[ka-Map-users] Same API, but map images instead of tiles

[Paul Spencer]

I have no idea whether it would be better to create tiles of vectors  
or render the vectors directly.  If it was SVG then I think rendering  
vectors in the client would be best.

If you are planning to use wz_jsgraphics, I think you will find the  
performance limiting, and its probably the best js graphics  
library ... or at least, the best I have found ...

I'm not sure how Goggle does it ... I think in IE they use VRML  
actually ...

Sparse tiles (i.e. transparent images of vectors) are really quite  
small to download to the client and you get tons of benefits, so you  
may find you are doing a lot of work for no benefit

Cheers

Paul

On 19-Sep-05, at 6:11 PM, Steve Lime wrote:

> Hi Joe: Javascript is ton's of fun- really. It just sucks to debug  
> some times...
>
> I haven't looked at Paul's code but I imagine it would be possible  
> to extend the geo object class just a bit to make it possible to  
> have (if not already there):
>
>   - relative coordinates (relative to the viewport)
>   - dynamic (ka-map aware) URLs
>   - visibility? (so you could control via a legend)
>
> In theory you could have many geo objects at the same point all  
> drawing content from multiple places and each kept up-to-date via  
> ka-map.
>
> That said, you're treading very close to the point where ka-map may  
> not be the best interface choice. The UI is so responsive it is  
> really tempting as a user to make a zillion small tweaks to the  
> viewport. With much non-tiled content you loose the exact reason  
> you chose ka-map in the first place.
>
> Steve
>
>
>>>> Joe Franklin <traderboy at yahoo.com> 09/19/05 2:32 PM >>>
>>>>
> That's what I'm trying to do.  I want to be able to
> display/hide vector layers listed in the legend
> without creating all the tiles for the vectors.  I
> created a drawing canvas that retrieves the
> vector-only layers whenever the map extent is changed.
>  The advantage I see is that I only have to create
> tiles for my raster background.  I can then draw all
> the vector layers separately and return them in one
> gif/png.  Plus I can get images from a WMS as well.
> It looks like it can be done without adding too much
> code (javascript is not a lot of fun!)  Does this make
> sense to separate the raster and vector layers?
>
> Steve (hmm, lots of steves in this group)
>
>
>>> I wonder if you couldn't just take advantage of
>>>
> ka-map's feature drawing
>
>>> ability (it has that right?). That is, tie a URL
>>>
> (more precisely a URL template)
>
>>> to the center of the view port (image coords) and
>>>
> that URL generates a
>
>>> map the same size as the viewport. You could have a
>>>
> template model that
>
>>> would allow access to the viewport size and current
>>>
> extent.
>
>>>
>>>  e.g.
>>>
> http://someserver.somplace/cgi-bin/mapserver?...&extent=ka-map- 
> extent&mapsize=ka-map-width+ka-map-height
>
>>>
>>> If you could  control a features z-index then you
>>>
> could use this to place
>
>>> background or foreground maps. This would be kinda
>>>
> like MapServer's
>
>>> inline layers. Wouldn't impact the tiling at all...
>>>
>>> Steve
>>>
>
>
>
>
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|Paul Spencer                           pspencer at dmsolutions.ca   |
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|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|
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