wradlib.georef.rect.get_radolan_grid

wradlib.georef.rect.get_radolan_grid(nrows=None, ncols=None, trig=False, wgs84=False)

Calculates x/y coordinates of radolan grid of the German Weather Service

Returns the x,y coordinates of the radolan grid positions (lower left corner of every pixel). The radolan grid is a polarstereographic projection, the projection information was taken from RADOLAN-RADVOR-OP Kompositformat_2.2.2 [DWD, 2009]

Coordinates for 900km x 900km grid

Coordinate

lon

lat

x

y

LowerLeft

3.5889E

46.9526N

-523.4622

-4658.645

LowerRight

14.6209E

47.0705N

376.5378

-4658.645

UpperRight

15.7208E

54.7405N

376.5378

-3758.645

UpperLeft

2.0715E

54.5877N

-523.4622

-3758.645

Coordinates for 1100km x 900km grid

Coordinate

lon

lat

x

y

LowerLeft

4.6759E

46.1929N

-443.4622

-4758.645

LowerRight

15.4801E

46.1827N

456.5378

-4758.645

UpperRight

17.1128E

55.5342N

456.5378

-3658.645

UpperLeft

3.0889E

55.5482N

-433.4622

-3658.645

Coordinates for 1500km x 1400km grid

Coordinate

lon

lat

x

y

LowerLeft

2.3419E

43.9336N

-673.4622

-5008.645

Parameters
  • nrows (int) – number of rows (460, 900 by default, 1100, 1500)

  • ncols (int) – number of columns (460, 900 by default, 1400)

  • trig (boolean) – if True, uses trigonometric formulas for calculation if False, uses osr spatial reference system to transform between projections trig is recommended to be False, however, the two ways of computation are expected to be equivalent.

  • wgs84 (boolean) – if True, output coordinates are in wgs84 lonlat format (default: False)

Returns

radolan_grid (numpy.ndarray) – Array of shape (rows, cols, 2) xy- or lonlat-grid.

Examples

>>> # using osr spatial reference transformation
>>> import wradlib.georef as georef  # noqa
>>> radolan_grid = georef.get_radolan_grid()
>>> print("{0}, ({1:.4f}, {2:.4f})".format(radolan_grid.shape, *radolan_grid[0,0,:]))  # noqa
(900, 900, 2), (-523.4622, -4658.6447)
>>> # using pure trigonometric transformations
>>> import wradlib.georef as georef
>>> radolan_grid = georef.get_radolan_grid(trig=True)
>>> print("{0}, ({1:.4f}, {2:.4f})".format(radolan_grid.shape, *radolan_grid[0,0,:]))  # noqa
(900, 900, 2), (-523.4622, -4658.6447)
>>> # using osr spatial reference transformation
>>> import wradlib.georef as georef
>>> radolan_grid = georef.get_radolan_grid(1500, 1400)
>>> print("{0}, ({1:.4f}, {2:.4f})".format(radolan_grid.shape, *radolan_grid[0,0,:]))  # noqa
(1500, 1400, 2), (-673.4622, -5008.6447)
>>> # using osr spatial reference transformation
>>> import wradlib.georef as georef
>>> radolan_grid = georef.get_radolan_grid(900, 900, wgs84=True)
>>> print("{0}, ({1:.4f}, {2:.4f})".format(radolan_grid.shape, *radolan_grid[0,0,:]))  # noqa
(900, 900, 2), (3.5889, 46.9526)

See Polar Stereographic Projection.

Raises

TypeError, ValueError