[ka-Map-users] blank map

Paul Spencer pspencer at dmsolutions.ca
Wed Jul 20 17:38:46 EDT 2005


you can create a custom javascript class that performs the same function 
as the _layer class (say _myLayer) in kaMap.js and override the 
behaviour of the setTile function to accomplish something like this. 
The new setTile would pass the time parameters to the tile.php script.

You will need a customized version of init.php to create your custom 
layer objects based on your needs, so if you mark a layer or group as 
time-sensitive in some way, then when init.php is creating the 
javascript to add new layers to a _map object, you can use _myLayer 
instead of _layer and it will use your custom setTile to initialize tiles.

You will need a customized version of tile.php to accept time parameters 
on the URL and do something specific like set metadata or do variable 
replacement in the map file.

You will probably want to extend the caching to add an additional layer 
of directories to include the timestamp OR always force drawing of 
time-sensitive layers.  If you use single points in time, you may be 
able to cache them, if you use arbitrary ranges then I would suspect it 
would be better to not cache them (with the associated drop in 
performance of course).



David Bitner wrote:
> Alright Paul,
> Thanks for you help today.  Looking at the maps I'm getting now make
> me think that you're right about the tiling of the small layers --
> especially once the tiles have been pregenerated.
> My next question is about adding layers that require a filter that
> will be filled with other html inputs such as grab me all the data
> between these two times.  The filter I use in my apps now is done by
> either recreating the DATA statement in mapscript or by using variable
> substitution with CGI mapscript.  Now you could just send the
> starttime and endtime with every layer, but this is going to cause big
> problems with cacheing.  Do you see any possiblities for an approach
> that could accomodate this?
> On 7/20/05, Paul Spencer <pspencer at dmsolutions.ca> wrote:
>>I think there are two problems.
>>First, ka-Map treats all 'group' layers as additional overlays and turns
>>them off temporarily during dragging to provide better responsiveness in
>>the UI.  The group that is 'always on' is the '__base__' group ... all
>>layers that don't have a group are automagically put in this group.
>>Second, there seems to be a bug in ka-Map that it is not turning the
>>layers back on after dragging.  I will look into that part.
>>Also note that you can add opacity to your overlay layers by putting
>>"opacity" "50" into the metadata of the first layer in any group and
>>that opacity will be used on the div  that contains that group of layers
>>... I add this just as a side note for everyone.
>>David Bitner wrote:
>>>I'm trying to get kamap from CVS yesterday up and running.
>>>The problem that I am having is that when I load the page, I get the
>>>tiles to show up just fine -- but then when I pan, either nothing
>>>shows up until I turn layers off and on again or the map pans with no
>>>animation.  (http://maps.macnoise.com/ka-map/htdocs/) Running the
>>>javascript console on firefox (problem happens in both ie and firefox)
>>>shows no errors.  Has anyone run into these problems before?
>>>ka-Map-users mailing list
>>>ka-Map-users at lists.maptools.org
>>|Paul Spencer                           pspencer at dmsolutions.ca   |
>>|Applications & Software Development                              |
>>|DM Solutions Group Inc                 http://www.dmsolutions.ca/|

|Paul Spencer                           pspencer at dmsolutions.ca   |
|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|

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