[mapguide-internals] Avoiding unnecessary Tile Cache invalidation (Trac Ticket 1332)

Trevor Wekel trevor_wekel at otxsystems.com
Wed Apr 28 11:25:45 EDT 2010


Hi Jason,

For the AJAX viewer, the tiles are pulled by the viewer using HTTP GETTILEIMAGE(MapDefinition resourceid, tilecol, tilerow, scaleindex) and dropped on a separate div tag.  The viewer does all the processing to calculate row,col,scaleindex.  If the TileSetDefinition resource contains enough information, the AJAX viewer could just pull the resource, parse it, and grab the tiles.  GETRESOURCECONTENT already supports XML to JSON conversion so we would not even have to parse XML.

Since we have to "deprecate" APIs, we should support both MapDefinition and TileSetDefinition in GETTILEIMAGE for at least one release.  


Trevor

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Jason Birch
Sent: April 28, 2010 9:13 AM
To: MapGuide Internals Mail List
Subject: Re: [mapguide-internals] Avoiding unnecessary Tile Cache invalidation (Trac Ticket 1332)

Gmail won't let me change the follow-up subject...  :(

Anyway, I originally though the references should stay in the MapDef too,
but there are some benefits to moving it into the AppDef / WebLayout.  The
Fusion AppDev already conceptually (though possibly not functionally)
supports multiple MapGuide MapDefinitions in addition to Google, etc base
layers.

My guess would be that adding support for referencing a MapGuide tile
resource directly rather than as a MapDefinition may be easier than
modifying the MapGuide layer type to point to external MapGuide base layers,
and would be more in keeping with the general OL "layers" concept.

Not sure how this would apply to AJAX viewer though; it's likely a lot more
work on that side.

Jason

On 28 April 2010 06:19, Tom Fukushima  wrote:

> Sorry, when I wrote "This is only about the problem in the ticket", I
> should have said "This response from me is only about the problem in the
> ticket". I didn't mean to say we should ignore the "shared tile sets" idea,
> and I think it is something that is a good idea and would be good to do. I
> just don't have any input for it right now. Well, except that I think the
> reference to the tiled/base layers should stay in the MapDefinition...but
> that's just my feeling and further investigation needs to be done.
>
> Tom
>
>
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