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

Steve Lime steve.lime at dnr.state.mn.us
Mon Sep 19 14:44:08 EDT 2005

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...


>>> David Bitner <osgis.lists at gmail.com> 09/19/05 1:07 PM >>>
Frankly, I have one use for which what Steve W's approach would be genius. 
If you could have all your static layers which are going to be cached once 
and rarely if ever change, then for folks who have layers that are time 
specific or are changing day to day, then just drawing those for the screen 
without any kind of cacheing would be great. 

The behaviour to the end user would be transparent since ka-map hides all 
but the base layers during dragging so if we had a mouseup event that fired 
off a request just for the one dynamic layer (think weather, vehicle 
locations, flight tracks ...) you would get the instant feedback that makes 
ka-map wonderful without being limited to datasets that play well with that 
type of interface.


On 9/19/05, Steve Lime <steve.lime at dnr.state.mn.us> wrote:
> I can see the rationale but there are many other interfaces that give you 
> this in one way or another now so is it worth bothering with? Seems to me 
> that ka-map has a pretty well-defined niche carved out and it should stick 
> to it, as opposed to making it do everything ROSA/jbox/mapbender/... already 
> do.
> Steve
> >>> Stephen Woodbridge <woodbri at swoodbridge.com> 09/18/05 1:50 PM >>>
> Hi Paul,
> I really like a lot of what is happening with ka-map. It is great to see 
> all the community effort going into ka-map.
> I was wondering what it would take to make it work without tiles as an
> option. The idea would be that most of the code and logic would be the
> same but instead of pulling tiles it would just request a single image. 
> On a pan the current image would slide like the current code and a new
> image would be requested and replace the partially obstructed image from
> the pan operation when it is ready. I was thinking that this part (ie: 
> tile vs map image rendering) could be broken into two separate models
> with a common API and then depending on which was used you would get
> different rendering behavior.
> Why would anyone want this?
> 1) less server requests
> 2) no need for tiles and managing the tiles and disk space
> 3) maintains the rich no page refresh UI
> 4) would allow richer server side image manipulation than exists today
> because of the need to generate generic tiles. 
> 5) separates application development from deploy concerns and issues
> 6) would allow ka-map to do something that google can not do
> Anyway, I thought I would float the idea and see what you had to say.
> Also I'm interested if others on the list think there would be value for 
> something like this.
> -Steve W.
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