[ka-Map-users] Architectural questions.

[Christopher Schmidt]

On Tue, Nov 06, 2007 at 08:19:14AM -0800, The Bun wrote:
> 
> I have few architectural questions. Mainly, is regarding kaMap and
> OpenLayers, they both seems to be client-side ajax package right? Plus kamap
> has some PHP back end for tiling while OL has something called TileCache,
> right?

TileCache is a seperate software package which can be used, not
explicitly tied to OpenLayers. (Users have used it with WorldWind and
other similar code in the past.)

ka-Map is clientside code which is primarily designed to talk to its
server side API and configuration, in tile.php / config.php . 

OpenLayers can talk to the tile.php part of ka-Map via its KaMap layer. 

> I currently have developed some prototypes based on a MapServer plus a
> customized kaMap. I have read that kaMap is implementing, is going to
> implement OL, I am not sure I quite understand what that means, is means
> kaMap is going to wrap JavaScript functionalities like zooming, panning etc
> of OL? 

Yes -- OpenLayers will be used for the map drawing, with ka-Map acting
as a layer on top of that ot provide functionality like ka-Explorer and
searching.

> On the other side I see that from OL you can actually working with
> kaMap layers ( although I couldn't test it), I really don't understand what
> is the utility for doing that.

So that if you already have a working ka-Map cache, you can use that
instead of creating a new one.

> On the OL forums I read that OpenLayers may runs in the browser and accesses
> ka-map tiling code running on the server, which in turn calls MapServer.

Right.

> On this forum I read that kamappers developers are going to implement OL in
> kaMap.
> 
> I am struggling to understand what are the essential pieces of the puzzle I
> need and what I have to expect for the future, seems that many people who
> has used kaMap are going for a mixed solution or a full solution with OL and
> TileCache.

Okay. Here's one way to look at it.

Currently:

   Tile Backends                             
 
     tile.php  < - - - - <-- ka-map  - - - > User interface,       
                     \                       Searching interface, etc. 
    TileCache    <--  \ OpenLayers
                      /
     Others  < - - - -

In the future:
     
     tile.php  < - -         
                     \ OpenLayers <-- ka-map  - - - > User interface, 
                     /                               Searching interface, etc. 
    TileCache  < - - 

That is:

Currently, ka-Map talks directly to tile.php, and for the most part,
only tile.php. OpenLayers talks to many different tile sources.

ka-Map provides a query interface, user interface, etc. while OpenLayers
is primarily a tile loading library.

In the future, instead of ka-Map implementing the tile drawing code, it
could use OpenLayers to draw the tiles, and still maintain its own code
to do the user interface, searching against MapServer, etc.

This is the route that MapBuilder has taken, using OWS-Context for
configuration, creating a UI on top of OpenLayers using XML as a
description language.

OpenLayers is a library for building applications. ka-Map is an
application, which could use the OpenLayers library. (Think about it as
the difference between GDAL and qgis, if that means anything to you.)

Regards,
-- 
Christopher Schmidt
Web Developer