Support #3818

RO: While testing compliant WMS serving multiple layers, linkage checker is wrongly reporting that the identifiers of the layers should be the same as the identifier of the metadata file of the data set (this not being correct according to TG)

Added by Maxim Iurie 6 months ago. Updated 6 months ago.

Status:NewStart date:31 Jan 2020
Priority:HighDue date:
Assignee:-% Done:

0%

Category:Linkage Checker
Target version:-
Submitting Organisation:Essensys Software Knowledge-Base relevant?:Yes
Proactive:Yes Keyword #1:WMS
Country:RO - Romania Keyword #2:
Originating UI: Keyword #3:

Description

We assume that there is an issue with the testing of WMS services that are serving multiple layers of the same dataset or multiple layers from different datasets.

We are reporting this issue based on the text of the disclaimer present in the linkage checker (https://inspire-geoportal.ec.europa.eu/linkagechecker.html) as there are inconsistencies between the checks performed by the INSPIRE Geoportal and the Reference Validator,

We seek guidance if the issue is not in the linkage checker validator or a confirmation that there is an issue in the linkage checker validator.

How to test:

Link to data set metdata: https://inspire.meteoromania.ro/WIGOS/MD-DS

Link to view service metdata: https://inspire.meteoromania.ro/WIGOS/MD-WMS

Link to download service metdata: https://inspire.meteoromania.ro/WIGOS/MD-WFS

 

The result of the test can be found here:

https://inspire-geoportal.ec.europa.eu/resources/sandbox/INSPIRE-7f24b017-4429-11ea-8318-0050563f01ec_20200131-135920/

Interoperability is reported 75% compliant for the view service (WMS) as can be seen here:

https://inspire-geoportal.ec.europa.eu/resources/sandbox/INSPIRE-7f24b017-4429-11ea-8318-0050563f01ec_20200131-135920/view/services/1/resourceReport/

For the two layers served via WMS, the linkage checker validator is reporting the following interoperability issues:

For layer 'EF.EnvironmentalMonitoringFacilities' one or more of the layer Unique Resource Identifier(s) specified in wms:Authority and wms:Identifier ' Identifier: "ddf93f53-5975-46c6-946c-1cc8da488e22", Authority name: "RO.ANM" -> "https://inspire.meteoromania.ro/"', could not be found among the Coupled Resources retrieved after dereferencing the information specified in wms:MetadataURL 'Namespace: "https://inspire.meteoromania.ro/"" Code: "WIGOS/MD-DS"'

For layer 'EF.EnvironmentalMonitoringNetworks' one or more of the layer Unique Resource Identifier(s) specified in wms:Authority and wms:Identifier ' Identifier: "bfc1fb2c-d12f-4684-8ab4-ccae80585dc2", Authority name: "RO.ANM" -> "https://inspire.meteoromania.ro/"', could not be found among the Coupled Resources retrieved after dereferencing the information specified in wms:MetadataURL 'Namespace: "https://inspire.meteoromania.ro/"" Code: "WIGOS/MD-DS"'

As the code ”WIGOS/MD-DS” is the code of the metadata file of the dataset (MD - Metadata, DS - Data set, WIGOS - the acronim of the dataset), it means that the text of the errors above are indicating that the identifier of each layer should be the same as the identifier of the metadata file of the dataset.

It is neither correct that the identifier of the layer to be the same as the identifier of the metadata file of the dataset, neither that both layers to have the same identifier.

In order not to receive these errors in the Linkage checker we should provide the same value ”WIGOS/MD-DS” instead of the unique GUIDs in the GetCapabilities document. In this way the linkage checker will not report an error as we tested when we reported issue #3816.

But if we would provide the same identifier for both layers, this would be against the ETF for layer Authority URL (https://github.com/inspire-eu-validation/view-service/blob/review-ats-tg_3.11/iso-19128/at38-getcapabilities-layer-authority-url.md) that checks ”that the Identifier element is unique for its authority” for each Identifier element. Subsequently the official validator will return an error while performing the test for ”Conformance Class: View Service – WMS” at the test ”a38-getcapabilities-layer-authority-url” indicating that there are non-unique identifiers present. Also at the page 37 of the TG for the implementation of INSPIRE View Services, version 3.11 (https://inspire.ec.europa.eu/documents/technical-guidance-implementation-inspire-view-services-1) it can be seen in the example that each layer has its own identifier that is a unique GUID.

Therefore, our understanding is that the ETF is correct, the ”Conformance Class: View Service – WMS” test is correct, but the errors provided by the Linkage checker are incorrect.

Same error is reported also for other valid WMS services that we tested. For example the same behavior can be observed for the datasets from Malta.

Links to test:

Link to data set metdata: https://msdi.data.gov.mt/geonetwork/srv/eng/csw?service=CSW&request=GetRecordById&version=2.0.2&outputSchema=http://www.isotc211.org/2005/gmd&elementSetName=full&id=4cc79d52-f58e-4a95-ba42-a8e8426b22d2

Link to view service metdata: https://msdi.data.gov.mt/geonetwork/srv/eng/csw?service=CSW&request=GetRecordById&version=2.0.2&outputSchema=http://www.isotc211.org/2005/gmd&elementSetName=full&id=37569840-7c18-49da-bac5-f730491591e4

Link to download service metdata: https://msdi.data.gov.mt/geonetwork/srv/eng/csw?service=CSW&request=GetRecordById&version=2.0.2&outputSchema=http://www.isotc211.org/2005/gmd&elementSetName=full&id=4394b124-6cd1-46d4-bd86-53ecd15a82f5

Results of this test can be seen here: https://inspire-geoportal.ec.europa.eu/resources/sandbox/INSPIRE-bd6944f6-41da-11ea-8318-0050563f01ec_20200128-153032/

As Malta is using the same WMS endpoint for all datasets, the linkage checker is triggering incorrect errors, indicating that the identifer of the metadata file of the dataset should be the same as the identifier of the layer.

Hope this will help to find the issue in the Linkage Checker in relation to WMS services that are serving multiple layers of one or more datasets. If the source code of the Linkage checker is available, please share it as we can also look to spot the error.

If there is a real problem with the GetCapabilities document of the WMS view service and if the errors are triggered correctly by the linkage checker, than please let us know.

In order to link each layer to its dataset, the following element exist in the Getcapabilities document:

<MetadataURL type="19139">
<Format>application/xml</Format>
<OnlineResource xlink:type="simple" xlink:href="https://inspire.meteoromania.ro/WIGOS/MD-DS"/>
</MetadataURL>

Therefore it is neither corect to test for each layer of the view service that the identifier of the layer is the same as the identifier of the metadata of the dataset

<Identifier authority="RO.ANM">WIGOS/MD-DS</Identifier>

instead of having unique identifiers for each layer

<Identifier authority="RO.ANM">ddf93f53-5975-46c6-946c-1cc8da488e22</Identifier>

while also the information would be redundant.

 

Best regards,

Iurie Maxim

History

#1 Updated by Maxim Iurie 6 months ago

The above links were changed:

 

Instead of:

 

Link to data set metdata according to version 2.0 of the TG: https://inspire.meteoromania.ro/WIGOS/MD-DS

Link to view service metdata according to version 2.0 of the TG: https://inspire.meteoromania.ro/WIGOS/MD-WMS

Link to download service metdata according to version 2.0 of the TG: https://inspire.meteoromania.ro/WIGOS/MD-WFS

 

should be used now:

 

Link to data set metdata according to version 1.3 of the TG: https://geoportal.meteoromania.ro/WIGOS/MD-DS

Link to view service metdata according to version 1.3 of the TG: https://geoportal.meteoromania.ro/WIGOS/MD-WMS

Link to download service metdata according to version 1.3 of the TG: https://geoportal.meteoromania.ro/WIGOS/MD-WFS

 

We are waiting for a feedback in order to understand if the linckage checker has an issue or if we should change something within the implementation.

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