RE: [OpenMap Users] Discovering the minimum scale at which an RPF layer will show

From: Laura Paterson <>
Date: Mon, 7 Mar 2005 14:29:36 -0000

Hi Don,

Thank you for your reply.

> You can ask the RpfLayer for it's RpfCoverageProvider, and then ask it
> for it's coverage over a specific area. Those coverages will tell you
> what scale you need to view that data. The coverage will viewable at
> that scale * or / by the scaleFactor of that value.

Ok, I have tried that, but it doesn't quite do what I am looking for. Here
is the code that I used:

                    for (int i = 0; i < layers.length; i++) {
                        if (layers[i] instanceof RpfLayer) {

                            RpfLayer rpf = (RpfLayer)layers[i];
                            RpfFrameProvider fProvider =
                            Vector cvgs =
fProvider.getCoverage((float)minLat, (float)minLon, (float)maxLat,
(float)maxLon, (CADRG)proj);
                            for (int j=0; j<cvgs.size(); j++) {
                                RpfCoverageBox box =
                                System.out.println(layers[i].getName() + "
scale from coverage = "+box.scale);
                                minScale = Math.min(minScale, box.scale);

Unfortunately there area never any coverages for this bounding box, because
it covers such a small area...
I tried replacing the Vecor cvgs line with : Vector cvgs =
rpf.getCoverageBoxes(); However, this Vector is always empty.

I guess what am looking for (ideally!) is to be able to specify a point,
and ask at what scales will this point have rpf coverage. Is there anything
in the API that can help me achive this?


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Received on Mon Mar 07 2005 - 09:33:57 EST

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