[webmap-discuss] OGC and google style tiling

[Paul Spencer]

What would be really nice would be to have a MapBuilder widget for ka- 
Map ;)  Mike Adair has mentioned that this is both possible and quite  
easy to do.  Not being very familiar with MapBuilder, I can't comment  
on that.  But if it were possible to do, ka-Map would provide you a  
tiled interface and you could use your existing map file to do it  
without breaking ogc compatibility.

Cheers

Paul


On 12-Apr-06, at 4:33 AM, Steven M. Ottens wrote:

> Hi Bart,
>
> Thanks for the mailinglist tip.
> It might be possible to rasterize our vector data, but we've got quite
> some datasets and there will be more of them. It also makes us less
> flexible. Obviously we've to make a trade-off on flexibility and  
> speed.
> We hope that with cached tiles we can have both the flexibility and
> speed. If we rasterise it would make sense to rasterise into fixed  
> tiles
> I guess.
>
> Steven
>
> Bart van den Eijnden wrote:
>> Hi Steven,
>>
>> there is an OGC list to discuss tiling:
>>
>> http://lists.eogeo.org/mailman/listinfo/tiling
>>
>> check the archives there.
>>
>> What you could also do, since I assume your data is pretty much  
>> static, is
>> use UMN Mapserver to rasterize all your vector data (create  
>> Geotiffs e.g.)
>> and serve out the rasters instead. I guess the classifications  
>> used are
>> heavy on CPU usage, and pre-classified rasters would solve that  
>> part at
>> least.
>>
>> Best regards,
>> Bart
>>
>>
>>> Hi all,
>>>
>>> For those who don't know: I'm one of the lead developers on the  
>>> EduGIS
>>> project, a site which aims to introduce highschool students to  
>>> GIS. The
>>> site contains a webmapping part, which combined with so called
>>> 'lesson-modules' can be used inside the classroom.
>>> We aim to be able to have at least 200 students access the site  
>>> at one
>>> time. Since it's being used inside the classroom it means that a  
>>> lot of
>>> students will do more or less the same thing at the same time  
>>> (following
>>> the tasks in the lesson-modules). This causes quite some stress  
>>> on the
>>> server. Since it's a free site we have limited budget and cannot  
>>> put a
>>> google-style server park behind it ;(
>>>
>>> Right now we've got apache to serverside cache the umn mapserver  
>>> output.
>>> This obviously works only for those images that are requested twice
>>> (like the first mapimage). Right now about 30 students can work  
>>> at the
>>> same time without it becoming unworkable slow. Since serverside  
>>> caching
>>> works, the next logical step to boost performance would be using  
>>> tiles
>>> like google.
>>> But..
>>> From what I know, tiling breaks OGC compatibility, right?
>>> We're using Mapbuilder as client and we prefer to keep using it,  
>>> since
>>> it's turning into a rather featureful client on the EduGIS site.  
>>> But the
>>> question arises how to implement tiling inside WMC/OWS-context  
>>> without
>>> breaking OGC too much.
>>> Also I'm interested in the used algorithms to get tiling working.
>>>
>>> Cheers,
>>> Steven
>>>
>>>
>>>
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>>
>>
>>
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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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