === Deploy custom process ===
| + | |
| − | WPS-hadoop is deployed over Tomcat container.
| + | |
| − | | + | |
| − | In order to deploy the recently developed process, you need to:
| + | |
| − | # Export in a jar file the process.
| + | |
| − | # Copy the exported lib into the WEB-INF/lib directory.
| + | |
| − | # Restart tomcat.
| + | |
| − | #:Next, we need to register the newly created algorithm:
| + | |
| − | # Go to <nowiki>http://localhost:yourport/wps/ , e.g.http://localhost:8080/wps/.</nowiki>
| + | |
| − | # Click on 52n WPSAdmin console.
| + | |
| − | # Login with:
| + | |
| − | #:* Username: wps
| + | |
| − | #:* Password: wps
| + | |
| − | #:The Web Admin Console lets you change the basic configuration of the WPS and upload processes.
| + | |
| − | # Click on Algorithm Repository --> Properties (the '+' sign).
| + | |
| − | # Click on the Green '+' to register your process: Type in the left field Algorithm and in the right field the fully qualified class name of your created class (i.e. package + class name, e.g. org.n52.wps.demo.ConvexHullDemo).
| + | |
| − | # Click on the save icon (the 'disk').
| + | |
| − | # Next, Click on the top left on 'Save and Activate configuration'.
| + | |
| − | # Your new Process is now available, test it under: <nowiki>http://localhost:yourport/wps/WebProcessingService?Request=GetCapabilities&Service=WPS or directly http://localhost:yourport/wps/test.hmtl.</nowiki>
| + | |
| − | | + | |
| − | | + | |
| − | N.B. Alternatively to the step 1. you can follow steps 4. , 5. and 6. first, then click on Upload Process and pick the .java file of your just developed process. Then follow from step 2 onwards.
| + | |
| − | | + | |
| − | = Some complete examples =
| + | |
| − | | + | |
| − | | + | |
| − | ===The Bathymetry Algorithm ===
| + | |
| − | | + | |
| − | Here is a complete description of the use of WPS-hadoop library, through the example of Bathymetry retrieving from a netCDF file.
| + | |
| − | An input file containing a series of coordinate pairs will generate a file of "z" (bathymetry) value for the given x,y pair.
| + | |
| − | Actually the netCDF file is specified inside the mapper java source. A future (if needed) improvement could be pass this url as another WPS parameter.
| + | |
| − | | + | |
| − | | + | |
| − | ==== Class Diagram ====
| + | |
| − | [[Image:WPSClassDiagram.png|1500px]]
| + | |
| − | | + | |
| − | ==== BathymetryAlgorithm.xml ====
| + | |
| − | This file must be named exactly like the .java one.
| + | |
| − | | + | |
| − | <source lang="xml">
| + | |
| − | <?xml version="1.0" encoding="UTF-8"?>
| + | |
| − | <wps:ProcessDescriptions xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:xlink="http://www.w3.org/1999/xlink"
| + | |
| − | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://geoserver.itc.nl:8080/wps/schemas/wps/1.0.0/wpsDescribeProcess_response.xsd" xml:lang="en-US" service="WPS" version="1.0.0">
| + | |
| − | <ProcessDescription wps:processVersion="1.0.0" storeSupported="true" statusSupported="false">
| + | |
| − | <ows:Identifier>com.terradue.wps.BathymetryAlgorithm</ows:Identifier>
| + | |
| − | <ows:Title>Bathymetry Algorithm</ows:Title>
| + | |
| − | <ows:Abstract>by Hadoop</ows:Abstract>
| + | |
| − | <ows:Metadata xlink:title="Bathymetry" />
| + | |
| − | <DataInputs>
| + | |
| − | <Input minOccurs="1" maxOccurs="1">
| + | |
| − | <ows:Identifier>InputFile</ows:Identifier>
| + | |
| − | <ows:Title>InputFile</ows:Title>
| + | |
| − | <ows:Abstract>URL to a file containing x,y parameters</ows:Abstract>
| + | |
| − | <LiteralData>
| + | |
| − | <ows:DataType ows:reference="xs:string"></ows:DataType>
| + | |
| − | <ows:AnyValue/>
| + | |
| − | </LiteralData>
| + | |
| − | </Input>
| + | |
| − | </DataInputs>
| + | |
| − | <ProcessOutputs>
| + | |
| − | <Output>
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | <ows:Title>result</ows:Title>
| + | |
| − | <ows:Abstract>result</ows:Abstract>
| + | |
| − | <LiteralOutput>
| + | |
| − | <ows:DataType ows:reference="xs:string"/>
| + | |
| − | </LiteralOutput>
| + | |
| − | </Output>
| + | |
| − | </ProcessOutputs>
| + | |
| − | </ProcessDescription>
| + | |
| − | </wps:ProcessDescriptions>
| + | |
| − | </source>
| + | |
| − | | + | |
| − | ==== Requests examples ====
| + | |
| − | | + | |
| − | This is an example of how to request the execution of the BathymetryAlgorithm.
| + | |
| − | | + | |
| − | ==== XML request example ====
| + | |
| − | | + | |
| − | <source lang="xml">
| + | |
| − | <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
| + | |
| − | <wps:Execute service="WPS" version="1.0.0" xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1"
| + | |
| − | xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://schemas.opengis.net/wps/1.0.0/wpsExecute_request.xsd">
| + | |
| − | <ows:Identifier>com.terradue.wps_hadoop.examples.bathymetry.BathymetryAlgorithm</ows:Identifier>
| + | |
| − | <wps:DataInputs>
| + | |
| − | <wps:Input>
| + | |
| − | <ows:Identifier>InputFile</ows:Identifier>
| + | |
| − | <ows:Title>Input file for Bathymetry</ows:Title>
| + | |
| − | <wps:Data>
| + | |
| − | <wps:LiteralData>http://t2-10-11-30-97.play.terradue.int:8888/wps/maps/coordinates</wps:LiteralData>
| + | |
| − | </wps:Data>
| + | |
| − | </wps:Input>
| + | |
| − | </wps:DataInputs>
| + | |
| − | <wps:ResponseForm>
| + | |
| − | <wps:ResponseDocument storeExecuteResponse="false">
| + | |
| − | <wps:Output asReference="false">
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | </wps:Output>
| + | |
| − | </wps:ResponseDocument>
| + | |
| − | </wps:ResponseForm>
| + | |
| − | </wps:Execute>
| + | |
| − | </source>
| + | |
| − | | + | |
| − | ==== Input parameter description ====
| + | |
| − | | + | |
| − | '''InputFile''': This file contains a series of x,y (-180< x < 180 and -90 < y < 90) pairs.
| + | |
| − | Every file's line will be taking over from a single mapper instance.
| + | |
| − | This is the InputFile required format:
| + | |
| − | <nowiki>
| + | |
| − | xa1 ya1 xa2 ya2 xa3 ya3 xa4 ya4...xan yan
| + | |
| − | xb1 yb1 xb2 yb2 xb3 yb3 xb4 yb4...xbm ybm
| + | |
| − | .
| + | |
| − | .
| + | |
| − | .
| + | |
| − | </nowiki>
| + | |
| − | | + | |
| − | ==== KVP (Key Value Pairs) request example ====
| + | |
| − | <nowiki>
| + | |
| − | http://t2-10-11-30-97.play.terradue.int:8888/wps/WebProcessingService?Request=Execute&service=WPS&version=1.0.0&language=en-CA&Identifier=com.terradue.wps_hadoop.examples.bathymetry.BathymetryAlgorithm&DataInputs=InputFile=http://t2-10-11-30-97.play.terradue.int:8888/wps/maps/coordinates</nowiki>
| + | |
| − | | + | |
| − | === Resampler Algorithm ===
| + | |
| − | | + | |
| − | ==== Class Diagram ====
| + | |
| − | [[Image:ResamplerAlgorithm.png|1500px]]
| + | |
| − | | + | |
| − | ==== ResamplerAlgorithm.xml ====
| + | |
| − | | + | |
| − | <source lang="xml">
| + | |
| − | <?xml version="1.0" encoding="UTF-8"?>
| + | |
| − | <wps:ProcessDescriptions xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:xlink="http://www.w3.org/1999/xlink"
| + | |
| − | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://geoserver.itc.nl:8080/wps/schemas/wps/1.0.0/wpsDescribeProcess_response.xsd" xml:lang="en-US" service="WPS" version="1.0.0">
| + | |
| − | <ProcessDescription wps:processVersion="1.0.0" storeSupported="true" statusSupported="false">
| + | |
| − | <ows:Identifier>com.terradue.wps_hadoop.examples.resampler.ResamplerAlgorithm</ows:Identifier>
| + | |
| − | <ows:Title>Resampler Algorithm</ows:Title>
| + | |
| − | <ows:Abstract>by Hadoop</ows:Abstract>
| + | |
| − | <ows:Metadata xlink:title="resampler" />
| + | |
| − | <DataInputs>
| + | |
| − | <Input minOccurs="1" maxOccurs="1">
| + | |
| − | <ows:Identifier>wcs_url</ows:Identifier>
| + | |
| − | <ows:Title>wcs_url</ows:Title>
| + | |
| − | <ows:Abstract>wcs_url</ows:Abstract>
| + | |
| − | <LiteralData>
| + | |
| − | <ows:DataType ows:reference="xs:string"></ows:DataType>
| + | |
| − | <ows:AnyValue/>
| + | |
| − | </LiteralData>
| + | |
| − | </Input>
| + | |
| − | <Input minOccurs="1" maxOccurs="1">
| + | |
| − | <ows:Identifier>resolution</ows:Identifier>
| + | |
| − | <ows:Title>resolution</ows:Title>
| + | |
| − | <ows:Abstract>resolution</ows:Abstract>
| + | |
| − | <LiteralData>
| + | |
| − | <ows:DataType ows:reference="xs:string"></ows:DataType>
| + | |
| − | <ows:AnyValue/>
| + | |
| − | </LiteralData>
| + | |
| − | </Input>
| + | |
| − | </DataInputs>
| + | |
| − | <ProcessOutputs>
| + | |
| − | <Output>
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | <ows:Title>result</ows:Title>
| + | |
| − | <ows:Abstract>result</ows:Abstract>
| + | |
| − | <LiteralOutput>
| + | |
| − | <ows:DataType ows:reference="xs:string"/>
| + | |
| − | </LiteralOutput>
| + | |
| − | </Output>
| + | |
| − | </ProcessOutputs>
| + | |
| − | </ProcessDescription>
| + | |
| − | </wps:ProcessDescriptions>
| + | |
| − | </source>
| + | |
| − | | + | |
| − | ==== Requests examples ====
| + | |
| − | | + | |
| − | This is an example of how to request the execution of the ResamplerAlgorithm.
| + | |
| − | | + | |
| − | ==== XML request example ====
| + | |
| − | | + | |
| − | <source lang="xml">
| + | |
| − | <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
| + | |
| − | <wps:Execute service="WPS" version="1.0.0" xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1"
| + | |
| − | xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://schemas.opengis.net/wps/1.0.0/wpsExecute_request.xsd">
| + | |
| − | <ows:Identifier>com.terradue.wps_hadoop.examples.resampler.ResamplerAlgorithm</ows:Identifier>
| + | |
| − | <wps:DataInputs>
| + | |
| − | <wps:Input>
| + | |
| − | <ows:Identifier>wcs_url</ows:Identifier>
| + | |
| − | <ows:Title>WCS product's URL to be resampled</ows:Title>
| + | |
| − | <wps:Data>
| + | |
| − | <wps:LiteralData>http://t2-10-11-30-98.play.terradue.int:8080/thredds/wcs/maps/SST_MED_SST_L4_NRT_OBSERVATIONS_010_004_c_2011-11-03_2011-11-04.nc
| + | |
| − | ?service=WCS&version=1.0.0&request=GetCoverage&COVERAGE=analysed_sst&bbox=-18,20,36,45&width=100&height=100&format=geotiff</wps:LiteralData>
| + | |
| − | </wps:Data>
| + | |
| − | </wps:Input>
| + | |
| − | <wps:Input>
| + | |
| − | <ows:Identifier>wcs_url</ows:Identifier>
| + | |
| − | <ows:Title>WCS product's URL to be resampled (in degrees)</ows:Title>
| + | |
| − | <wps:Data>
| + | |
| − | <wps:LiteralData>0.01666923868312760</wps:LiteralData>
| + | |
| − | </wps:Data>
| + | |
| − | </wps:Input>
| + | |
| − | </wps:DataInputs>
| + | |
| − | <wps:ResponseForm>
| + | |
| − | <wps:ResponseDocument storeExecuteResponse="false">
| + | |
| − | <wps:Output asReference="false">
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | </wps:Output>
| + | |
| − | </wps:ResponseDocument>
| + | |
| − | </wps:ResponseForm>
| + | |
| − | </wps:Execute>
| + | |
| − | </source>
| + | |
| − | | + | |
| − | ==== Input parameter description ====
| + | |
| − | | + | |
| − | '''wcs_url''': This should be an URL to a WCS to be queried to get a Coverage;
| + | |
| − | | + | |
| − | '''resolution''': This is the desired resolution in degrees for the downloaded Coverage.
| + | |
| − | | + | |
| − | ==== KVP (Key Value Pairs) request example ====
| + | |
| − | <nowiki>
| + | |
| − | http://t2-10-11-30-97.play.terradue.int:8888/wps/WebProcessingService?Request=Execute&service=WPS&version=1.0.0&language=en-CA&Identifier=com.terradue.wps_hadoop.examples.resampler.ResamplerAlgorithm&DataInputs=wcs_url=http://t2-10-11-30-98.play.terradue.int:8080/thredds/wcs/maps/SST_MED_SST_L4_NRT_OBSERVATIONS_010_004_c_2011-11-03_2011-11-04.nc?service=WCS&version=1.0.0&request=GetCoverage&COVERAGE=analysed_sst&bbox=-18,20,36,45&width=100&height=100&format=geotiff;resolution=0.01666923868312760</nowiki>
| + | |
| − | | + | |
| − | '''Before to submit this kind of request you need to encode it in this way:'''
| + | |
| − | | + | |
| − | <nowiki>
| + | |
| − | http://t2-10-11-30-97.play.terradue.int:8888/wps/WebProcessingService?Request=Execute&service=WPS&version=1.0.0&language=en-CA&Identifier=com.terradue.wps_hadoop.examples.resampler.ResamplerAlgorithm&DataInputs=wcs_url=http://t2-10-11-30-98.play.terradue.int:8080/thredds/wcs/maps/SST_MED_SST_L4_NRT_OBSERVATIONS_010_004_c_2011-11-03_2011-11-04.nc?service=WCS%25version=1.0.0%25request=GetCoverage%25COVERAGE=analysed_sst%25bbox=-18,20,36,45%25width=100%25height=
| + | |
| − | 100%25format=geotiff;resolution=0.01666923868312760
| + | |
| − | </nowiki>
| + | |
| − | | + | |
| − | | + | |
| − | ==== More information ====
| + | |
| − | | + | |
| − | In order to exploit the real potential of Hadoop, more than a request should be sent to the WPS concurrently.
| + | |
| − | | + | |
| − | === Intersection Algorithm ===
| + | |
| − | | + | |
| − | ==== Class Diagram ====
| + | |
| − | [[Image:IntersectionAlgorithm.png|500px]]
| + | |
| − | | + | |
| − | ==== IntersectionHadoopAlgorithm.xml ====
| + | |
| − | | + | |
| − | <source lang="xml">
| + | |
| − | <?xml version="1.0" encoding="UTF-8"?>
| + | |
| − | <wps:ProcessDescriptions xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://geoserver.itc.nl:8080/wps/schemas/wps/1.0.0/wpsDescribeProcess_response.xsd" xml:lang="en-US" service="WPS" version="1.0.0">
| + | |
| − | <ProcessDescription wps:processVersion="1.0.0" storeSupported="true" statusSupported="false">
| + | |
| − | <ows:Identifier>com.terradue.wps_hadoop.examples.IntersectionAlgorithm</ows:Identifier>
| + | |
| − | <ows:Title>Intersection Algorithm</ows:Title>
| + | |
| − | <ows:Abstract>Calculate Intersection Feature</ows:Abstract>
| + | |
| − | <ows:Metadata xlink:title="Intersection" />
| + | |
| − | <DataInputs>
| + | |
| − | <Input minOccurs="1" maxOccurs="1">
| + | |
| − | <ows:Identifier>Polygon1</ows:Identifier>
| + | |
| − | <ows:Title>Polygon1</ows:Title>
| + | |
| − | <ows:Abstract>Polygon 1 URL</ows:Abstract>
| + | |
| − | <LiteralData>
| + | |
| − | <ows:DataType ows:reference="xs:string"></ows:DataType>
| + | |
| − | <ows:AnyValue/>
| + | |
| − | </LiteralData>
| + | |
| − | </Input>
| + | |
| − | <Input minOccurs="1" maxOccurs="1">
| + | |
| − | <ows:Identifier>Polygon2</ows:Identifier>
| + | |
| − | <ows:Title>Polygon2</ows:Title>
| + | |
| − | <ows:Abstract>Polygon 2 URL</ows:Abstract>
| + | |
| − | <LiteralData>
| + | |
| − | <ows:DataType ows:reference="xs:string"></ows:DataType>
| + | |
| − | <ows:AnyValue/>
| + | |
| − | </LiteralData>
| + | |
| − | </Input>
| + | |
| − | </DataInputs>
| + | |
| − | <ProcessOutputs>
| + | |
| − | <Output>
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | <ows:Title>result</ows:Title>
| + | |
| − | <ows:Abstract>result</ows:Abstract>
| + | |
| − | <LiteralOutput>
| + | |
| − | <ows:DataType ows:reference="xs:string"/>
| + | |
| − | </LiteralOutput>
| + | |
| − | </Output>
| + | |
| − | </ProcessOutputs>
| + | |
| − | </ProcessDescription>
| + | |
| − | </wps:ProcessDescriptions>
| + | |
| − | </source>
| + | |
| − | | + | |
| − | ==== Requests examples ====
| + | |
| − | | + | |
| − | This is an example of how to request the execution of the ResamplerAlgorithm.
| + | |
| − | | + | |
| − | ==== XML request example ====
| + | |
| − | | + | |
| − | <source lang="xml">
| + | |
| − | <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
| + | |
| − | <wps:Execute service="WPS" version="1.0.0" xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1"
| + | |
| − | xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://schemas.opengis.net/wps/1.0.0/wpsExecute_request.xsd">
| + | |
| − | <ows:Identifier>com.terradue.wps_hadoop.examples.intersection.IntersectionHadoopAlgorithm</ows:Identifier>
| + | |
| − | <wps:DataInputs>
| + | |
| − | <wps:Input>
| + | |
| − | <ows:Identifier>Polygon1</ows:Identifier>
| + | |
| − | <ows:Title>First polygon to be intersected</ows:Title>
| + | |
| − | <wps:Data>
| + | |
| − | <wps:LiteralData>http://www.fao.org/figis/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=fifao:FAO_MAJOR&CQL_FILTER=fifao:F_AREA=21</wps:LiteralData>
| + | |
| − | </wps:Data>
| + | |
| − | </wps:Input>
| + | |
| − | <wps:Input>
| + | |
| − | <ows:Identifier>Polygon2</ows:Identifier>
| + | |
| − | <ows:Title>Second Polygon to be intersected</ows:Title>
| + | |
| − | <wps:Data>
| + | |
| − | <wps:LiteralData>http://geo.vliz.be/geoserver/Marbound/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=Marbound:eez&CQL_FILTER%3DINTERSECTS%28Marbound%3Athe_geom%2CPOLYGON%28%28-82.410003662+34.830001831%2C-42+34.830001831%2C-42+78.166666031%2C-82.410003662+78.166666031%2C-82.410003662+34.830001831%29%29%29</wps:LiteralData>
| + | |
| − | </wps:Data>
| + | |
| − | </wps:Input>
| + | |
| − | </wps:DataInputs>
| + | |
| − | <wps:ResponseForm>
| + | |
| − | <wps:ResponseDocument storeExecuteResponse="false">
| + | |
| − | <wps:Output asReference="false">
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | </wps:Output>
| + | |
| − | </wps:ResponseDocument>
| + | |
| − | </wps:ResponseForm>
| + | |
| − | </wps:Execute>
| + | |
| − | </source>
| + | |
| − | | + | |
| − | | + | |
| − | ==== Input parameter description ====
| + | |
| − | | + | |
| − | '''Polygon1''' and '''Polygon2''': URLs to some WFS where to get two features containing valid geometries.
| + | |
| − | | + | |
| − | ==== KVP (Key Value Pairs) request example ====
| + | |
| − | <nowiki>
| + | |
| − | http://t2-10-11-30-97.play.terradue.int:8888/wps/WebProcessingService?Request=Execute&service=WPS&version=1.0.0&language=en-CA&Identifier=com.terradue.wps_hadoop.examples.intersection.IntersectionHadoopAlgorithm&DataInputs=Polygon1=http://www.fao.org/figis/geoserver/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=fifao:FAO_MAJOR&CQL_FILTER=fifao:F_AREA=21;Polygon2=http://geo.vliz.be/geoserver/Marbound/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=Marbound:eez&CQL_FILTER%3DINTERSECTS%28Marbound%3Athe_geom%2CPOLYGON%28%28-82.410003662+34.830001831%2C-42+34.830001831%2C-42+78.166666031%2C-82.410003662+78.166666031%2C-82.410003662+34.830001831%29%29%29</nowiki>
| + | |
| − | | + | |
| − | '''Before to submit this kind of request you need to encode it in this way:'''
| + | |
| − | | + | |
| − | <nowiki>
| + | |
| − | http://localhost:8888/wps/WebProcessingService?Request=Execute&service=WPS&version=1.0.0&language=en-CA&Identifier=com.terradue.wps_hadoop.examples.intersection.IntersectionHadoopAlgorithm&DataInputs=Polygon1=http%3A%2F%2Fwww.fao.org%2Ffigis%2Fgeoserver%2Fows%3Fservice%3DWFS%26version%3D1.0.0%26request%3DGetFeature%26typeName%3Dfifao%3AFAO_MAJOR%26CQL_FILTER%3Dfifao%3AF_AREA%3D21;Polygon2=http%3A%2F%2Fgeo.vliz.be%2Fgeoserver%2FMarbound%2Fows%3Fservice%3DWFS%26version%3D1.0.0%26request%3DGetFeature%26typeName%3DMarbound%3Aeez%26CQL_FILTER=INTERSECTS%28Marbound%3Athe_geom%2CPOLYGON%28%28-82.410003662+34.830001831%2C-42+34.830001831%2C-42+78.166666031%2C-82.410003662+78.166666031%2C-82.410003662+34.830001831%29%29%29
| + | |
| − | </nowiki>
| + | |
| − | | + | |
| − | | + | |
| − | ==== More information ====
| + | |
| − | | + | |
| − | This algorithm is the adaption to WPS-hadoop framework of the original IntersectionAlgorithm developed by 52North. This template was sent and discussed with FAO (Emmanuel Blondel) to be improved by the community according to their requirements (e.g. area of the intersections).
| + | |
| − | | + | |
| − | | + | |
| − | | + | |
| − | === TIFFUploader Algorithm ===
| + | |
| − | | + | |
| − | ==== Overview ====
| + | |
| | | | |
| − | Another algorithm was developed to create a visualization library that exploits a Geoserver WMS (Web Map Service) by uploading a file netCDF as a new Workspace and its bands as new layers.
| + | gCube Spatial Data Processing distinguishing features include: |
| | | | |
| − | ==== Class Diagram ====
| + | ; WPS-based access to an open and extensible set of processes |
| − | [[Image:TIFFUploaderAlgorithm.png|500px]]
| + | : all the processes hosted by the system are exposed via RESTful protocol enacting clients to be informed on the list of available processes (GetCapabilities), to get the specification of every process (DescribeProcess) and to execute a selected process (Execute); |
| | | | |
| − | ==== Geotiff Uploader library ====
| + | ; relying on a Hybrid and Distributed Computing Infrastructure; |
| | + | : every process can be designed to be executed on diverse and many 'computing nodes' (e.g. R engines, Java); |
| | | | |
| − | TiffUploader algorithm is based on [http://www.gdal.org/ GDAL native library] due to a software developed by Terradue called GeoTIFF Uploader, that uses a [http://gdal.org/java/ Java bind library] .
| + | ; easy integration of user-defined processes; |
| − | After downloaded a netCDF file on the local filesystem, Geotiff Uploader splits it in as many GeoTIFF files as the number of data bands. Finally the library upload these files as layers of a new Workspace just created from the netCDF file itself, on the Geoserver instance. The control returns to the WPSHadoop algorithm.
| + | : the system enact users to easily add their own algorithms to the set of those offered by the system, e.g. by [[Statistical Algorithms Importer]]; |
| | | | |
| − | '''Release note:''' since Geotiff Uploader is based on GDAL Java bind, it needs to be delivered with the right dependencies, according with the architecture that will run the application. For this purpose, multiple Maven profiles was created, each for the most popular architectures:
| + | ; rich array of ready to use processes; |
| | + | : the system is equipped with a [[Statistical Manager Algorithms | large set of ready to use algorithms]]; |
| | | | |
| − | * linux-i386
| + | ; open science support |
| − | * linux-x86_64
| + | : the system automatically provide for process repeatability and provenance by recording on the [[Workspace]] a comprehensive research object; |
| − | * mac-x86_64
| + | |
| | | | |
| | + | == Subsystems == |
| | | | |
| − | ==== TIFFUploaderAlgorithm.xml ====
| + | ;[[Statistical Manager|DataMiner / Statistical Manager]] |
| | + | : ... |
| | | | |
| − | <source lang="xml">
| + | ;[[Ecological Modeling]] |
| − | <?xml version="1.0" encoding="UTF-8"?>
| + | : ... |
| − | <wps:ProcessDescriptions xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
| + | |
| − | http://geoserver.itc.nl:8080/wps/schemas/wps/1.0.0/wpsDescribeProcess_response.xsd" xml:lang="en-US" service="WPS" version="1.0.0">
| + | |
| − | <ProcessDescription wps:processVersion="1.0.0" storeSupported="true" statusSupported="false">
| + | |
| − | <ows:Identifier>com.terradue.wps.ResamplerAlgorithm</ows:Identifier>
| + | |
| − | <ows:Title>TIFF Uploader Algorithm</ows:Title>
| + | |
| − | <ows:Abstract>by Hadoop</ows:Abstract>
| + | |
| − | <ows:Metadata xlink:title="TIFF Uploader " />
| + | |
| − | <DataInputs>
| + | |
| − | <Input minOccurs="1" maxOccurs="1">
| + | |
| − | <ows:Identifier>InputFile</ows:Identifier>
| + | |
| − | <ows:Title>Input FIle</ows:Title>
| + | |
| − | <ows:Abstract>Input file containg references to netCDF resources</ows:Abstract>
| + | |
| − | <LiteralData>
| + | |
| − | <ows:DataType ows:reference="xs:string"></ows:DataType>
| + | |
| − | <ows:AnyValue/>
| + | |
| − | </LiteralData>
| + | |
| − | </Input>
| + | |
| − | </DataInputs>
| + | |
| − | <ProcessOutputs>
| + | |
| − | <Output>
| + | |
| − | <ows:Identifier>result</ows:Identifier>
| + | |
| − | <ows:Title>result</ows:Title>
| + | |
| − | <ows:Abstract>result</ows:Abstract>
| + | |
| − | <LiteralOutput>
| + | |
| − | <ows:DataType ows:reference="xs:string"/>
| + | |
| − | </LiteralOutput>
| + | |
| − | </Output>
| + | |
| − | </ProcessOutputs>
| + | |
| − | </ProcessDescription>
| + | |
| − | </wps:ProcessDescriptions>
| + | |
| − | </source>
| + | |
| | | | |
| − | ==== Input/Output description ====
| + | ;[[Signal Processing]] |
| | + | : ... |
| | | | |
| − | The input for this WPSHadoop algorithm, called InputFile, is a file containing a list of URLs to netCDF files. These files are locally stored before to be splitted into as many new GeoTIFF files as the bands included in the input files.
| + | ; [[Geospatial Data Mining]] |
| − | Any line of the InputFile is processed by a separated instance of the mapper.
| + | : ... |
| − | At the end of all the processes, a GetCapabilities request is sent to the Geoserver instance and its answer is used as output (by reference) of the whole WPS process.
| + | |
gCube Spatial Data Processing offers a rich array of data analytics methods via OGC Web Processing Service (WPS).
Geospatial Data Processing takes advantage of the OGC Web Processing Service (WPS) as web interface.
It is implemented by relying on the gCube platform for data analytics.
