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CKAN and its Spatial Extensions Review

Contents

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Overview

In this review, we provide our investigation findings on CKAN and its two Spatial related extensions namely Geospatial extenstion and Remote harvesting extension.

Take note that most of our investigation findings are focused on two particular Geospatial extension for CKAN's plugins namely CSW Server (cswserver) and CSW Harvester (csw_harvester). These findings may not be relevant if the versions you installed are different from the ones we used.

Software Versions

  • ckanext-spatial - 2.0
  • ckanext-harvest - 2.0

Demonstration service links

We investigated CKAN and its Spatial extensions by installing them in a single virtual machine running on NeCTAR research cloud.

The CKAN demo instance we created is solely for evaluation purposes. We can't guarantee its availability and most importantly you shouldn't be using our CKAN demo instance to create and store your datasets.

The following are a number of useful links to our CKAN demo instance:

Note: For those who want to try out CKAN functionality that requires sysadmin user access, please contact us on cg-admin@csiro.au.

1. Our CKAN demo instance on NeCTAR research cloud:

2. Our CKAN Harvest and Users web interface:

3. Our CKAN CSW Service Endpoints:

Investigation Findings

The following list provides summary of our investigation findings:
  • Installation process is tedious and a bit involved - in particular on setting up Spatial Extensions.
  • Once a harvest source is removed, the same harvest source cannot be re-created without manually deleting related records in the database.
  • Compatibility issue - we can't get the latest CKAN i.e. 2.1 (at the time of evaluation) to work with the latest or stable version of CKAN's Spatial Extensions. At the time of evaluation, only CKAN 2.0 work with release 2.0 of CKAN Spatial Extensions.
  • There are issues with release 2.0 of ckanext-harvest extension. Those issues are documented in the Troubleshooting section of CKANHarvestingGuide.
  • Certain CKAN's Geospatial Extension's plugins such as CSW Server is still evolving. The one we evaluated i.e. cswserver plugin currently supported only 3 methods namely GetCapabilities, GetRecords and GetRecordById. At the time of evaluating, a new plugin called ckan-pycsw has emerged and will eventually replace the one we evaluated. According to ckan-pycsw official website, this plugin is powered by pycsw which fully implements the OGC CSW specification.
  • Currently, only datasets that are harvested with CKAN's Spatial Harvesters can be served by CKAN's CSW Server (see this link for further details).

Conclusions

To conclude, we've reviewed CKAN and its two Geospatial extension plugins namely CSW Server and CSW Harvester. From our expereince, CKAN itself seems to be intuitive, extensible and loaded with many out of the box ready to use features. It is a general purpose data registry. Apart from few issues mentioned in CKANHarvestingGuide, its CSW harvesting function seems to be working. As for the CSW Server, the one (release 2.0) we tried doesn't fully implement OGC CSW specification. Having said that, we managed to harvest the harvested metadata from CKAN into a GeoNetwork instance. Last but not least, considering a number of issues discovered on release 2.0 of ckanext-harvest extension and also the CKAN Geospatial community is deprecating CSW Server plugin and replacing it with a more mature one i.e. ckan-pycsw, we don't recommend those two plugins (CSW Server and CSW Harvester) use in production environment unless those issues have been addressed in their latest stable releases.

 
Topic revision: r7 - 10 Feb 2014, RichardGoh
 

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