[mapguide-internals] Dynamic tile rendering proposal

[Zac Spitzer]

How does exposing mapDefinition's as WMS sound as a solution?

On Thu, Jul 31, 2008 at 11:02 PM, Kenneth Skovhede, GEOGRAF A/S
<ks at geograf.dk> wrote:
> As I understand meta tiling, it works by creating a larger image than the
> one requested (smaller),
> in anticipation of requests to similar/adjacent (smaller) images.
>
> In a sense, that is what I want, but I would request the larger image, and
> retrieve the sub-tiles.
> Unlike meta-tiling, the purpose of this feature is not to create extra data
> in advance,
> but rather serve a large image in smaller chunks.
>
> If the server renders the entire image and just hands out the smaller
> images, I would not
> expect the percieved transmission time to diminish, as the crucial part is
> the time that goes
> before the initial image is displayed.
>
> From a users perspective, a long but visible progress, is better than a
> shorter uncertain wait.
> (Within certain bounds of course)
>
> Regards, Kenneth Skovhede, GEOGRAF A/S
>
>
>
> Zac Spitzer skrev:
>>
>> Kenneth, do you think meta tiling could also solve this problem?
>>
>> On Thu, Jul 31, 2008 at 7:20 PM, Kenneth Skovhede, GEOGRAF A/S
>> <ks at geograf.dk> wrote:
>>
>>>
>>> The current tile mechanism is using static images to serve pre-built
>>> images
>>> as tiles.
>>> For this reason, the tiles are only usefull with "base layers".
>>>
>>> I have worked with OpenLayers, and it has a very nice tiling mechanism.
>>> DM Solutions have built some tiling support into the MapGuide provider
>>> for
>>> OpenLayers.
>>> This uses the static tiles, and the row/column index system in MapGuide.
>>>
>>> Using the "original" OpenLayers tiling mechanism one can get a dynamic
>>> MapGuide image
>>> to load as tiles, giving the illusion that the page loads faster (when it
>>> actually loads a bit slower).
>>>
>>> The problem with this method is that MapGuide optimizes the rendered
>>> image
>>> for the given bounds.
>>> This is especially true for calculating label positions and overlaps.
>>> I would like to add a parameter for the "GETMAPIMAGE" call that accepts
>>> an
>>> "outer bounds" parameter.
>>>
>>> With this parameter, MapGuide should render the extent given by the
>>> extent
>>> parameter, but use the outer
>>> bounds for determining label placements and any other details that may
>>> have
>>> the same problems.
>>>
>>> With this, it would be possible for MapGuide to serve tiles from
>>> MapGuide,
>>> without relying on a
>>> static tilcache.
>>>
>>>
>>> I would like to add this as an RFC, but would like feedback on the idea,
>>> as
>>> well as possible problems.
>>>
>>> --
>>> Regards, Kenneth Skovhede, GEOGRAF A/S
>>>
>>>
>>> _______________________________________________
>>> mapguide-internals mailing list
>>> mapguide-internals at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/mapguide-internals
>>>
>>>
>>
>>
>>
>>
>
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>



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