예제 #1
0
파일: __init__.py 프로젝트: yaswant/ypylib
    def to_csv(self, filename):
        """Save data to comma separated value (csv) file.

        Limitation: Currently works with 1D arrays only.

        Parameters
        ----------
        filename : str
            A string for output csv filename.

        See also
        --------
        to_txt  Save records to text file and with more control and better
                performance.

        TODO: Auto generate filename
        """
        def fields_view(arr, fields):
            """Create columns views of a structured array.

            Parameters
            ----------
            arr : array
                numpy structured array
            fields : list of str
                list of fields to view in specific order
            """
            # dtype2 = np.dtype(
            #     {name: arr.dtype.fields[name] for name in fields})
            dtype2 = np.dtype(
                dict((name, arr.dtype.fields[name]) for name in fields))
            return np.ndarray(arr.shape, dtype2, arr, 0, arr.strides)

        if self.mdb_extract or self.data is None:
            data = self.extract()
        else:
            log.info('Skip MDB_EXTRACT.')
            data = self.data

        if data is None:
            return

        # save data to csv
        with open(filename, 'wb') as fh:
            write = writer(fh)
            write.writerow(self.elements)
            write.writerows(fields_view(data, self.elements))
        log.info('File saved: %s', filename)
예제 #2
0
파일: __init__.py 프로젝트: yaswant/ypylib
    def to_txt(self, filename, delimiter=',', fmt=None):
        """Save data to a text file.

        Limitation: Currently works with 1D arrays only.

        Preferred over to_csv() for speed and control.

        Parameters
        ----------
        filename : str
            A string for output text filename.
        delimiter : str, optional
            String or character separating columns.
        fmt : str or sequence of strs, optional
            Format specifier(s) for requested elements. This should exclude
            Date/Time and coordinate fields.

        See also
        --------
        to_csv  Save records to comma-separated text file.

        TODO: Auto-generate filename
        """
        el_header = delimiter.join(self.elements)
        add_n = len(self.elements) - len(Query.elements)
        add_fmt = ['%g'] * add_n if fmt is None else list(fmt)
        el_fmt = Query.fmt + add_fmt

        if self.mdb_extract or self.data is None:
            data = self.extract()
        else:
            log.info('Skip MDB_EXTRACT.')
            data = self.data

        if data is not None:
            mkdirp(os.path.dirname(filename))
            np.savetxt(filename,
                       data,
                       delimiter=delimiter,
                       header=el_header,
                       fmt=el_fmt,
                       comments='')
            log.info('File saved: %s', filename)
예제 #3
0
파일: __init__.py 프로젝트: yaswant/ypylib
    def to_dump(self, filename):
        """Dump a pickle of the extracted array to the specified file.
        The array can be read back with `pickle.load()` or `numpy.load()`.

        Parameters
        ----------
        filename : str
            A string for output dump filename.

        """
        if self.mdb_extract or self.data is None:
            data = self.extract()
        else:
            log.info('Skip MDB_EXTRACT.')
            data = self.data

        if data is not None:
            mkdirp(os.path.dirname(filename))
            data.dump(filename)
            log.info('File saved: %s', filename)
예제 #4
0
파일: examples.py 프로젝트: yaswant/ypylib
def plot_sataod_arabian_peninsula():
    """Plot SATAOD over the Arabian Peninsula."""
    from ypylib.utils import seqdate, log
    save_dir = os.path.expandvars('$SCRATCH/dust/20150820-20150920')
    for date in seqdate('2015-08-20', '2015-09-20',
                        in_fmt='%Y-%m-%d', out_fmt='%Y%m%d'):
        log.info(date)

        plt = plot_sataod(
            AREA=['38N', '12.5N', '34E', '67E'],
            START='/'.join([date, '0000Z']), STOP='/'.join([date, '2359Z']),
            plt_type='scatter', markersize=5,
            vmin=0, vmax=2,
            gspacing=(5, 5),
            map_res='l',
            drawcountries=True,
            title='MODIS aerosol optical depth (DT+DB): ' + date,
            cb_on=True, cb_title='AOD at 550nm []')
        plt.savefig('/'.join([save_dir, 'SATAOD_' + date + '.png']))
        plt.close()
예제 #5
0
파일: __init__.py 프로젝트: yaswant/ypylib
    def plot(self,
             element,
             index=None,
             fix_unknown=False,
             show=False,
             valid_min=None,
             valid_max=None,
             **kw):
        """Plot requested data on a cylindrical map.

        Parameters
        ----------
        element : str
            A string specifying the field to show on map. Usually one from the
            request elements.
        index : int
            index of second dimension when retrieving multi-dim array
            eg, if extracted field is (N, d), where N is number of records
            and d is number of wavelengths then index=1 will plot the field
            corresponding to the second wavelength, and so on...
        show : bool, optional
            True displays the plot (default is False which return a pyplot
            object)
        valid_min : real
            Valid minimum physical value in the array. Setting this will mask
            any values < valid_min
        valid_max : real
            Valid maximim physical value in the array. Setting this will mask
            any values > valid_max

        Keywords:
            See ypylib.XYZ.mapdata() keyword parameters for adjusting plot
            style.

        Returns
        -------
        matplotlib.pyplot : object when ``show=False``

        """
        # extract data from metdb
        if self.mdb_extract is False and self.data is not None:
            data = self.data
            log.info('Skip MDB_EXTRACT.')
        else:
            data = self.extract(fix_unknown=fix_unknown)
        if data is None:
            return

        # show data on map
        host = ['[{}]'.format(self.hostname), ''][self.hostname is None]

        if isinstance(element, str) is False:
            log.warning('ELEMENT should be a string, but given\n%s', element)
            return

        if index is None or len(data[element].shape) == 1:
            plt_arr = data[element]
            element_str = element
        else:
            plt_arr = data[element][:, index]
            element_str = '{} [{}]'.format(element, str(index))

        # vmin = kw.get('vmin', plt_arr.min())
        # vmax = kw.get('vmax', plt_arr.max())
        vmin = [valid_min, plt_arr.min()][valid_min is None]
        vmax = [valid_max, plt_arr.max()][valid_max is None]

        if np.ma.is_masked(vmin) and np.ma.is_masked(vmax):
            log.warning('No valid data points to plot.')
            return

        if len(plt_arr.shape) > 1:
            log.warning('Cant decide which array to plot,')
            log.info('Please give me an index value (e.g. index=1).')
            return

        w = (plt_arr >= vmin) & (plt_arr <= vmax)
        if sum(w) == 0:
            log.warning('Number of constrained data points = 0. Abort plot.')
            return

        xyz = XYZ(data['LNGD'][w], data['LTTD'][w], plt_arr[w])

        # w = (data[element] >= vmin) & (data[element] <= vmax)
        # xyz = XYZ(data['LNGD'][w], data['LTTD'][w], data[element][w])

        # update plot title
        title = kw.get(
            'title', '{}:{} {}\n{}-{}'.format(self.subtype, element_str, host,
                                              self.start, self.stop))
        kw.update({'title': title})

        # print(self.extent)
        if self.area:
            kw.update({'limit': self.limit})

        # warnings.simplefilter("ignore", UserWarning)
        res = xyz.mapdata(**kw)

        if show:
            res.show()
        else:
            return res
예제 #6
0
파일: __init__.py 프로젝트: yaswant/ypylib
    def extract(self, verbose=False, fix_unknown=False):
        """Extract obs from MetDB.

        Parameters
        ----------
        verbose : bool
            increase verbosity
        fix_unknown : bool, optional
            Set data types for unknown elements e.g., merged back model fields
            to 32bit float.

        Returns
        -------
        numpy ndarray matching request

        """
        try:
            data = obs(Query.contact,
                       self.subtype,
                       self.keywords,
                       self.elements,
                       hostname=self.hostname)

        except ValueError as verr:
            if fix_unknown:
                elements = self.elements[len(Query.elements):]
                log.warning("Setting dtypes for %s as 'float'", elements)

                for e in elements:
                    self.set_element_dtype(e, 'float')
                data = obs(Query.contact,
                           self.subtype,
                           self.keywords,
                           self.elements,
                           hostname=self.hostname)
            else:
                log.error(
                    '%s\n** Hint for unknown elements: use '
                    'extract(fix_unknow=True) OR call '
                    'set_element_dtype(element, dtype) prior '
                    'to extract() to bypass this error **', verr)
                raise (verr)

        except IOError as err:
            if verbose:
                log.info('  %s:%s\n  %s - %s\n  %s', self.hostname, self.ddict,
                         self.start, self.stop, sorted(self.elements))
            raise (err)

        if self.constrain:
            # single field constrain
            # key = list(self.constrain.keys())[0]
            # value = list(self.constrain.values())[0]
            # data = data[data[key] == value]

            # iterate through all constained fields
            for key, val in self.constrain.items():
                data = data[data[key] == val]
            if len(data) == 0:
                log.error('Constrain results with no data.')
                print(self.constrain)
                return

        if self.keep:
            self.data = data

        return data
예제 #7
0
파일: geo.py 프로젝트: yaswant/ypylib
def plotx(filename,
          ax=None, cb_on=False, cb_bounds=None, cb_nticks=None, cb_unit='',
          cb_width=0.02, ccolor='w', coastline=True, cres='110m',
          dataset_path=None, draw_countries=False, dust_rgb=False,
          dust_quality=None, extent=None, figsize=(6, 6), gl_font=None,
          glw=0.5, list_all=False, MDI=None, projection=None, quick=False,
          satellite='MSG', save_fig=None, show_path=False, show_ticks=False,
          stride=(1, 1), tag_fig=None, tag_col='k', title=None, xglocs=None,
          yglocs=None, **kw):
    """Display 2D arrays from geostationary Slotstore file.

    Args:
        filename (str): Slotstore filename. An hdf5 file containing full-disc
            arrays of geostationary satellite or equivalent model data.
        ax (cartopy.mpl.geoaxes.GeoAxesSubplot, optional): Plot data on a
            specific geo axis.
        cb_on (bool, optional): Add colour bar to the plot.
        cb_bounds (array_like, optional): Specify discrete bounds for colorbar.
        cb_nticks (int, optional): Number of ticks to show in the colorbar.
        cb_unit (str, optional): Show data unit string on colorbar.
        cb_width (float, optional): Colour bar width.
        ccolor (str, optional): Coastline/boundary colour. Defaults to white.
        coastline (bool, optional): Show/hide coastlines. Defaults to True.
            Setting this to False will show the plot as a plain 2D array.
        cres (str, optional): Resolution of cartopy coastline/country boundary.
            Defaults to '110m'.  Accepted values are '10m', '50m', '110m'.
        dataset_path (str, optional): Full path to 2D array data in hdf5.
        draw_countries (bool, optional): Show country boundaries.
        dust_rgb (bool, optional): Plot Dust RGB, require BT at 3 SEVIRI IR
            window channels in the file. Note: dataset_path and dust_rgb
            keywords are mutually exclusive.
        dust_quality (int, optional): Mask plot based on dust confidence flag
            (value range: 1-7).
        extent (sequence, optional): Longitude and Latitude bounds to plot the
            data (lon0, lon1, lat0, lat1)
        figsize (tuple, optional): Figure size. Default is (6, 6)
        gl_font (dict, optional):  Font properties for grid labels default is
            {'family': 'monospace', 'size': 8, 'color': '#333333'}
        glw (float, optional): Width of grid lines.
        list_all (bool, optional): Show list of all available dataset in the
            file (no plot) and exit.
        MDI (number, optional): Missing Data Indicator.
        projection (cartopy crs, optional): Cartopy projection to use for
            mapping - one from the following
            Geostationary(), PlateCarree(), Mercator().
        quick (bool, optional): Quick plot. Equivalent to stride=(10, 10).
        satellite (str, optional): Satellite ID. Defaults to 'MSG'. Accepted
            satellite IDs are: 'GOES16', 'GOES-E', 'GOES17', 'GOES-W',
            'IODC'|'MSG_IODC', 'HIM8'.
        save_fig (str, optional): Save plot to a named file.
        show_path (bool, optional): Show filename and dataset path on plot.
        show_ticks (bool, optional): plot ticks and tick labels for non-mapped
            display.
        stride (tuple, optional): Skip pixels in x,y dimension, Default (1, 1)
            is to show at full resolution.
        tag_fig (str, optional): Add optional string to top left corner of
            figure. Useful for figures for articles.
        tag_col (str, optional): Colour of tag_fig text.
        title (str, optional): Figure title. Defaults to variable name from
            dataset_path (or 'DustRGB').
        xglocs (array_like, optional): Locations of x grid-lines.
        yglocs (array_like, optional): Locations of y grid-lines.
        **kw: accepted `imshow` keywords (see imshow).

    Returns:
        matplotlib.pyplot or None: plot object or None if figure saved to disc.

    Raises:
        NotImplementedError: If Projection is not one of the following
            Geostationary, PlateCarree, Mercator
        ValueError: If dataset_path is missing or incorrect or ambiguous.

    """
    import matplotlib.pyplot as plt
    import cartopy.feature as cfeature
    import cartopy.mpl.gridliner as cgrid
    from matplotlib import colors, ticker

    # defaults for MSG 0-deg service
    idx = 1  # index of datetime string in hdf filename
    c_lon = 0  # central geostationary longitude
    def_extent = (-80, 80, -80, 80)  # default map extent
    sat = satellite.upper()
    if sat in ('IODC', 'MSG_IODC'):
        # update defaults for IODC service
        idx = 2
        c_lon = 41.5
        def_extent = (-40, 120, -80, 80)
    if sat == 'HIM8':
        # update defaults for Himawari service
        c_lon = 140.7
        def_extent = (60, 220, -80, 80)
    if sat in ('GOES16', 'GOES-E'):
        c_lon = -75
        def_extent = (-155, 5, -80, 80)
    if sat == 'GOES15':
        c_lon = -135
        # def_extent = (-155, 5, -80, 80)
    if sat in ('GOES17', 'GOES-W'):
        c_lon = -137
        # def_extent = (-155, 5, -80, 80)

    h5 = h5Parse(filename)
    if list_all:
        h5.ls()
        return

    if quick:
        stride = (10, 10)

    apply_dust_quality = False
    if dust_quality:
        dconf = '/Product/GM/DustAOD/DustConfidence'
        try:
            dset = h5.get_data(dconf)
            dust_qual = dset[dconf][::-1, ::-1][::stride[0], ::stride[1]]
            apply_dust_quality = True
        except KeyError:
            log.warn('Dust_quality not available - filter wont be applied')

    if gl_font is None:
        gl_font = dict(family='monospace', size=8, color='#333333')

    # Get dust RGB array
    if dust_rgb and dataset_path is None:
        dataset_path = 'DustRGB'
        cb_on = False
        plot_array = get_dust_rgb(h5, stride=stride, satellite=satellite)

    elif dataset_path and dust_rgb is False:
        dset = h5.get_data(dataset_path)
        if len(list(dset.keys())) == 0:
            return
        plot_array = dset[dataset_path][::-1, ::-1][::stride[0], ::stride[1]]
        # print plot_array.dtype

        if plot_array.dtype in (
                np.int8, np.int16, np.intc, np.uint8, np.uint16, np.intp):
            MDI = [MDI, IMDI][MDI is None]
            plot_array = np.ma.masked_equal(plot_array, MDI)
            if apply_dust_quality:
                plot_array = np.ma.masked_less(dust_qual, dust_quality)
        else:
            MDI = [MDI, RMDI][MDI is None]
            plot_array[plot_array <= (MDI + RMDItol)] = np.nan
            if apply_dust_quality:
                plot_array = np.ma.where(
                    dust_qual >= dust_quality, plot_array, np.nan)

    elif dataset_path and dust_rgb:
        raise ValueError('dust_rgb must be False if dataset_path is given')
    else:
        raise ValueError(
            'Either dust_rgb or dataset_path must be specified.\n\n'
            '  msgview(filename, [dataset_path|dust_rgb=True], ..) OR\n'
            '  msgview(filename, list_all=True) to see all datasets.\n')

    # Get MSG datetime string from hdf5 filename
    msg_datetime = os.path.basename(filename).split('_')[idx]
    title_str = [msg_datetime, os.path.basename(dataset_path)]

    # Reassign 3-channel DustMask values for readable legend/title
    if title_str[1] in 'Dust':
        title_str[1] = 'DustMask'
        plot_array[plot_array < -0.5] = 0
        plot_array[plot_array == 300] = 1
        plot_array[plot_array == 400] = 2
        plot_array[plot_array == 500] = 3

    # Rename DustHeightError to DustPressureError
    if title_str[1] in 'DustHeightError':
        title_str[1] = 'DustPressureError'

    if title is None:
        title = '{}  {}'.format(title_str[0], title_str[1])

    # Start plot
    if ax:
        projection = ax.projection
    else:
        plt.figure(figsize=figsize)
        projection = [projection, ccrs.Geostationary()][projection is None]

    # Normalise colour based on discrete colour bounds (cb_bounds)?
    if cb_bounds:
        bounds = np.array(cb_bounds)
        norm = colors.BoundaryNorm(boundaries=bounds, ncolors=len(bounds))
    else:
        norm = None

    # combine plot_array and imshow keywords
    plot_array_kw = {
        'extent': geo_extent(satellite=satellite),
        'origin': 'upper',
        'norm': None,
        'interpolation': None}
    plot_array_kw.update(**kw)
    gridline_kw = dict(alpha=0.5, xlocs=xglocs, ylocs=yglocs, linestyle='-',
                       linewidth=glw)
    if coastline:
        if projection in (ccrs.PlateCarree(),
                          ccrs.PlateCarree(central_longitude=0),
                          ccrs.PlateCarree(central_longitude=180),
                          ccrs.Mercator(),
                          ccrs.Mercator(central_longitude=0),
                          ccrs.Mercator(central_longitude=180)):

            # Plot using rectangular projection
            if ax is None:
                ax = plt.axes(projection=projection)
            extent = [extent, def_extent][extent is None]
            ax.set_extent(extent, ccrs.PlateCarree())
            gl = ax.gridlines(draw_labels=True, **gridline_kw)
            gl.xlabels_top = False
            gl.ylabels_right = False
            gl.xformatter = cgrid.LONGITUDE_FORMATTER
            gl.yformatter = cgrid.LATITUDE_FORMATTER
            gl.xlabel_style, gl.ylabel_style = gl_font, gl_font
            im = ax.imshow(plot_array, transform=ccrs.Geostationary(c_lon),
                           **plot_array_kw)

        elif projection == ccrs.Geostationary():
            # Plot in Geostationary projection
            if ax is None:
                ax = plt.axes(projection=ccrs.Geostationary(c_lon))
            ax.set_global()
            gl = ax.gridlines(**gridline_kw)
            im = ax.imshow(plot_array, **plot_array_kw)

            if extent:
                ax.set_extent(extent, ccrs.PlateCarree())
        else:
            raise NotImplementedError(
                '{} projection not implemented.\n'
                'Please use one from the following:\n'
                '\tGeostationary\n\tPlateCarree or\n\tMercator\n'.format(
                    projection.__class__))

        ax.coastlines(resolution=cres, lw=0.5, color=ccolor)
    else:
        if extent:
            # TODO: implement geo-to-pixel for cut outs without map
            log.warning('Ignored extent. For geographic subsets please set '
                        'coastline=True.')
        ax_pos = [0.05, 0.1, 0.8, 0.8]
        if show_ticks:
            ax_pos = [0.1, 0.1, 0.8, 0.8]
        if ax is None:
            ax = plt.axes(ax_pos)

    # Add country borders
    if draw_countries:
        ax.add_feature(cfeature.BORDERS, lw=0.4, edgecolor=ccolor)

    pos = ax.get_position()

    # Tag a figure with additional string at top-left (useful for figure
    # panel numbering)
    if tag_fig:
        # title = '{} {}'.format(tag_fig, title)
        ax.text(0.01, 0.95, tag_fig, color=tag_col, fontsize=14,
                transform=ax.transAxes)

    # Draw title text
    ax.set_title(title, fontsize="13", loc='left')

    # Hide plot ticks and tick labels?
    if show_ticks is False:
        for ticx, ticy in list(
                zip(ax.xaxis.get_major_ticks(), ax.yaxis.get_major_ticks())):
            ticx.tick1On = ticx.tick2On = False
            ticx.label1On = ticx.label2On = False
            ticy.tick1On = ticy.tick2On = False
            ticy.label1On = ticy.label2On = False

    # Show image without coastline - simple 2D array imshow()
    if coastline is False:
        im = plt.imshow(plot_array, norm=norm, interpolation=None, **kw)
        ax.grid(lw=0.5, alpha=0.5)

    # Attach vertical colour bar
    if cb_on:
        cax = plt.axes([pos.x1, pos.y0, cb_width, pos.height])
        cb = plt.colorbar(mappable=im, cax=cax, format='%g')
        cb.ax.tick_params(direction='in')
        cb.ax.set_title('{}'.format(cb_unit))
        if cb_nticks:
            tick_locator = ticker.MaxNLocator(nbins=cb_nticks)
            cb.locator = tick_locator
            cb.update_ticks()
        if title_str[1] in 'DustMask':
            cb.ax.set_yticklabels(
                ['Dust', 'Ice cloud', 'Low cloud/\nSurface', 'Uncertain'],
                rotation='90', va='bottom')

    if show_path:
        # Show filename and HDF5 dataset path on plot
        textstr = '{}\n{}'.format(dataset_path, filename)
        plt.gcf().text(0.99, 0.01, textstr, fontsize=8, ha='right')

    if save_fig:
        # save figure as file to disk
        plt.savefig(save_fig)
        plt.close()
        log.info('%s saved.', save_fig)
    else:
        # return pyplot object
        return plt
예제 #8
0
파일: geo.py 프로젝트: yaswant/ypylib
    def __init__(self, satellite, channel_resolution=None,
                 apply_SEVIRI_grid_correction=False):
        """Define satellite-specifics.

        Args:
            satellite (str): Satellite ID. Defaults to 'MSG'.
            channel_resolution (str, optional): Used to indicate channels with
                atypical resolution.
            apply_SEVIRI_grid_correction (bool, optional): SEVIRI grid
                correction to be applied for MSG data prior to 6 Dec 2017.
        """
        self.satellite = satellite
        self.channel_resolution = channel_resolution
        self.apply_SEVIRI_grid_correction = apply_SEVIRI_grid_correction
        self.sweep = 'y'

        if self.satellite[:3].upper() in ('MSG', 'IOD'):
            if self.channel_resolution == 'HRV':
                self.cfac = -40927014
                self.lfac = 40927014
                self.nc = 11136
                self.nl = 11136
                self.coff = 5566
                self.loff = 5566
                correction_offset = 1.5
            else:
                self.cfac = -13642337
                self.lfac = 13642337
                self.nc = 3712
                self.nl = 3712
                self.coff = 1856
                self.loff = 1856
                correction_offset = 0.5

            if self.apply_SEVIRI_grid_correction is True:
                log.info("Applying SEVIRI grid correction")
                self.coff += correction_offset
                self.loff += correction_offset

            if satellite.upper() in ('MSG_IODC', 'IODC'):
                self.sub_lon = 41.5
            elif satellite == 'MSG_RSS':
                self.sub_lon = 9.5
            else:
                self.sub_lon = 0

            # Intermediate coords deltas
            self.dx = 2**16 / self.cfac
            self.dy = 2**16 / self.lfac

            self.req = REQ
            self.rpol = RPOL
            self.satellite_height = 35785831

        elif self.satellite.upper() == 'HIM8':
            self.cfac = 20466275
            self.lfac = -20466275
            self.nc = 5500
            self.nl = 5500
            self.coff = 2750.5
            self.loff = 2750.5

            self.sub_lon = 140.7

            # Intermediate coords deltas
            self.dx = 2**16 / self.cfac
            self.dy = 2**16 / self.lfac

            # WGS84 = different from MSG
            self.req = 6378137
            self.rpol = 6356752.3
            self.satellite_height = 35785831

        elif self.satellite.upper() in ('GOES16', 'GOES17'):
            self.nc = 5424
            self.nl = 5424
            self.coff = 2712.5
            self.loff = 2712.5

            if satellite.upper() == 'GOES16':
                self.sub_lon = -75.0
            elif satellite.upper() == 'GOES17':
                self.sub_lon = -137.0

            # Intermediate coords deltas
            self.dx = np.rad2deg(0.000056)
            self.dy = np.rad2deg(-0.000056)

            # WGS84 = different from MSG
            self.req = 6378137
            self.rpol = 6356752.3
            self.satellite_height = 35786023

            # 'sweep_angle_axis' (CF conventions 1.7)
            self.sweep = 'x'

        elif self.satellite.upper() == 'GOES15':
            self.cfac = 10216334
            self.lfac = -10216334
            self.nc = 2816
            self.nl = 2816
            self.coff = 1408.5
            self.loff = 1408.5

            # GOES West
            self.sub_lon = -135.0

            # Intermediate coords deltas
            self.dx = 2**16 / self.cfac
            self.dy = 2**16 / self.lfac

            # WGS84 = different from MSG
            self.req = 6378137
            self.rpol = 6356752.3
            self.satellite_height = 35785831