[ckan-dev] Work on the ckanext-datapreview plugin

Wed Jul 13 11:39:17 UTC 2011

On 13 July 2011 12:07, Aron Carroll <aron.carroll.lists at gmail.com> wrote:
> Hi all,
> I'm just posting a quick update on some work I'm doing on the data preview
> CKAN plugin (https://bitbucket.org/okfn/ckanext-datapreview).
> I've fixed a couple of minor issues with the plugin not handling failed
> requests to the data proxy API (as illustrated here
> http://thedatahub.org/package/fukushima-radiation-monitoring-greenpeace) as
> well as the formatting of the error messages. I've added these fixes in a
> separate fork of the project which can be found on Bitbucket,
> https://bitbucket.org/aron_/ckanext-datapreview.
> I'm now looking into implementing the ability to create graphs from CSV data
> and could do with some advice on various issues.
> 1. How to generate the graphs? It seems to me the best way to create useful
> graphs is to get users to generate them via a simple creation tool similar
> to the one on socrata.com.

I've not seen this, but rather than reinvent the wheel, why don't we
just use the Scraperwiki Views?

There is also plenty of learning from the ONS about drawing graphs,
such as choosing colours automatically to avoid problems with colour
blindness and printing on black/white printers. James Forrester has
the details - I'll ask him for those.

> 2. How to store the graphs? Can they be saved alongside the resource data in
> CKAN?

I'd have thought that the options that go into the graph creation
should go into either a new Resource View object, or a ResourceExtra
with key like view-1-options. I would have thought we just leave
browsers to generate the graph every time, rather than caching the
bitmap.

> 3. Where to find test data? Currently most of the CSV data is archived in
> zip or tar files and currently inaccessible so I'm having trouble finding
> useful data that can be actually be plotted on a graph. If anyone has any
> suggestions for test datasets I'd be extremely grateful.

Is there really no available tabular data on ckan.net?!

David

> So from here I'm going to try and add a widget to the data preview lightbox
> that creates a simple line graph from selected columns and move from there.
> If anyone has any suggestions for features that they'd like to see
> implemented I'd love to hear them.
> Cheers,
> Aron
>
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