[ka-Map-users] Controlling the number of points using addObjectGeo

[Paul Spencer]

Ok, then the event could be triggered as a result of the call to  
checkWrap and if any wrapping has occurred you would get an event  
indicating the new extents of the meta viewport.  You could then make  
your overlay image the size of the meta viewport (in pixels) and pin  
it to the top/left image in the meta viewport.  When this event is  
triggered, you would reposition the image and change its source so it  
would load a new overlay from the server.

Are you going to implement this and contribute?

Cheers

Paul

On 28-Feb-06, at 9:23 AM, Stephen Woodbridge wrote:

> Hi Paul,
>
> These get called for every tile load request if I understand your  
> description, if I pan diagonally then I would expect to get rows 
> +cols-1 (or more) events triggered as you add new rows and columns  
> to the meta_viewport.
>
> I think this a little too granular, but we might be able to roll up  
> these events. What I was thinking about was to consider the  
> additional tiles around the viewport as a meta_viewport that has  
> extents. Then when the viewport moves outside the meta_viewport a  
> single event is triggered and the new extents of the meta_viewport  
> are made available.
>
> If it is easy to get this from what you suggested below then that  
> would be great other you might consider add this type of event as I  
> think anyone trying to track an overlay with a server side image  
> will be able to use this.
>
> -Steve
>
> Paul Spencer wrote:
>> Steve,
>> I think that we should expose two events:
>> KAMAP_TILE_CHANGING
>> KAMAP_TILE_CHANGED
>> this would potentially allow the interface to expose the number  
>> of  tiles that are 'in the queue' and could be used for other  
>> purposes  to, like fixing overlays etc
>> KAMAP_TILE_CHANGING would be triggered in the setTile method of   
>> _layer (and affliates).
>> KAMAP_TILE_CHANGED would be triggered in the kaMap_imgOnLoad function
>> One thing to consider is that images do fail to load for various   
>> reasons and we need to be aware of the difference between an  
>> image  that is loaded the first time and an image that is loaded  
>> because of  an error, otherwise tile counts could be seriously  
>> impacted.
>> Would this meet your needs?
>> Cheers
>> Paul
>> On 28-Feb-06, at 7:58 AM, Stephen Woodbridge wrote:
>>> This is an excellent question as we have been doing something   
>>> similar with router overlays. We currently overlay an image just   
>>> the size of the viewport, but it would make sense to ask for a   
>>> larger image say the size of the preloaded tile extents and then   
>>> only update that when additional tiles are requested because the   
>>> preloaded tile extent needs to change because of panning or   
>>> zooming. Could this be made an ka-map event that can be easily  
>>> hooked?
>>>
>>> -Steve
>>>
>>> Base Bloc wrote:
>>>
>>>> Dear all,
>>>>  First off I would like to say that ka-map 0.2 is a fantastic   
>>>> piece of kit and thanks for all the work that people have put  
>>>> in  to this.
>>>>  I am currently building an application using 0.2 and I am  
>>>> using  the addObjectGeo function to add markers along with  
>>>> mouseover  events (pop-up windows) to the map. All is working as  
>>>> it should  and is looking good. My concern now is the number of  
>>>> markers; the  application is covering most of Southeast Asia and  
>>>> the number of  markers is going to be high. I am looking to use  
>>>> Ajax to connect  to a MySQL database to retrieve the point data  
>>>> relevant to the  area of the map being viewed, as if all of the  
>>>> points were to be  retrieved in one go it would result in a  
>>>> serious performance hit  for the user.
>>>>  I’m no ka-map expert, but I was wondering how ka-map does this   
>>>> efficiently with the tiles; as in it gets x number of tiles   
>>>> closest to the area being viewed then moves outwards, is there   
>>>> anyway to use the variable(s) that are being sent to the server  
>>>> to  request the tiles to also query the database and return the  
>>>> point  data in an equally efficient manor?
>>>>  Thanks in advance for your thoughts.
>>>>  Chris
>>>>   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>> Christopher Brown
>>>> Head of Internet Development
>>>> Base Bloc Cambodia
>>>> #33, 123, Phnom Penh, Cambodia.
>>>> P.O. Box 2086
>>>> www.basebloc.com
>>>> Tel (+885) 12 315 302
>>>>    
>>>> ------------------------------------------------------------------- 
>>>> -- ---
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>>>
>>>
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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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>

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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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