def support_epsg_code(self, crs):
"""
Returns a list of supported EPSG codes.
"""
try:
get_projection_params(crs)
except ValueError:
return False
return True
def changeMapSection(self, index=0, only_kwargs=False):
"""
Change the current map section to one of the predefined regions.
"""
# Get the initial projection parameters from the tables in mss_settings.
current_map_key = self.cbChangeMapSection.currentText()
predefined_map_sections = config_loader(
dataset="predefined_map_sections")
current_map = predefined_map_sections.get(current_map_key, {
"CRS": current_map_key,
"map": {}
})
proj_params = get_projection_params(current_map["CRS"])
# Create a keyword arguments dictionary for basemap that contains
# the projection parameters.
kwargs = current_map["map"]
kwargs.update({
"CRS": current_map["CRS"],
"BBOX_UNITS": proj_params["bbox"],
"OPERATION_NAME": self.waypoints_model.name
})
kwargs.update(proj_params["basemap"])
if only_kwargs:
# Return kwargs dictionary and do NOT redraw the map.
return kwargs
logging.debug("switching to map section '%s' - '%s'", current_map_key,
kwargs)
self.mpl.canvas.redraw_map(kwargs)
self.mpl.navbar.clear_history()
def test_get_projection_params(self):
assert coordinate.get_projection_params("epsg:4839") == {
'basemap': {
'epsg': '4839'
},
'bbox': 'meter(10.5,51)'
}
with pytest.raises(ValueError):
coordinate.get_projection_params('auto2:42005')
with pytest.raises(ValueError):
coordinate.get_projection_params('auto:42001')
with pytest.raises(ValueError):
coordinate.get_projection_params('crs:84')
def plot_hsection(self,
data,
lats,
lons,
bbox=(-180, -90, 180, 90),
level=None,
figsize=(960, 640),
crs=None,
proj_params=None,
valid_time=None,
init_time=None,
style=None,
resolution=-1,
noframe=False,
show=False,
transparent=False):
"""
EPSG overrides proj_params!
"""
if proj_params is None:
proj_params = {"projection": "cyl"}
bbox_units = "latlon"
# Projection parameters from EPSG code.
if crs is not None:
proj_params, bbox_units = [
get_projection_params(crs)[_x] for _x in ("basemap", "bbox")
]
logging.debug("plotting data..")
# Check if required data is available.
self.data_units = self.driver.data_units.copy()
for datatype, dataitem, dataunit in self.required_datafields:
if dataitem not in data:
raise KeyError(f"required data field '{dataitem}' not found")
origunit = self.driver.data_units[dataitem]
if dataunit is not None:
data[dataitem] = convert_to(data[dataitem], origunit, dataunit)
self.data_units[dataitem] = dataunit
else:
logging.debug("Please add units to plot variables")
# Copy parameters to properties.
self.data = data
self.lats = lats
self.lons = lons
self.level = level
self.valid_time = valid_time
self.init_time = init_time
self.style = style
self.resolution = resolution
self.noframe = noframe
self.crs = crs
# Derive additional data fields and make the plot.
logging.debug("preparing additional data fields..")
self._prepare_datafields()
logging.debug("creating figure..")
dpi = 80
figsize = (figsize[0] / dpi), (figsize[1] / dpi)
facecolor = "white"
fig = mpl.figure.Figure(figsize=figsize, dpi=dpi, facecolor=facecolor)
logging.debug(
"\twith frame and legends" if not noframe else "\twithout frame")
if noframe:
ax = fig.add_axes([0.0, 0.0, 1.0, 1.0])
else:
ax = fig.add_axes([0.05, 0.05, 0.9, 0.88])
# The basemap instance is created with a fixed aspect ratio for framed
# plots; the aspect ratio is not fixed for frameless plots (standard
# WMS). This means that for WMS plots, the map will always fill the
# entire image area, no matter of whether this stretches or shears the
# map. This is the behaviour specified by the WMS standard (WMS Spec
# 1.1.1, Section 7.2.3.8):
# "The returned picture, regardless of its return format, shall have
# exactly the specified width and height in pixels. In the case where
# the aspect ratio of the BBOX and the ratio width/height are different,
# the WMS shall stretch the returned map so that the resulting pixels
# could themselves be rendered in the aspect ratio of the BBOX. In
# other words, it should be possible using this definition to request a
# map for a device whose output pixels are themselves non-square, or to
# stretch a map into an image area of a different aspect ratio."
# NOTE: While the MSUI always requests image sizes that match the aspect
# ratio, for instance the Metview 4 client does not (mr, 2011Dec16).
# Some additional code to store the last 20 coastlines in memory for quicker
# access.
key = repr((proj_params, bbox, bbox_units))
basemap_use_cache = getattr(mswms_settings, "basemap_use_cache", False)
basemap_request_size = getattr(mswms_settings, "basemap_request_size ",
200)
basemap_cache_size = getattr(mswms_settings, "basemap_cache_size", 20)
bm_params = {
"area_thresh": 1000.,
"ax": ax,
"fix_aspect": (not noframe)
}
bm_params.update(proj_params)
if bbox_units == "degree":
bm_params.update({
"llcrnrlon": bbox[0],
"llcrnrlat": bbox[1],
"urcrnrlon": bbox[2],
"urcrnrlat": bbox[3]
})
elif bbox_units.startswith("meter"):
# convert meters to degrees
try:
bm_p = basemap.Basemap(resolution=None, **bm_params)
except ValueError: # projection requires some extent
bm_p = basemap.Basemap(resolution=None,
width=1e7,
height=1e7,
**bm_params)
bm_center = [float(_x) for _x in bbox_units[6:-1].split(",")]
center_x, center_y = bm_p(*bm_center)
bbox_0, bbox_1 = bm_p(bbox[0] + center_x,
bbox[1] + center_y,
inverse=True)
bbox_2, bbox_3 = bm_p(bbox[2] + center_x,
bbox[3] + center_y,
inverse=True)
bm_params.update({
"llcrnrlon": bbox_0,
"llcrnrlat": bbox_1,
"urcrnrlon": bbox_2,
"urcrnrlat": bbox_3
})
elif bbox_units == "no":
pass
else:
raise ValueError(f"bbox_units '{bbox_units}' not known.")
if basemap_use_cache and key in BASEMAP_CACHE:
bm = basemap.Basemap(resolution=None, **bm_params)
(bm.resolution, bm.coastsegs, bm.coastpolygontypes,
bm.coastpolygons, bm.coastsegs, bm.landpolygons, bm.lakepolygons,
bm.cntrysegs) = BASEMAP_CACHE[key]
logging.debug("Loaded '%s' from basemap cache", key)
else:
bm = basemap.Basemap(resolution='l', **bm_params)
# read in countries manually, as those are laoded only on demand
bm.cntrysegs, _ = bm._readboundarydata("countries")
if basemap_use_cache:
BASEMAP_CACHE[key] = (bm.resolution, bm.coastsegs,
bm.coastpolygontypes, bm.coastpolygons,
bm.coastsegs, bm.landpolygons,
bm.lakepolygons, bm.cntrysegs)
if basemap_use_cache:
BASEMAP_REQUESTS.append(key)
BASEMAP_REQUESTS[:] = BASEMAP_REQUESTS[-basemap_request_size:]
if len(BASEMAP_CACHE) > basemap_cache_size:
useful = {}
for idx, key in enumerate(BASEMAP_REQUESTS):
useful[key] = useful.get(key, 0) + idx
least_useful = sorted([
(value, key) for key, value in useful.items()
])[:-basemap_cache_size]
for _, key in least_useful:
del BASEMAP_CACHE[key]
BASEMAP_REQUESTS[:] = [
_x for _x in BASEMAP_REQUESTS if key != _x
]
if self._plot_countries:
# Set up the map appearance.
try:
bm.drawcoastlines(color='0.25')
except ValueError as ex:
logging.error(
"Error in basemap/matplotlib call of drawcoastlines: %s",
ex)
bm.drawcountries(color='0.5')
bm.drawmapboundary(fill_color='white')
# zorder = 0 is necessary to paint over the filled continents with
# scatter() for drawing the flight tracks and trajectories.
# Curiously, plot() works fine without this setting, but scatter()
# doesn't.
bm.fillcontinents(color='0.98', lake_color='white', zorder=0)
self._draw_auto_graticule(bm)
if noframe:
ax.axis('off')
self.bm = bm # !! BETTER PASS EVERYTHING AS PARAMETERS?
self.fig = fig
self.shift_data()
self.mask_data()
self.lonmesh, self.latmesh = bm(*np.meshgrid(self.lons, self.lats))
self._plot_style()
# Set transparency for the output image.
if transparent:
fig.patch.set_alpha(0.)
# Return the image as png embedded in a StringIO stream.
canvas = FigureCanvas(fig)
output = io.BytesIO()
canvas.print_png(output)
if show:
logging.debug("saving figure to mpl_hsec.png ..")
canvas.print_png("mpl_hsec.png")
# Convert the image to an 8bit palette image with a significantly
# smaller file size (~factor 4, from RGBA to one 8bit value, plus the
# space to store the palette colours).
# NOTE: PIL at the current time can only create an adaptive palette for
# RGB images, hence alpha values are lost here. If transparency is
# requested, the figure face colour is stored as the "transparent"
# colour in the image. This works in most cases, but might lead to
# visible artefacts in some cases.
logging.debug("converting image to indexed palette.")
# Read the above stored png into a PIL image and create an adaptive
# colour palette.
output.seek(0) # necessary for PIL.Image.open()
palette_img = PIL.Image.open(output).convert(mode="RGB").convert(
"P", palette=PIL.Image.ADAPTIVE)
output = io.BytesIO()
if not transparent:
logging.debug("saving figure as non-transparent PNG.")
palette_img.save(
output,
format="PNG") # using optimize=True doesn't change much
else:
# If the image has a transparent background, we need to find the
# index of the background colour in the palette. See the
# documentation for PIL's ImagePalette module
# (http://www.pythonware.com/library/pil/handbook/imagepalette.htm). The
# idea is to create a 256 pixel image with the same colour palette
# as the original image and use it as a lookup-table. Converting the
# lut image back to RGB gives us a list of all colours in the
# palette. (Why doesn't PIL provide a method to directly access the
# colours in a palette??)
lut = palette_img.resize((256, 1))
lut.putdata(list(range(256)))
lut = [c[1] for c in lut.convert("RGB").getcolors()]
facecolor_rgb = list(
mpl.colors.hex2color(mpl.colors.cnames[facecolor]))
for i in [0, 1, 2]:
facecolor_rgb[i] = int(facecolor_rgb[i] * 255)
try:
facecolor_index = lut.index(tuple(facecolor_rgb))
logging.debug(
"saving figure as transparent PNG with transparency index %s.",
facecolor_index)
palette_img.save(output,
format="PNG",
transparency=facecolor_index)
except ValueError:
logging.debug(
"transparency requested but not possible, saving non-transparent instead"
)
palette_img.save(output, format="PNG")
logging.debug("returning figure..")
return output.getvalue()