Intercomparison tools. The WPS__________________
This task addresses the issue of collocating datasets, that is finding matches of observations in space and time. To be able to compare the values and establish and compare the quality of the measured data it is necessary to get the data products in a comparable state. The collocated measurements can be used to estimate uncertainty in the dataset with unknown quality, based on the reference data, which itself might be subject to uncertainties.The intercomparison tools can produce outputs of the differences and associated quality estimates either at specific spatial locations or over a grid of defined resolution The systems developed are based on extending the EC funded INTAMAP (project for spatial interpolation and methodologies / tools from the ESA) and GECA (project for collocation and intercomparison) services consisting of providing collocation and inter-comparison as a Web Processing Service (WPS) within GEOSS. A case study based on air quality measurement from both remote and in-situ sensors has been used to inform the design of the solution and test the results.
GECAaaS WPS (S&T)
One of the most innovative functionalities integrated in the GEOSS portal is the capability to assess quality using reference data. To illustrate the methodology, a web form or “Data Intercomparison“ allow for selecting a satellite image and a collection of in-situ data that are send to the GECA Toolset (a toolkit for ingesting, processing and inter-comparing satellite data against correlative data) as a request to an online web processing service (a WPS). The intercomparison result is shown either within the GEOSS Portal or in a pop-up window. If accepted by the user, the results can be transformed into a quality indicator as explained below.
Figure 1: GECA as a service integrated in the GEOSS Portal