[ckan-discuss] CKAN and INSPIRE

[John Bywater]

Hi all,

Friedrich Lindenberg wrote:
> Hi all, 
> 
> On Dec 7, 2010, at 7:41 PM, Stefano Costa wrote:
>> inspired by the availability of a fair amount of geodata on the
>> http://dati.piemonte.it/ portal, I would like to ask for an update about
>> CKAN and INSPIRE.
> 
> Let me quote from a summary that John gave on this a few days ago: 
> 
> quote >>
> 
> Certainly can put together a summary of CKAN's capabilities in relation to the INSPIRE directive. ...The standout features are:
> 
> 1. collect remotely authored GEMINI 2 metadata records;
> 
> 2. search collected GEMINI 2 metadata records by GEMINI element;
> 
> 3. present collected GEMINI 2 metadata records to EU.
> 
> << quote
> 

Thanks for that! ;-)


> My understanding of this is that we can: 
> 
> a) Store the general metadata required by INSPIRE as interprested by the UK location programme.

Yes, that works already.


> b) Harvest the data from CSW sources 

Yes, that works already, also from WAF sources (effectively any HTML 
document containing relative links to GEMINI 2 documents), and from 
single documents.


> c) soon: pipe it into a GeoNetworks server that will expose a CSW interface for others to harvest. 
> 

We're planning to implement a simple CSW interface to support this.

So that's not working at the moment.


> I'm not sure if we can do any of the following at the moment (I'm putting these out more as questions to John): 
> 

The other main thing is that there's very good support for reading the 
values of the GEMINI 2 elements from a collected GEMINI 2 document.

That's used to write CKAN Packages, so that the "extras" dictionary of a 
CKAN package that has been written from a collected GEMINI 2 document 
will contain the GEMINI 2 document elements, as named values.

I should also mention that changes to collected GEMINI 2 documents will 
result in packages being updated (not duplicated).


> a) Display data packages on an OSM/GM map

As part of the UK Location Programme, an open source map widget is being 
developed, which will be used on a page of the Drupal front end of 
data.gov.uk to support searching for datasets within a spatial extent.

Of course, there might be other technical solutions to consider. The map 
widget provider is a value competitor of Google, and some CKAN users may 
prefer to patronise Google's map services instead.

Whilst we're thinking about maps, another part of INSPIRE is about Web 
Mapping Service (WMS). Another open source widget is being developed to 
do allow a selection of the results of searching for spatial datasets 
(maps, remember) to be previewed together as semi-transparent overlays.

At the moment, as far as I know, there is no plan or proposal to develop 
CKAN's Web API to integrate these widgets. Somebody could propose this?


Caveat: There might only be one widget that does both jobs. :-)


> b) Search for packages by region with gazeteering (?) support (i.e. search traffic in:berlin)

That's not supported at the moment. There's also no plan or proposal to 
support this. Apparently, it's a tricky thing to do well. Hence the map 
widget to describe the bounding box.

It's possible to put named extents in a GEMINI 2 document, but they will 
be an independent search facet. That is, essentially keyword matching: 
it won't involve the bounding box information in the GEMINI 2 document.

We could consider using a gazeteer to get a bounding box for a named 
extent, but the UK Location Programme has decided not to do this (at 
least for now). Given a bounding box can be constructed on the map 
widget, and given that common names of places are (unsurprisingly) 
highly vernacular and correspond only to a small extent with official 
names and extents, the estimated benefit for the estimated cost was 
thought to be too low.

Apparently, not even the UK's emergency services have solved this very 
real problem satisfactorily.

But that's not to say it wouldn't be useful for people who are familiar 
with the extents and limitation of the particular gazetteer in use on a 
given site. It could be user-specific, so you can pick the gazetteer you 
know and love? It doesn't sound a bit unlikely, doesn't it. :-)


> c) Expose data as CSW or one of the other OGC services internally
> 

There's a plan to add a minimal CSW service interface to CKAN at the 
beginning of next year.


>> There is a ckanext module done by Jo Walsh
>> http://www.knowledgeforge.net/ckan/ckanext/file/tip/ckanext/geo/geo_form.py and a wiki page http://wiki.okfn.org/ckan/inspire that is filled with lots of details but little introduction.
>>
>> To put it shortly, I'd like to make http://it.ckan.net/ INSPIRE-ready
>> (we have a few people willing to contribute) and see what can be done in
>> terms of catalog geo-visualization (as an external service probably?).

Wow! Let's try to have a discussion about this?


> 
> I would like to add on to that: having the ability to support INSPIRE functionality in community catalogues would be a killer feature, I think here in Germany we could have a lot of impact with this. 
> 

Very encouraging. Let's also discuss this. :-)

Best wishes,

John.

> Friedrich 
> 
>> Thanks,
>> steko
>>