Availability of the OGC geoprocessing standard: March 2011 reality check

López-Pellicer, Francisco J.; Rentería-Agualimpia, Walter; Béjar, Rubén; Muro‐Medrano, Pedro R.; Zarazaga‐Soria, F. Javier

doi:10.1016/j.cageo.2011.10.023

Cited by 20 publications

(7 citation statements)

References 17 publications

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“…A task like service discovery is not strongly supported with syntactic interface descriptions, as different operations can have the same input elements or similar operations can have different inputs and outputs [12]. The generic nature of descriptions of OGC WPS has been criticised, as users and also software clients have difficulties understanding the requirements of input data and interpreting the service output [35,36].…”

Section: Extended Operation Descriptionsmentioning

confidence: 99%

Coupling Knowledge with GIS Operations: The Benefits of Extended Operation Descriptions

Hofer

Papadakis

Mäs

2017

IJGI

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Abstract:The automated development of spatial analysis workflows is one of the envisioned benefits of Web services that provide geoprocessing functionality. Automated workflow development requires the means to translate a user objective into a series of geographic information system (GIS) operations and to evaluate the match between data and operations. Even though full automation is yet out of reach, users benefit from formalized knowledge about operations that is available during workflow development. This article presents user support during workflow development based on a recent approach to extended operation descriptions. User support thereby focuses on the discovery of operations across GIS tools and the validation of chains of spatial analysis operations. The required knowledge about operations is stored in a knowledge base, which builds on an approach called geooperators and extends the geooperator approach with a data-type ontology for describing the interfaces of geooperators and for expressing constraints of geooperator inputs. The advantages of the knowledge base are demonstrated for the construction of a multi-criteria decision making workflow. This workflow contains a set of pre-processing tasks for the input datasets and eventually the calculation of a cost distance raster. A critical discussion of the complexity of the knowledge base and a comparison with existing approaches complement this contribution.

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Section: Extended Operation Descriptionsmentioning

confidence: 99%

Coupling Knowledge with GIS Operations: The Benefits of Extended Operation Descriptions

Hofer

Papadakis

Mäs

2017

IJGI

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“…With a series of seed URLs and a given topic, focused crawlers aim to continually crawl as many webpages relevant to the given topic and keep the amount of irrelevant webpages crawled to the minimum [41]. For example, Lopez-Pellicer et al [26,45] developed a focused crawler for geospatial web services. This crawler utilized Bing, Google and Yahoo!…”

Section: Surface Geospatial Web Services Discoverymentioning

confidence: 99%

Discovering Land Cover Web Map Services from the Deep Web with JavaScript Invocation Rules

Hou

Chen

2016

IJGI

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Automatic discovery of isolated land cover web map services (LCWMSs) can potentially help in sharing land cover data. Currently, various search engine-based and crawler-based approaches have been developed for finding services dispersed throughout the surface web. In fact, with the prevalence of geospatial web applications, a considerable number of LCWMSs are hidden in JavaScript code, which belongs to the deep web. However, discovering LCWMSs from JavaScript code remains an open challenge. This paper aims to solve this challenge by proposing a focused deep web crawler for finding more LCWMSs from deep web JavaScript code and the surface web. First, the names of a group of JavaScript links are abstracted as initial judgements. Through name matching, these judgements are utilized to judge whether or not the fetched webpages contain predefined JavaScript links that may prompt JavaScript code to invoke WMSs. Secondly, some JavaScript invocation functions and URL formats for WMS are summarized as JavaScript invocation rules from prior knowledge of how WMSs are employed and coded in JavaScript. These invocation rules are used to identify the JavaScript code for extracting candidate WMSs through rule matching. The above two operations are incorporated into a traditional focused crawling strategy situated between the tasks of fetching webpages and parsing webpages. Thirdly, LCWMSs are selected by matching services with a set of land cover keywords. Moreover, a search engine for LCWMSs is implemented that uses the focused deep web crawler to retrieve and integrate the LCWMSs it discovers. In the first experiment, eight online geospatial web applications serve as seed URLs (Uniform Resource Locators) and crawling scopes; the proposed crawler addresses only the JavaScript code in these eight applications. All 32 available WMSs hidden in JavaScript code were found using the proposed crawler, while not one WMS was discovered through the focused crawler-based approach. This result shows that the proposed crawler has the ability to discover WMSs hidden in JavaScript code. The second experiment uses 4842 seed URLs updated daily. The crawler found a total of 17,874 available WMSs, of which 11,901 were LCWMSs. Our approach discovered a greater number of services than those found using previous approaches. It indicates that the proposed crawler has a large advantage in discovering LCWMSs from the surface web and from JavaScript code. Furthermore, a simple case study demonstrates that the designed LCWMS search engine represents an important step towards realizing land cover information integration for global mapping and monitoring purposes.

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“…Data providing services such as web maps, feature, and coverage services are well established, whereas only a small fraction of web services provide geoprocessing functionalities (LOPEZ-PELLICER et al 2012). Nevertheless, a series of examples demonstrates the use of web processing services (WPS), the OGC standard for providing online geoprocessing.…”

Section: Introductionmentioning

confidence: 99%

Common Elements in Semantic Descriptions of Web Processing Services

Hofer¹

2015

giforum

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Web Processing Services (WPS) offer geoprocessing functionalities online. The description of an offered process to date consists of a textual description of the operation, and a specification of input and output parameters. This description is limited in detail and makes search, discovery, and composition of services difficult. Two approaches have been proposed to extend these service descriptions: ontology-based descriptions and WPS profiles, with differing complexity and intended use. This contribution confronts the two approaches, and suggests structured metadata as a linkage between service profiles and ontologies as future work.

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Availability of the OGC geoprocessing standard: March 2011 reality check

Cited by 20 publications

References 17 publications

Coupling Knowledge with GIS Operations: The Benefits of Extended Operation Descriptions

Coupling Knowledge with GIS Operations: The Benefits of Extended Operation Descriptions

Discovering Land Cover Web Map Services from the Deep Web with JavaScript Invocation Rules

Common Elements in Semantic Descriptions of Web Processing Services

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