[mapguide-internals] RFC required for tile caching changes?

[Andy Morsell]

That really does seem a logical progression and would reduce having to
maintain redundant base map layers from map to map in addition to making
sure tiles based on those same base map layers are only generated once.  It
seems that this might require a new object type in the repository - say a
BaseMap object that could then be referenced by any normal map.


Andy 

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Paul
Spencer
Sent: Friday, January 12, 2007 10:51 AM
To: MapGuide Internals Mail List
Subject: Re: [mapguide-internals] RFC required for tile caching changes?

Chris,

This is probably beyond the scope of what you would like to do, but it does
involve cache optimization.  Imagine I have a bunch of really good data (say
NavTeq for example) and I've built up a library of layer styling that I
really like.  I want to use these layers as a tiled layer in several
applications that need different MapDefinitions but all share the same base
tile layer.  It would be really nice if the cache for each map could point
to a common location for the tiles.

As you are already re-jigging the tiling mechanism, is there a way that you
could incorporate this kind of flexibility?

Cheers

Paul

On 12-Jan-07, at 1:39 PM, Chris Claydon wrote:

> We have found that problems can occur if too many cached tile images 
> are stored in a single folder on the hard drive. For this reason, I 
> have some changes to submit that ensure that we only store 900 tiles 
> per folder (in 30 x 30 blocks).
>
> This changes the locations of stored tiles, by introducing new 
> subfolders, and will thus "orphan" any tiles already created by the 
> cache. Since the root folder for the tiles for any given map will not 
> change, these orphaned tiles will be cleaned up if the user modifies 
> the map definition or makes a call to the Clear(MgMap* map) method in 
> the tile service API. The user could also force the cleanup simply by 
> deleting the contents of the root cache folder when they upgrade to 
> the version containing these changes.
>
> I'd like to treat this submission as a simple defect fix, but the 
> requirement for the extra cleanup steps may indicate that an RFC is 
> required, and I'd like to know the opinions of the PSC on this matter.
>
> Also, please let me know if you require any further information about 
> this submission.
>
> Cheers,
>
> Chris Claydon.
>
> _______________________________________________
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> mapguide-internals at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapguide-internals

+-----------------------------------------------------------------+
|Paul Spencer                          pspencer at dmsolutions.ca    |
+-----------------------------------------------------------------+
|Chief Technology Officer                                         |
|DM Solutions Group Inc                http://www.dmsolutions.ca/ |
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