Re: [OpenMap Users] ImageTileLayer imageCutoffScale/imageCutoffRatio

From: Don Dietrick <>
Date: Thu, 17 Mar 2011 11:55:22 -0400

Hi Pete,

Sorry for the mixup in the javadocs, I've fixed it.

What is your value for the ratio? By default it's 5, so if you use
the value in the javadocs (1000000 or something like that), you
probably will see the image all the time. I usually don't set a value
for that property and go with the default, and that's been working for
me, so I'm guessing that might be the problem.

The calculated image scale cutoff might vary a bit based on the
projection parameters. The ratio setting is going against what the
scale would be for the image for the current projection, and that
calculation might give out different results under different
projection conditions - the calculation being used is the one used for
calculating the zoom scale to fit a box on the current map, so it kind
of depends on the h/w of the map window, pixel spacings, and
projection type, so it's not that exact.

For better performance, you might want to use GDAL to create map tiles
(TMS format) from the GeoTIFF, and then use the MapTileLayer to
display those tiles. That's in the beta.

Hope this helps,


On Thu, Mar 17, 2011 at 10:22 AM, Pete Flugstad <> wrote:
> Hello,
>  I'm using ImageTileLayer, and I'd like to set the imageCutoffScale
> value to limit the display
> of some Geotiffs. However, it looks like the actual property name is
> imageCutoffRatio
> (java doc is incorrect).
>  However, when I try and use imageCutoffRatio, it doesn't seem to be
> working as I expected.
> No matter how far out I zoom, my images are still being display
> (eventually they end up being
> a dot on the map).  So maybe I'm not understanding what imageCutoffRatio is for?
>  In debugging, it looks like this ratio value is getting used in
> ImageTile.shouldFetchForProjection.
> It's calculating the image scale and comparing that to the projection
> scale.  The project scale
> goes up as I zoom out, but the calculated imageScale seems to go up as
> the projection zooms
> out as well, which is confusing to me - I would expect it to be fixed
> based on the image?  What
> am I missing?
> Thanks,
> Pete
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Received on Thu Mar 17 2011 - 11:58:13 EDT

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