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Re: Orphaned annotations

From: Marja-Riitta Koivunen <marja@w3.org>
Date: Mon, 18 Mar 2002 09:02:07 -0500
Message-Id: <>
To: Nick Kew <nick@webthing.com>, <www-annotation@w3.org>
At 01:37 AM 3/18/2002 +0000, Nick Kew wrote:

>I've done a little more work on a client for Annotea, with a view to
>supporting annotations in Page Valet.
>Since Page Valet generates a normalised representation of page markup
>showing validation errors and accessibility warnings as and when they
>arise in the markup, it makes sense to use annotea's pseudo-xpointers[1]
>(which valet already uses) to reference annotations to the markup.
>This is essentially equivalent to what any other annotea client can do,
>but because Valet is a diagnostic tool, the view and its purpose differ.
>As soon as I had a working prototype, it became abundantly clear that
>there is a deep and fundamental flaw in Annotea: we construct long
>and detailed pseudo-xpointers, but these become totally useless as
>soon as a page is updated.  And annotea has no mechanism for dealing
>with this, nor indeed even to detect that a page has changed.

First, the amount of problems depends on what kinds of changes are made to 
the page and how well id's are used. Sometimes updates can cause only minor 
problems e.g. many reviewing changes are often local and the annotation 
stays pretty much in the right area even after changing the document (I use 
annotations myself all the time now for creating comments and reading them 
in context while changing the page and I haven't had problems yet).

But you are right, there is a lot of research that has been done and can be 
done in this area. While we have been thinking of different ways of 
detecting the changes in the document or even that the information that the 
document has changed and looking some of the research on robust pointers we 
have not had resources yet to concentrate on this problem.

So I'm very happy that you are doing that with other EARL people. Annotea 
does not prevent the use of additional mechanisms that will make the 
pointers more robust. New information can be added to schemas for instance 
about the document version CVS or ETAG or a checksum. And the clients can 
be taught to understand that info when available.

Second, how to change the status of annotations either manually or 
automatically as part of the review process is an interesting problem and 
we have been discussing about couple of approaches (in our future to do 
list). If there are use cases, ideas, solutions etc. we are interested in 
hearing about them.

Received on Monday, 18 March 2002 09:05:50 UTC

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