[visad] Polar Representation Radar Data

• To: visad@xxxxxxxxxxxxxxxx
• Subject: [visad] Polar Representation Radar Data
• From: Marco Aurelio Silva Neto <marcoaurelioneto@xxxxxxxxxxxx>
• Date: Thu, 2 Jul 2009 06:41:16 -0700 (PDT)

Hi VisAD people,

I am using the visad.bom.Radar2DCoordinateSystem to resample and
visualize some radar data.

As we can see in the picture "radar_Linear2DSet.png", the data are not in polar 
representation.

This is happening because I might be using the method Linear2DSet.

What is the correct way to make the representation in polar coordinates?

The Application Unidata IDV (see picture "radar_polar_IDV.png") is the 
representation of data from radars in polar coordinates equal to I want to do. 
How?

Following excerpt from my source code:


/*********************************/

setRadar = new Linear2DSet(domain_tuple, radarlimites[2], radarlimites[3],
                    800, radarlimites[0], radarlimites[1],
                    360);

latMap.setRange(radarlimites[2], radarlimites[3]);
lonMap.setRange(radarlimites[0], radarlimites[1]);

vals_ff = getFieldPolar((int) srf.getNumero_BINS_ou_Linhas(),
                        (int) srf.getNumero_Raios_ou_Colunas(),
                        (float) srf.getLatitude(), (float) srf.getLongitude(),
                        srf.getTamanho_Bin_ou_celula(), srf.getDados());

vals_ff = (FlatField) vals_ff.resample(setRadar, visad.Data.NEAREST_NEIGHBOR,
                        visad.Data.NO_ERRORS);

radarMap.setRange(0, 72);

ColorAlphaControl rgbControl = (ColorAlphaControl) radarMap.getControl();

cores = new float[][]{{0f, 0.98f, 0f}, {0f, 0.81f, 0f}, {0f, 0.7f, 0f}, {0f, 
0.59f, 0f}, {0f, 0.47f, 0f}, {0f, 0.33f, 0f}, {0f, 0.22f, 0f}, {0.98f, 0.95f, 
0f}, {0.96f, 0.88f, 0f}, {0.96f, 0.82f, 0f}, {0.95f, 0.76f, 0f}, {0.91f, 0.55f, 
0f}, {0.9f, 0.48f, 0f}, {0.98f, 0f, 0f}, {0.87f, 0f, 0f}, {0.78f, 0f, 0f}, 
{0.72f, 0f, 0f}, {0.65f, 0f, 0f}, {1f, 0.62f, 1f}, {0.98f, 0.13f, 0.98f}, 
{0.88f, 0.13f, 0.88f}, {0.80f, 0.13f, 0.92f}, {0.69f, 0.16f, 0.86f}, {0.63f, 
0.17f, 0.84f}, {0.57f, 0.17f, 0.80f}};

//Seta a escala de cores
rgbControl.setTable(RadarCalculos.getCoresVisad(cores));

//Toca plotar
if (radarRef == null) {
        radarRef = new DataReferenceImpl("radarref");
        displayImpl.addReference(radarRef);
}
radarRef.setData(vals_ff);


/*********************************/

        method getFieldPolar

/*********************************/

private FlatField getFieldPolar(int beans, int rays, final float lat,
            final float lon, final float dist, final float[][] data) {
        try {
            reflection1 = RealType.getRealType("reflection");
            azimuth = RealType.getRealType("azimuth", CommonUnit.degree, null);
            range = RealType.getRealType("range", CommonUnit.meter, null);

            polarCoords = new Radar2DCoordinateSystem(lat, lon, dist, dist, 0f, 
1.003f);

            polarTuple = new RealTupleType(new RealType[]{range, azimuth}, 
polarCoords, null);
            polarFunc = new FunctionType(polarTuple, reflection);

            latLonTuple = new RealTupleType(RealType.Latitude, 
RealType.Longitude);
            latLonFunc = new FunctionType(latLonTuple, reflection);

            //Copia os dados para uma matriz com um raio a mais (361 - rays + 1)
            //O Visad exige que o último raio seja igual ao primeiro
            float[][] dados = new float[1][(rays + 1) * beans];
            for (int i = 0; i < rays + 1; i++) {
                for (int j = 0; j < beans; j++) {
                    if (i != rays) {
                        dados[0][i * beans + j] = data[0][i * beans + j];
                    } else {
                        dados[0][i * beans + j] = data[0][0 * beans + j];
                    }
                    if (Float.isNaN(dados[0][i * beans + j])) {
                        dados[0][i * beans + j] = -999.9f;
                    }
                }
            }

            Set set = new Integer2DSet(polarTuple, beans, rays + 1);//rays+1 
para termos 361 raios

            FlatField flatField = new FlatField(polarFunc, set);

            flatField.setSamples(dados, true);
            return flatField;
        } catch (RemoteException ex) {
            Logger.getLogger(DisplayVisad.class.getName()).log(Level.SEVERE, 
null, ex);
        } catch (VisADException ex) {
            Logger.getLogger(DisplayVisad.class.getName()).log(Level.SEVERE, 
null, ex);
        }
        return null;
    }


/*********************************/



Thanks
Marco Aurélio Silva Neto 


      
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Attachment: radar_Linear2DSet.png
Description: PNG image

Attachment: radar_polar_IDV.png
Description: PNG image