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Re: changing the level of detail depending on the level of zoom (or s cale)

From: Chris Lilley <chris@w3.org>
Date: Wed, 30 May 2001 00:36:04 +0200
Message-ID: <3B142454.82CC5C3C@w3.org>
To: Adam Van Den Hoven <Adam.Hoven@bluezone.net>
CC: "SVG Mailing List (E-mail)" <www-svg@w3.org>


Adam Van Den Hoven wrote:

> I came accross something that I'm not sure how to address, since I'm not
> sure that SVG has a declaritive mechanism for it. If I have a drawing of
> some sort (lets say a map of a community) that I've done with all sorts of
> detail. Is there any way to specify which parts of the drawing are available
> at different levels of zoom.

Yes, you can hook into zoom events. We probably need to be able to
control detail depending on which area has been zoomed, too.

> 
> Lets take my community drawing. If you are looking at the outer most level,
> then you are able to only see the outlines of the streets and lots, perhaps
> with indicators of which are sold and the price of the remaining. Then if
> you zoom into a street, you might see the lots, none of the sale
> information, the house outlines and the basic landscaping. if you zoom in
> more,  you see the layout of the sprinklers and the various beds. If you
> zoom into a house, you would get the layout of all the rooms with their
> descriptions. If you zoom futher in to a room you would get the layout of
> the furniture (or the appliances).

Yes. This turns out to be a fairly common requirement.

> The thing is that at the original view, I don't want the houses and the
> rooms muddying up the drawing.

I agree.

> Now I'll grant that this may not be a realistic example simply because the
> size of the actual drawing would be enormous.

Sure it is realistic - the trick is to use multiple SVG files and to
animate xlink:href attibutes on 'use' elements based on zoom events, to
cause higher detail or more simplified symbos to appear. Typically,
people will only zoon in on certain selected areas so you only need to
download the detail for those areas, not the entire map.

-- 
Chris
Received on Tuesday, 29 May 2001 18:36:11 GMT

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