def _magnetic_warp(x, y, decimal_year=2016.0):
"""Apply magnetic warp magic."""
gc_lat, gc_lon, gc_rad = convert([y, x, 0], GEODETIC_ABOVE_WGS84, GEOCENTRIC_SPHERICAL)
qd_lat, qd_lon = eval_qdlatlon(gc_lat, gc_lon, gc_rad, decimal_year)
return qd_lon, qd_lat
def main(args):
"""Parse arguments and run graticule creation."""
parser = argparse.ArgumentParser()
parser.add_argument("output", type=str, help="output vector data")
parser.add_argument("stepsize", type=int, help="degree step size")
parser.add_argument(
"--size_x", type=int, help="model raster x size", default=8192)
parser.add_argument(
"--size_y", type=int, help="model raster y size", default=4096)
parser.add_argument(
"--driver", type=str, help="output driver", default="ESRI Shapefile")
parsed = parser.parse_args(args)
output_file = parsed.output
stepsize = parsed.stepsize
size_x = parsed.size_x
size_y = parsed.size_y
fieldname = "dd"
elevation = 0
bounds = (-180., -90., 180., 90.)
left, bottom, right, top = bounds
pixel_x_size = (right - left) / float(size_x)
pixel_y_size = (top - bottom) / float(size_y)
affine = Affine.translation(left, top) * Affine.scale(
pixel_x_size, -pixel_y_size)
if os.path.isfile(output_file):
os.remove(output_file)
lons, lats = np.meshgrid(
np.linspace(left, right, size_x, endpoint=True),
np.linspace(top, bottom, size_y, endpoint=True)
)
# Geodetic coordinates with elevation above the WGS84 ellipsoid.
coord_gdt = np.empty((size_y, size_x, 3))
coord_gdt[:, :, 0] = lats
coord_gdt[:, :, 1] = lons
coord_gdt[:, :, 2] = elevation
decimal_year = np.empty((size_y, size_x))
decimal_year.fill(2016.1)
coord_gct = convert(coord_gdt, GEODETIC_ABOVE_WGS84, GEOCENTRIC_SPHERICAL)
qd_lat, qd_lon = eval_qdlatlon(
coord_gct[..., 0].ravel(), coord_gct[..., 1].ravel(),
coord_gct[..., 2].ravel(), decimal_year.ravel())
# Latitudes
lat = np.reshape(qd_lat, (size_y, size_x))
lat_lines = extract_contours(lat, bounds, stepsize, fieldname, 0)
# Longitudes
lon = np.reshape(qd_lon, (size_y, size_x))
lon_lines = extract_contours(
np.absolute(lon), bounds, stepsize, fieldname, 0)
meridians = extract_contours(lon, bounds, stepsize, fieldname, 0)
# for row in range(len(lon)):
# diff = lon[row][:-1]-lon[row][1:]
# step_idxes = np.argwhere(diff > 180.)
# if step_idxes:
# lon[row][np.argwhere(diff > 180.)[0]+1:] += 360.
# lon_lines = extract_contours(lon, bounds, stepsize, fieldname)
out_schema = dict(
geometry="LineString",
properties=dict(
degrees="int", direction="str", display="str", dd="float",
scalerank="int"))
with fiona.open(
output_file, "w", schema=out_schema, crs={'init': 'epsg:4326'},
driver=parsed.driver
) as dst:
for feature in lat_lines:
latitude = feature["properties"]["dd"]
lat_int = int(round(latitude))
direction = "N" if lat_int > 0 else "S"
display_lat = lat_int if lat_int > 0 else -lat_int
display = "%s %s" % (display_lat, direction)
if lat_int == 0:
direction = None
display = "0"
feature["properties"].update(
degrees=lat_int, direction=direction, display=display,
scalerank=None)
dst.write(feature)
for feature in _extract_longitudes(lon_lines, lon, affine):
dst.write(feature)
longitude = feature["properties"]["dd"]
lon_int = int(round(longitude))
direction = "W" if lon_int > 0 else "E"
display_lon = lon_int if lon_int > 0 else -lon_int
display = "%s %s" % (display_lon, direction)
if lon_int == 0:
direction = None
display = "0"
feature["properties"].update(
degrees=lon_int, direction=direction, display=display,
scalerank=None)
# if longitude > 180.:
# feature["properties"].update(dd=longitude-360.)
# dst.write(feature)
for feature in meridians:
longitude = feature["properties"]["dd"]
if longitude in [0, 180]:
feature["properties"].update(
degrees=0, direction=None, display="0", scalerank=None)
dst.write(feature)
