[ka-Map-users] Number of tiles displayed

[Jorden Dunne]

Thanks Paul,

I had made the images 300 x 200 on a map that is 600 x 500 and I am
displaying one layer - the base. However it seems to be trying to pull
180 images when the map is loading. Here are the values that the
variables are set to in config.php; 

$tileWidth = 300;
$tileHeight =200;
$metaWidth = 3;
$metaHeight = 3;
$metaBuffer = 40;

The tiles are also being created as GIF's. 

The same index.html file is being used to serve both a full screen
instance of kaMap and the 600 x 500 map, based on request parameters the
size of the map is altered in startup.js. Would this have an influence
on the amount of images being requested?

Thanks,
Jorden

-----Original Message-----
From: Paul Spencer [mailto:pspencer at dmsolutions.ca] 
Sent: 01 August 2006 15:18
To: Jorden Dunne
Cc: ka-map-users at lists.maptools.org
Subject: Re: [ka-Map-users] Number of tiles displayed

Jorden,

the number of tiles that are initially loaded depend on:

1) size of map in the page and tile size.  If your map is 600 x 400  
and your tile size is 200 x 200, you need a minimum of 3x2 = 6 tiles  
to fill the map.  ka-Map also adds tiles around the edge to ensure  
that as the user drags, there's something to fill in with.  This  
would typically add 3 more tiles in each direction so you end up with  
6 x 5 = 30 tiles.  A 'full page' map can easily end up requesting 80  
tiles ...

2) number of discrete layers in the client (GROUPS on the server  
side).  For each one that is ON, multiple by the number above.

3) depending on the version of ka-Map you are using, it may load  
tiles for layers that are not ON

4) size of individual tiles depends on the output format you have  
chosen.  If you are using PNG24 or JPEG with a low compression, you  
will have 20-40kb tiles.  GIF and 8bit PNG (and high compression  
JPEG) will end up in the 8-20kb range.

If you only have one layer and a large map, try starting the users  
off with a small map size and giving them a control to dynamically  
make it larger if they want to take the performance hit.

If you have multiple layers and they are all on by default, try  
turning the extra layers off for the first load to prevent the extra  
tiles on initial page load and allow the users to turn them on as  
required.

Cheers

Paul

On 1-Aug-06, at 9:44 AM, Jorden Dunne wrote:

> Hi,
>
>
>
> Is there a way to specify the amount of tiles that will be  
> generated when the user loads kaMap. A lot of our users may still  
> be using dial-up and sometimes our map tries to load about 80  
> images/tiles. I had a look at tile.php but can't seem to see where  
> this can be changed.
>
>
>
> Thanks,
>
> Jorden
>
>
>
> __________________________________________
>
>
>
> Jorden Dunne
>
> IT / MIS
>
>
>
> Irish Broadband
>
> Unit 6B
>
> Sandyford Business Centre
>
> Sandyford Industrial Estate
>
> Dublin 18
>
>
>
> tel:          (01) 481 1495
>
> email:     jorden.dunne at irishbroadband.ie
>
>
>
>
>
> _______________________________________________
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> ka-Map-users at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/ka-map-users

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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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