Ok, I understand your requirement better now.
The way to ensure the heatmap has the same appearance at all zoom levels is
to express the kernel radius in ground units, rather than pixels. The
heatmap process doesn't support this at the moment, but it's a fairly easy
thing to add.
The heatmap process already performs an internal expansion of the request
bbox, in order to ensure that the displayed heatmap is stable under
panning. I have a feeling this may not be working correctly, however.
Martin
On Thu, Jul 26, 2012 at 1:22 AM, Mario Basa <[email protected]> wrote:
> Thank you very much for the reply, Martin.
>
> Yes changing the wms_bbox might not have been a good idea.
>
> But is there anyway to force it so that the attribute data of the entire
> layer is always read, instead of just reading the data that is within the
> wms_bbox.
>
> What we are hoping for is that the heat map itself does not change in a
> pan or zoom event.
>
> Thanks once more.
>
> Mario.
>
>
>
> On Thu, Jul 26, 2012 at 12:14 AM, Martin Davis <[email protected]> wrote:
>
>> A further comment on this - if you precompute the heatmap, then the
>> resolution will be fixed, so zooming in may result in low-quality display.
>> This is one reason the heatmap RT was originally developed - to provide
>> full resolution display at all scales.
>>
>>
>> On Tue, Jul 24, 2012 at 12:28 PM, Martin Davis <[email protected]>wrote:
>>
>>> Actually, no it isn't. There's two reasons for that:
>>>
>>> 1. The outputBBOX parameter is used to determine the extent for the
>>> computed heatmap. This needs to match the requested image extent
>>> (otherwise you would get a distorted output)
>>> 2. Even if you could use a different outputBBOX, the heatmap image is
>>> still computed each time a map request is processed. So there would be no
>>> performance advantage to doing this (in fact, there would be a performance
>>> degradation).
>>>
>>> It sounds like what you want to do is to pre-compute a heatmap raster
>>> for the entire dataset and then view it as a layer. Because the heatmap RT
>>> is a WPS process it should be possible to call it as a WPS and store the
>>> result raster as a new layer in GeoServer. I've never tried doing this -
>>> try it and report back! (Note: you will have to provide output image
>>> extents that match the aspect ratio of the dataset BBOX. )
>>>
>>> On Tue, Jul 24, 2012 at 12:26 AM, Mario Basa <[email protected]>wrote:
>>>
>>>> Hello,
>>>>
>>>> Is it possible to set the outputBBOX parameter described here:
>>>>
>>>>
>>>> http://docs.geoserver.org/stable/en/user/styling/sld-extensions/rendering-transform.html#heatmap-generation
>>>>
>>>> to the extent of the entire point layer instead of the wms_bbox sld
>>>> parameter? This is because I don't want to change (re-calculated to the
>>>> points of wms_bbox extent) the heatmap whenever there is a panning or zoom
>>>> event.
>>>>
>>>> If it is possible to set the extent, what will the syntax be (i.e.
>>>> BBOX(x1 y1,x2 y2)) ?
>>>>
>>>> Thanks and regards,
>>>>
>>>> Mario.
>>>>
>>>>
>>>>
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>>>
>>>
>>> --
>>> Martin Davis
>>> OpenGeo - http://opengeo.org
>>> Expert service straight from the developers.
>>>
>>>
>>
>>
>> --
>> Martin Davis
>> OpenGeo - http://opengeo.org
>> Expert service straight from the developers.
>>
>>
>
--
Martin Davis
OpenGeo - http://opengeo.org
Expert service straight from the developers.
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Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
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