コード例 #1
0
ファイル: makergbimages.py プロジェクト: petercamps/PTS9
def makeRGBImages(simulation,
                  wavelengthTuples=None,
                  *,
                  fileType="total",
                  fromPercentile=30,
                  toPercentile=100,
                  outDirPath=None):

    # get the (instrument, output file path) tuples to be handled
    instr_paths = sm.instrumentOutFilePaths(simulation, fileType + ".fits")
    if len(instr_paths) < 1:
        return

    # convert the wavelength tuples argument into a list of names and wavelength tuples
    if wavelengthTuples is None:
        name_waves = [("", None)]
    elif isinstance(wavelengthTuples, (tuple, list)):
        name_waves = [("_" + str(index + 1), wavetuple)
                      for index, wavetuple in enumerate(wavelengthTuples)]
    elif isinstance(wavelengthTuples, dict):
        name_waves = [("" if not name else "_" + name, wavetuple)
                      for name, wavetuple in wavelengthTuples.items()]
    else:
        raise ValueError("Invalid wavelengthTuples type")

    # loop over all wavelength tuples
    for name, wavetuple in name_waves:

        # determine the appropriate pixel range for ALL images
        ranges = []
        for instrument, filepath in instr_paths:
            image = RGBImage(
                filepath, frameIndices=instrument.wavelengthIndices(wavetuple))
            ranges += list(
                image.percentilePixelRange(fromPercentile, toPercentile))
        rmin = min(ranges)
        rmax = max(ranges)

        # create an RGB file for each output file
        for instrument, filepath in instr_paths:
            image = RGBImage(
                filepath, frameIndices=instrument.wavelengthIndices(wavetuple))
            image.setRange(rmin, rmax)
            image.applyLog()
            image.applyCurve()

            # determine output file path
            saveFilePath = ut.savePath(filepath.with_name(filepath.stem +
                                                          name + ".png"),
                                       ".png",
                                       outDirPath=outDirPath)
            image.saveTo(saveFilePath)
            logging.info("Created {}".format(saveFilePath))
コード例 #2
0
ファイル: pts_images.py プロジェクト: ntf229/RT_fit
def makeConvolvedRGBImages(simulation, contributions, name="", *, fileType="total", decades=3,
                            fmax=None, fmin=None, outDirPath=None):
    # get the (instrument, output file path) tuples to be handled
    instr_paths = sm.instrumentOutFilePaths(simulation, fileType+".fits")
    if len(instr_paths) > 0:
        name = "" if not name else "_" + name
        sbunit = sm.unit("MJy/sr")
        # construct an image object with integrated color channels for each output file
        # and keep track of the largest surface brightness value (in MJy/sr) in each of the images
        images = []
        fmaxes = []
        for instrument, filepath in instr_paths:
            logging.info("Convolving for RGB image {}{}".format(filepath.stem, name))
            # get the data cube in its intrinsic units
            cube = sm.loadFits(filepath)
            # initialize an RGB frame
            dataRGB = np.zeros( (cube.shape[0], cube.shape[1], 3) ) << sbunit
            # add color for each filter
            for band,w0,w1,w2 in contributions:
                # convolve and convert to per frequency units
                data = band.convolve(instrument.wavelengths(), cube, flavor=sbunit, numWavelengths=10)
                dataRGB[:,:,0] += w0*data
                dataRGB[:,:,1] += w1*data
                dataRGB[:,:,2] += w2*data
            # construct the image object
            images.append(vis.RGBImage(dataRGB.value))
            fmaxes.append(dataRGB.max())
        # determine the appropriate pixel range for all output images
        fmax = max(fmaxes) if fmax is None else fmax << sbunit
        fmin = fmax/10**decades if fmin is None else fmin << sbunit
        # create an RGB file for each output file
        for (instrument, filepath), image in zip(instr_paths,images):
            image.setRange(fmin.value, fmax.value)
            image.applyLog()
            image.applyCurve()
            # determine output file path
            saveFilePath = ut.savePath(filepath.with_name(filepath.stem+name+".png"), ".png", outDirPath=outDirPath)
            image.saveTo(saveFilePath)
            logging.info("Created convolved RGB image file {}".format(saveFilePath))
        # return the surface brightness range used for these images
        return fmin,fmax
コード例 #3
0
def makeWavelengthMovie(simulation,
                        *,
                        maxPercentile=100,
                        minPercentile=10,
                        decades=None,
                        renormalize=False,
                        outDirPath=None,
                        outFileName=None,
                        outFilePath=None,
                        rate=7):

    # get the list of instruments and corresponding output file paths
    instrA, sedPaths = zip(*sm.instrumentOutFilePaths(simulation, "sed.dat"))
    instrB, cubPaths = zip(
        *sm.instrumentOutFilePaths(simulation, "total.fits"))
    instrA = instrA[:3]
    instrB = instrB[:3]
    sedPaths = sedPaths[:3]
    cubPaths = cubPaths[:3]
    if len(instrA) < 1 or len(instrA) != len(instrB)  \
                       or any([ a.name() != b.name() for a,b in zip(instrA,instrB) ]):
        return
    instruments = instrA

    # get the wavelength grid for the first instrument (assumed to be the same for all instruments)
    wavelengths = instruments[0].wavelengths()
    if len(wavelengths) < 3:
        return
    nlambda = len(wavelengths)

    # load the data
    logging.info("Creating movie for {} ({} wavelengths and {} instruments)..." \
                 .format(instruments[0].prefix(), nlambda, len(instruments)))
    sedData = [
        sm.loadColumns(sedPath, "total flux")[0] for sedPath in sedPaths
    ]
    cubData = [sm.loadFits(cubPath).value for cubPath in cubPaths]

    # determine the shape (assume that frames in all fits files have the same shape)
    imgShape = cubData[0].shape[:2]
    sedShape = (len(cubData) * imgShape[0], max(imgShape[1] // 2, 300))
    totalShape = (sedShape[0], imgShape[1] + sedShape[1])

    # determine the global surface brightness range
    fmax = max(
        [np.percentile(np.unique(cube), maxPercentile) for cube in cubData])
    if decades is None:
        fmin = min([
            np.percentile(np.unique(cube), minPercentile) for cube in cubData
        ])
    else:
        fmin = fmax / 10**decades

    # determine the global integrated flux range
    Fmax = max([sed.max() for sed in sedData])
    Fmin = Fmax * fmin / fmax

    # open the movie file
    defSaveFilePath = sedPaths[0].with_name(instruments[0].prefix() +
                                            "_wavemovie.mp4")
    saveFilePath = ut.savePath(defSaveFilePath, (".mp4", ),
                               outDirPath=outDirPath,
                               outFileName=outFileName,
                               outFilePath=outFilePath)
    movie = MovieFile(saveFilePath, shape=totalShape, rate=rate)

    # for each wavelength, construct and add a movie frame
    for frame in range(nlambda):
        logging.info("  adding frame " + str(frame + 1) + "/" + str(nlambda) +
                     "...")

        # determine the surface brightness range for this frame, if needed
        if renormalize:
            fmax = max([
                np.percentile(np.unique(cube[:, :, frame]), maxPercentile)
                for cube in cubData
            ])
            if decades is None:
                fmin = min([
                    np.percentile(np.unique(cube[:, :, frame]), minPercentile)
                    for cube in cubData
                ])
            else:
                fmin = fmax / 10**decades

        # assemble the top panel
        image = None
        for cube in cubData:
            im = RGBImage(
                np.dstack((cube[:, :, frame], cube[:, :, frame], cube[:, :,
                                                                      frame])))
            im.setRange(fmin, fmax)
            im.applyLog()
            im.applyColorMap("gnuplot2")
            if image == None: image = im
            else: image.addRight(im)

        # plot the seds in the bottom panel
        dpi = 100
        figure = Figure(dpi=dpi,
                        figsize=(sedShape[0] / dpi, sedShape[1] / dpi),
                        facecolor='w',
                        edgecolor='w')
        canvas = FigureCanvasAgg(figure)
        ax = figure.add_subplot(111)
        colors = ('r', 'g', 'b')
        for sed, instrument, color in zip(sedData, instruments, colors):
            ax.loglog(wavelengths.value,
                      sed.value,
                      color=color,
                      label=instrument.name())
        ax.axvline(wavelengths[frame].value, color='m')
        ax.set_ylabel(
            sm.latexForSpectralFlux(sedData[0]) + sm.latexForUnit(sedData[0]))
        ax.set_ylim(Fmin.value / 1.1, Fmax.value * 1.1)
        ax.legend(loc='lower right', title=sm.latexForWavelength(wavelengths) \
                    + r"$={0:.4g}\,$".format(wavelengths[frame].value)+sm.latexForUnit(wavelengths))
        canvas.draw()
        im = RGBImage(figure)
        image.addBelow(im)

        # add the frame to the movie
        movie.addFrame(image)

    # close the movie file
    movie.close()
    logging.info("Created {}".format(saveFilePath))
コード例 #4
0
def plotSeds(simulation, minWavelength=None, maxWavelength=None, decades=None, *,
             outDirPath=None, outFileName=None, outFilePath=None, figSize=(8, 6), interactive=None):

    # private function to get the maximum flux within the wavelength range passed to the plotSeds function
    def maxFluxInRange(flux, wave):
        wmin = minWavelength if minWavelength is not None else wave[0]
        wmax = maxWavelength if maxWavelength is not None else wave[-1]
        mask = (wave>=wmin) & (wave<=wmax)
        if np.count_nonzero(mask) > 0:
            return flux[mask].max()
        else:
            return flux.max()

    # get the (instrument, output file path) tuples
    instr_paths = sm.instrumentOutFilePaths(simulation, "sed.dat")
    if len(instr_paths) < 1:
        return

    # setup the figure
    plt.figure(figsize=figSize)

    # if there is a single output file, and it has components, plot the components
    if len(instr_paths) == 1 and any(["transparent" in col for col in sm.getColumnDescriptions(instr_paths[0][1])]):
        instrument, filepath = instr_paths[0]
        # load the columns (we assume that all components have the same units)
        wave, tot, tra, dirpri, scapri, dirsec, scasec = sm.loadColumns(filepath, (0, 1, 2, 3, 4, 5, 6))
        waveUnit = wave.unit
        fluxUnit = tot.unit
        fluxMax = max(maxFluxInRange(tot, wave), maxFluxInRange(tra, wave))
        # plot the various components
        label = "{} {} ".format(instrument.prefix(), instrument.name())
        plt.plot(wave.value, tot.value, color='k', ls='solid', label=label + "total")
        plt.plot(wave.value, tra.value, color='b', ls='dotted', label=label + "transparent")
        plt.plot(wave.value, (dirpri + scapri).value, color='b', ls='solid', label=label + "primary")
        plt.plot(wave.value, (dirsec + scasec).value, color='r', ls='solid', label=label + "secondary")

    # otherwise loop over all SEDs
    else:
        colors = ('r', 'g', 'b', 'c', 'm', 'y')
        colorindex = 0
        first = True
        for instrument, filepath in instr_paths:
            # load the total flux; first time remember units; thereafter convert units
            wave, flux = sm.loadColumns(filepath, (0, 1))
            if first:
                waveUnit = wave.unit
                fluxUnit = flux.unit
                fluxMax = maxFluxInRange(flux, wave)
                first = False
            else:
                wave <<= waveUnit
                flux = sm.convertToFlavor(wave, flux, fluxUnit)
                fluxMax = max(fluxMax, maxFluxInRange(flux, wave))
            # plot
            plt.plot(wave.value, flux.value, color=colors[colorindex],
                     label="{} {} total".format(instrument.prefix(), instrument.name()))
            # advance color index
            colorindex = (colorindex + 1) % len(colors)

    # set axis details and add a legend
    plt.xscale('log')
    plt.yscale('log')
    plt.xlim(_adjustWavelengthRange(plt.xlim(), waveUnit, minWavelength, maxWavelength))
    if decades is not None:
        plt.ylim(fluxMax.value * 10 ** (-decades), fluxMax.value * 10 ** 0.2)
    plt.xlabel(sm.latexForWavelengthWithUnit(waveUnit), fontsize='large')
    plt.ylabel(sm.latexForSpectralFluxWithUnit(fluxUnit), fontsize='large')
    plt.legend(loc='best')

    # if not in interactive mode, save the figure; otherwise leave it open
    if not ut.interactive(interactive):
        # use the first instrument output path; if there are multiple instruments, remove the instrument name
        defSaveFilePath = instr_paths[0][1]
        if len(instr_paths) > 1:
            defSaveFilePath = defSaveFilePath.with_name(instr_paths[0][0].prefix() + "_sed.pdf")
        saveFilePath = ut.savePath(defSaveFilePath, (".pdf",".png"),
                                   outDirPath=outDirPath, outFileName=outFileName, outFilePath=outFilePath)
        plt.savefig(saveFilePath, bbox_inches='tight', pad_inches=0.25)
        plt.close()
        logging.info("Created {}".format(saveFilePath))
コード例 #5
0
ファイル: plotpolarization.py プロジェクト: petercamps/PTS9
def plotPolarization(simulation,
                     *,
                     plotLinMap=True,
                     plotDegMap=False,
                     plotDegAvg=False,
                     plotCirMap=False,
                     wavelength=None,
                     binSize=(7, 7),
                     degreeScale=None,
                     decades=5,
                     outDirPath=None,
                     figSize=(8, 6),
                     interactive=None):

    # loop over all applicable instruments
    for instrument, filepath in sm.instrumentOutFilePaths(
            simulation, "stokesQ.fits"):
        # form the simulation/instrument name
        insname = "{}_{}".format(instrument.prefix(), instrument.name())

        # get the file paths for the frames/data cubes
        filepathI = instrument.outFilePaths("total.fits")[0]
        filepathQ = instrument.outFilePaths("stokesQ.fits")[0]
        filepathU = instrument.outFilePaths("stokesU.fits")[0]
        filepathV = instrument.outFilePaths("stokesV.fits")[0]

        # load datacubes with shape (nx, ny, nlambda)
        Is = sm.loadFits(filepathI)
        Qs = sm.loadFits(filepathQ)
        Us = sm.loadFits(filepathU)
        Vs = sm.loadFits(filepathV)

        # load the axes grids (assuming all files have the same axes)
        xgrid, ygrid, wavegrid = sm.getFitsAxes(filepathI)
        xmin = xgrid[0].value
        xmax = xgrid[-1].value
        ymin = ygrid[0].value
        ymax = ygrid[-1].value
        extent = (xmin, xmax, ymin, ymax)

        # determine binning configuration
        binX = binSize[0]
        orLenX = Is.shape[0]
        dropX = orLenX % binX
        startX = dropX // 2
        binY = binSize[1]
        orLenY = Is.shape[1]
        dropY = orLenY % binY
        startY = dropY // 2

        # construct arrays with central bin positions in pixel coordinates
        posX = np.arange(startX - 0.5 + binX / 2.0,
                         orLenX - dropX + startX - 0.5, binX)
        posY = np.arange(startY - 0.5 + binY / 2.0,
                         orLenY - dropY + startY - 0.5, binY)

        # determine the appropriate wavelength index or indices
        if wavelength is None:
            indices = [0]
        elif wavelength == 'all':
            indices = range(Is.shape[2])
        else:
            if not isinstance(wavelength, (list, tuple)):
                wavelength = [wavelength]
            indices = instrument.wavelengthIndices(wavelength)

        # loop over all requested wavelength indices
        for index in indices:
            wave = wavegrid[index]
            wavename = "{:09.4f}".format(wave.to_value(sm.unit("micron")))
            wavelatex = r"$\lambda={:.4g}$".format(
                wave.value) + sm.latexForUnit(wave)

            # extract the corresponding frame, and transpose to (y,x) style for compatibility with legacy code
            I = Is[:, :, index].T.value
            Q = Qs[:, :, index].T.value
            U = Us[:, :, index].T.value
            V = Vs[:, :, index].T.value

            # perform the actual binning
            binnedI = np.zeros((len(posY), len(posX)))
            binnedQ = np.zeros((len(posY), len(posX)))
            binnedU = np.zeros((len(posY), len(posX)))
            binnedV = np.zeros((len(posY), len(posX)))
            for x in range(len(posX)):
                for y in range(len(posY)):
                    binnedI[y, x] = np.sum(
                        I[startY + binY * y:startY + binY * (y + 1),
                          startX + binX * x:startX + binX * (x + 1)])
                    binnedQ[y, x] = np.sum(
                        Q[startY + binY * y:startY + binY * (y + 1),
                          startX + binX * x:startX + binX * (x + 1)])
                    binnedU[y, x] = np.sum(
                        U[startY + binY * y:startY + binY * (y + 1),
                          startX + binX * x:startX + binX * (x + 1)])
                    binnedV[y, x] = np.sum(
                        V[startY + binY * y:startY + binY * (y + 1),
                          startX + binX * x:startX + binX * (x + 1)])

            # -----------------------------------------------------------------

            # plot a linear polarization map
            if plotLinMap:
                fig, ax = plt.subplots(ncols=1, nrows=1, figsize=figSize)

                # configure the axes
                ax.set_xlim(xmin, xmax)
                ax.set_ylim(ymin, ymax)
                ax.set_xlabel("x" + sm.latexForUnit(xgrid), fontsize='large')
                ax.set_ylabel("y" + sm.latexForUnit(ygrid), fontsize='large')

                # determine intensity range for the background image, ignoring pixels with outrageously high flux
                Ib = I.copy()
                highmask = Ib > 1e6 * np.nanmedian(np.unique(Ib))
                vmax = np.nanmax(Ib[~highmask])
                Ib[highmask] = vmax
                vmin = vmax / 10**decades

                # plot the background image and the corresponding color bar
                normalizer = matplotlib.colors.LogNorm(vmin, vmax)
                cmap = plt.get_cmap('PuRd')
                cmap.set_under('w')
                backPlot = ax.imshow(Ib,
                                     norm=normalizer,
                                     cmap=cmap,
                                     extent=extent,
                                     aspect='equal',
                                     interpolation='bicubic',
                                     origin='lower')
                cbarlabel = sm.latexForSpectralFlux(Is) + sm.latexForUnit(
                    Is) + " @ " + wavelatex
                plt.colorbar(backPlot, ax=ax).set_label(cbarlabel,
                                                        fontsize='large')

                # compute the linear polarization degree
                degreeLD = np.sqrt(binnedQ**2 + binnedU**2)
                degreeLD[degreeLD > 0] /= binnedI[degreeLD > 0]

                # determine a characteristic 'high' degree of polarization in the frame
                # (this has to be done before degreeLD contains 'np.NaN')
                charDegree = np.percentile(degreeLD, 99.0)
                if not 0 < charDegree < 1:
                    charDegree = np.nanmax((np.nanmax(degreeLD), 0.0001))

                # remove pixels with minuscule polarization
                degreeLD[degreeLD < charDegree / 50] = np.NaN

                # determine the scaling so that the longest arrows do not to overlap with neighboring arrows
                if degreeScale is None:
                    degreeScale = _roundUp(charDegree)
                lengthScale = 2.2 * degreeScale * max(
                    float(len(posX)) / figSize[0],
                    float(len(posY)) / figSize[1])
                key = "{:.3g}%".format(100 * degreeScale)

                # compute the polarization angle
                angle = 0.5 * np.arctan2(
                    binnedU, binnedQ
                )  # angle from North through East while looking at the sky

                # create the polarization vector arrays
                xPolarization = -degreeLD * np.sin(
                    angle
                )  #For angle = 0: North & x=0, For angle = 90deg: West & x=-1
                yPolarization = degreeLD * np.cos(
                    angle
                )  #For angle = 0: North & y=1, For angle = 90deg: West & y=0

                # plot the vector field (scale positions to data coordinates)
                X, Y = np.meshgrid(xmin + posX * (xmax - xmin) / orLenX,
                                   ymin + posY * (ymax - ymin) / orLenY)
                quiverPlot = ax.quiver(X,
                                       Y,
                                       xPolarization,
                                       yPolarization,
                                       pivot='middle',
                                       units='inches',
                                       angles='xy',
                                       scale=lengthScale,
                                       scale_units='inches',
                                       headwidth=0,
                                       headlength=1,
                                       headaxislength=1,
                                       minlength=0.8,
                                       width=0.02)
                ax.quiverkey(quiverPlot,
                             0.85,
                             0.02,
                             degreeScale,
                             key,
                             coordinates='axes',
                             labelpos='E')

                # if not in interactive mode, save the figure; otherwise leave it open
                if not ut.interactive(interactive):
                    saveFilePath = ut.savePath(
                        filepath,
                        ".pdf",
                        outDirPath=outDirPath,
                        outFileName="{}_{}_pollinmap.pdf".format(
                            insname, wavename))
                    plt.savefig(saveFilePath,
                                bbox_inches='tight',
                                pad_inches=0.25)
                    plt.close()
                    logging.info("Created {}".format(saveFilePath))

            # -----------------------------------------------------------------

            # plot a linear polarization degree map
            if plotDegMap:
                fig, ax = plt.subplots(ncols=1, nrows=1, figsize=figSize)

                # configure the axes
                ax.set_xlim(xmin, xmax)
                ax.set_ylim(ymin, ymax)
                ax.set_xlabel("x" + sm.latexForUnit(xgrid), fontsize='large')
                ax.set_ylabel("y" + sm.latexForUnit(ygrid), fontsize='large')

                # calculate polarization degree for each pixel, in percent
                # set degree to zero for pixels with very low intensity
                cutmask = I < (np.nanmax(
                    I[I < 1e6 * np.nanmedian(np.unique(I))]) / 10**decades)
                degreeHD = np.sqrt(Q**2 + U**2)
                degreeHD[~cutmask] /= I[~cutmask]
                degreeHD[cutmask] = 0
                degreeHD *= 100

                # plot the image and the corresponding color bar
                vmax = degreeScale if degreeScale is not None else np.percentile(
                    degreeHD, 99)
                normalizer = matplotlib.colors.Normalize(vmin=0, vmax=vmax)
                backPlot = ax.imshow(degreeHD,
                                     norm=normalizer,
                                     cmap='plasma',
                                     extent=extent,
                                     aspect='equal',
                                     interpolation='bicubic',
                                     origin='lower')
                plt.colorbar(backPlot, ax=ax).set_label(
                    "Linear polarization degree (%)" + " @ " + wavelatex,
                    fontsize='large')

                # if not in interactive mode, save the figure; otherwise leave it open
                if not ut.interactive(interactive):
                    saveFilePath = ut.savePath(
                        filepath,
                        ".pdf",
                        outDirPath=outDirPath,
                        outFileName="{}_{}_poldegmap.pdf".format(
                            insname, wavename))
                    plt.savefig(saveFilePath,
                                bbox_inches='tight',
                                pad_inches=0.25)
                    plt.close()
                    logging.info("Created {}".format(saveFilePath))

            # -----------------------------------------------------------------

            # plot the y-axis averaged linear polarization degree
            if plotDegAvg:
                # construct the plot
                fig, ax = plt.subplots(ncols=1, nrows=1, figsize=figSize)
                degreeHD = np.sqrt(
                    np.average(Q, axis=0)**2 + np.average(U, axis=0)**2)
                degreeHD /= np.average(I, axis=0)
                ax.plot(xgrid.value, degreeHD * 100)
                ax.set_xlim(xmin, xmax)
                ax.set_ylim(0, degreeScale)
                ax.set_title("{}   {}".format(insname, wavelatex),
                             fontsize='large')
                ax.set_xlabel("x" + sm.latexForUnit(xgrid), fontsize='large')
                ax.set_ylabel('Average linear polarization degree (%)',
                              fontsize='large')

                # if not in interactive mode, save the figure; otherwise leave it open
                if not ut.interactive(interactive):
                    saveFilePath = ut.savePath(
                        filepathI,
                        ".pdf",
                        outDirPath=outDirPath,
                        outFileName="{}_{}_poldegavg.pdf".format(
                            insname, wavename))
                    plt.savefig(saveFilePath,
                                bbox_inches='tight',
                                pad_inches=0.25)
                    plt.close()
                    logging.info("Created {}".format(saveFilePath))

            # -----------------------------------------------------------------

            # plot a circular polarization map
            if plotCirMap:
                fig, ax = plt.subplots(ncols=1, nrows=1, figsize=figSize)

                # configure the axes
                ax.set_xlim(xmin, xmax)
                ax.set_ylim(ymin, ymax)
                ax.set_xlabel("x" + sm.latexForUnit(xgrid), fontsize='large')
                ax.set_ylabel("y" + sm.latexForUnit(ygrid), fontsize='large')

                # determine intensity range for the background image, ignoring pixels with outrageously high flux
                Ib = I.copy()
                highmask = Ib > 1e6 * np.nanmedian(np.unique(Ib))
                vmax = np.nanmax(Ib[~highmask])
                Ib[highmask] = vmax
                vmin = vmax / 10**decades

                # plot the background image and the corresponding color bar
                normalizer = matplotlib.colors.LogNorm(vmin, vmax)
                cmap = plt.get_cmap('PuRd')
                cmap.set_under('w')
                backPlot = ax.imshow(Ib,
                                     norm=normalizer,
                                     cmap=cmap,
                                     extent=extent,
                                     aspect='equal',
                                     interpolation='bicubic',
                                     origin='lower')
                cbarlabel = sm.latexForSpectralFlux(Is) + sm.latexForUnit(
                    Is) + " @ " + wavelatex
                plt.colorbar(backPlot, ax=ax).set_label(cbarlabel,
                                                        fontsize='large')

                # compute the circular polarization degree
                degreeLD = binnedV.copy()
                degreeLD[binnedI > 0] /= binnedI[binnedI > 0]

                # determine the scaling and add legend
                if degreeScale is None:
                    degreeScale = _roundUp(np.percentile(np.abs(degreeLD), 99))
                lengthScale = 0.7 / max(len(posX), len(posY))
                _circArrow(ax, 0.84 - lengthScale / 2, 0.01 + lengthScale / 2,
                           lengthScale)
                key = r'$+{} \%$'.format(100 * degreeScale)
                ax.text(0.85,
                        0.01 + lengthScale / 2,
                        key,
                        transform=ax.transAxes,
                        ha='left',
                        va='center')

                # actual plotting
                for x in range(len(posX)):
                    for y in range(len(posY)):
                        if np.isfinite(degreeLD[y, x]) and abs(
                                degreeLD[y, x]) > degreeScale / 50:
                            _circArrow(
                                ax, posX[x] / orLenX, posY[y] / orLenY,
                                degreeLD[y, x] / degreeScale * lengthScale)

                # if not in interactive mode, save the figure; otherwise leave it open
                if not ut.interactive(interactive):
                    saveFilePath = ut.savePath(
                        filepath,
                        ".pdf",
                        outDirPath=outDirPath,
                        outFileName="{}_{}_polcirmap.pdf".format(
                            insname, wavename))
                    plt.savefig(saveFilePath,
                                bbox_inches='tight',
                                pad_inches=0.25)
                    plt.close()
                    logging.info("Created {}".format(saveFilePath))