S Dille wrote:
> Hi,
> I have a question about rendering images. What would cause a 8 MB jpg
> file to take about 20 minutes to render, while a 5 MB TIF file renders in
> about 1 second? I am simply opening these in a JMapPane, while using a
> StreamingRenderer and I'm kind of lost on how to increase rendering
> performance for images. Both files are georeferenced with projection and
> world files. Below is my code for inserting the images:
>
> AbstractGridFormat format = GridFormatFinder.findFormat(imageFile);
> readImage = format.getReader(imageFile); //readImage is an
> AbstractGridCoverage2DReader object
>
> GridCoverage2D covLayer = null;
> try {
> covLayer = (GridCoverage2D) readImage.read(null);
> } catch (Exception e) {
> e.printStackTrace();
> }
>
> mapContext.addLayer(covLayer,Style);
>
>
> I know this is a pretty general question, but are there any image or JAI
> experts that can point me in the right direction on how I can find out why
> some files take so long to render, while other similarly sized images load
> quickly?
Most likely because the tiff is not compressed whilst the jpeg is.
And the jpeg has to be fully decompressed in memory before being
used, an 8MB jpeg is also a huge image
As a rule of thumb stay away from jpeg and use tiff files with
overviews and inner tiling if you want good rendering performance
Cheers
Andrea
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