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Re: [udig-devel] custom wms renderer
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On Thu, Apr 21, 2011 at 8:58 AM, Devrim Baris Acar
<devrimbaris@xxxxxxxxx> wrote:
> Hi,
> I have developed a custom wms renderer for udig which holds a reference to
> the original coverage retrieved from geoserver(raw geotiff crop ).
>
> I have noticed a considerable slowdown as geotiff sizes get bigger (>20
> seconds )
>
> I have pinned the problem to be the following lines
>
> ----------------------------------------------
> inputStream = wms.issueRequest(request).getInputStream();
> image[0] = ImageIO.read(inputStream);
> ----------------------------------------------
>
> Now I have tested with various java codes for streams, command line tools
> like "wget", "curl".
>
> Command line tools retrieve the image in nearly 2 seconds.
> Java code with buffered streams retrieve image in 20 seconds.
>
>
> So I have used Apache Commons HTTPClient to retrieve the image, stored in a
> file, and let ImageIO stream from the filestream, now the responses are 3-4
> seconds, which is much more acceptable.
>
>
> That leaves the question to how ImageIO.read works in internals .
ImageIO needs random access readers and writers, if you provide a stream
you force it to copy the file in a random access container (either another file
or a byte[] in memory) and decode the images from there, depending
on how ImageIO is configured (by default it will work on a file).
Cheers
Andrea
--
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Ing. Andrea Aime
GeoSolutions S.A.S.
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