[ka-Map-users] ka-Map and OpenLayers

Paul Spencer pspencer at dmsolutions.ca
Wed Jun 21 08:18:12 EDT 2006


I would retain the tile creation/caching mechanism (and actually have  
plans to improve it somewhat), either as part of OpenLayers or as a  
separate project.  This would still be directly dependent on  
MapServer, although as I mentioned to Steve, MapGuide also supports  
tile creation and caching.  Geoserver and Deegree might follow suit  
if we can provide a convincing standards-based API that they can  
support, which would mean that all the major open source map- 
producing engines would serve cached tiles in the same way.

Concerning the code, I think that most of the core engine would be  
discarded, except for the optimizations for the optimizations for  
reusing images when panning.  As you point out, this was a fair  
amount of effort.  However, at this point I am mostly convinced that  
the core of OpenLayers works in the same fashion and so its not  
really discarding it as much as avoiding extra work re-writing it  
into a better architecture :)

There is quite a bit of the ka-Map code that would be retained in my  
world :)  This would be most of the extra stuff around the core API,  
including most of the work done by Pg, Andrea and Lorenzo.  This  
would include the UI elements, overlay stuff, etc.  Most of this code  
won't need substantial changes to work with OpenLayers (I hope/expect).

Overall, I would expect this merger to produce a more solid code base  
that combines the best of both projects, has a bigger developer and  
user community and sees wider recognition as an OSGeo project (my  
ultimate goal :)).



On 20-Jun-06, at 7:49 PM, Delfos, Jacob wrote:

> Paul,
> Would that mean you would basically replace the interface of Ka- 
> Map, and
> retain the tile-creating mapserver-based mechanism? To what degree  
> would
> it still be mapserver-oriented?
> Approximately which core parts of Ka-Map do you think could be  
> retained,
> and what would definitely be lost? It sounds like you would need to  
> get
> rid of a lot of work you did...
> Regards,
> Jacob
>> -----Original Message-----
>> From: ka-map-users-bounces at lists.maptools.org
>> [mailto:ka-map-users-bounces at lists.maptools.org] On Behalf Of
>> Paul Spencer
>> Sent: 21 June 2006 02:28
>> To: ka-map-users at lists.maptools.org ML
>> Subject: [ka-Map-users] ka-Map and OpenLayers
>> Hello ka-Mappers!
>> I had a very interesting discussion with the developers of
>> OpenLayers, a javascript api for tiled maps.  Turns out OpenLayers
>> and ka-Map are very similar.  We decided that it would be beneficial
>> for both communities if we attempted to merge the projects.  The
>> purpose of this email is to present this idea to the ka-Map
>> community
>> in order to generate some discussion on the subject.
>> OpenLayers is hosted at http://www.openlayers.org/.  They have some
>> very interesting objectives which I think are compatible with ka-
>> Map.  Take a look at their site.
>> OpenLayers is written on top of prototype.js, which was one of the
>> things I was planning to do with ka-Map in the next couple of
>> weeks.
>> It has a very nice looking architecture and the code base is very
>> readable.
>> It is lacking quite a few things that ka-Map has:
>> * core tiling engine is very similar, but it is not quite as optimal
>> (doesn't reuse images for instance)
>> * overlay stuff is point/text only
>> * lacking tools (layer controls, scale bar etc) and the
>> windowing stuff
>> * lacking query capability
>> * tile caching
>> * probably several other things I can't think of right now
>> I think that there are some differences in how OpenLayers and ka-Map
>> approach things, but I'm not entirely sure that they are significant.
>> At this point, I am proposing to join the two projects into a single
>> project.  My desired approach would be to start with the OpenLayers
>> code and start to bring over the parts of ka-Map that I(we) feel are
>> missing.
>> Please let me know what you think of this.  And point out all the
>> problems you can think of.
>> Cheers
>> Paul
>> +-----------------------------------------------------------------+
>> |Paul Spencer                           pspencer at dmsolutions.ca   |
>> +-----------------------------------------------------------------+
>> |Applications & Software Development                              |
>> |DM Solutions Group Inc                 http://www.dmsolutions.ca/|
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|Paul Spencer                           pspencer at dmsolutions.ca   |
|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|

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