def add_world_ocean_basemap(self, target_resolution=[600, 600]):
""" Adds ESRI's Ocean Basemap to the map background.
Args
----
target_resolution (tuple or list): the resolution in pixels of the
basemap.
Note
----
This function required the following lines to be copy-pasted
into the file ogc_clients.py of the cartopy package, in order to
work:
** START COPY BELOW **
METERS_PER_UNIT = {
'urn:ogc:def:crs:EPSG::27700': 1,
'urn:ogc:def:crs:EPSG::900913': 1,
'urn:ogc:def:crs:EPSG:6.18.3:3857': 1,
'urn:ogc:def:crs:EPSG::4326': _WGS84_METERS_PER_UNIT,
'urn:ogc:def:crs:OGC:1.3:CRS84': _WGS84_METERS_PER_UNIT,
'urn:ogc:def:crs:EPSG::3031': 1,
'urn:ogc:def:crs:EPSG::3413': 1
}
_URN_TO_CRS = collections.OrderedDict([
('urn:ogc:def:crs:OGC:1.3:CRS84', ccrs.PlateCarree()),
('urn:ogc:def:crs:EPSG::4326', ccrs.PlateCarree()),
('urn:ogc:def:crs:EPSG::900913', ccrs.GOOGLE_MERCATOR),
('urn:ogc:def:crs:EPSG:6.18.3:3857', ccrs.GOOGLE_MERCATOR),
('urn:ogc:def:crs:EPSG::27700', ccrs.OSGB()),
('urn:ogc:def:crs:EPSG::3031', ccrs.Stereographic(
central_latitude=-90,
true_scale_latitude=-71)),
('urn:ogc:def:crs:EPSG::3413', ccrs.Stereographic(
central_longitude=-45,
central_latitude=90,
true_scale_latitude=70))
])
** STOP COPY ABOVE **
"""
# Web map server
wmts = 'http://services.arcgisonline.com/arcgis/rest/services/Ocean/'
wmts += 'World_Ocean_Base/MapServer/WMTS/1.0.0/WMTSCapabilities.xml'
wmts = WMTSRasterSource(wmts, 'Ocean_World_Ocean_Base')
proj = self.projection
extent = self.get_extent()
img = wmts.fetch_raster(proj, extent, target_resolution)
self.imshow(img[0][0], extent=img[0][1], transform=proj,
origin='upper', interpolation='bicubic')
def test_wmts_tile_caching():
image_cache = WMTSRasterSource._shared_image_cache
image_cache.clear()
assert len(image_cache) == 0
url = 'http://map1c.vis.earthdata.nasa.gov/wmts-geo/wmts.cgi'
wmts = WebMapTileService(url)
layer_name = 'MODIS_Terra_CorrectedReflectance_TrueColor'
source = WMTSRasterSource(wmts, layer_name)
gettile_counter = CallCounter(wmts, 'gettile')
crs = ccrs.PlateCarree()
extent = (-180, 180, -90, 90)
resolution = (20, 10)
with gettile_counter:
source.fetch_raster(crs, extent, resolution)
n_tiles = 2
assert gettile_counter.count == n_tiles, ('Too many tile requests - '
'expected {}, got {}.'.format(
n_tiles,
gettile_counter.count)
)
gc.collect()
assert len(image_cache) == 1
assert len(image_cache[wmts]) == 1
tiles_key = (layer_name, '0')
assert len(image_cache[wmts][tiles_key]) == n_tiles
# Second time around we shouldn't request any more tiles so the
# call count will stay the same.
with gettile_counter:
source.fetch_raster(crs, extent, resolution)
assert gettile_counter.count == n_tiles, ('Too many tile requests - '
'expected {}, got {}.'.format(
n_tiles,
gettile_counter.count)
)
gc.collect()
assert len(image_cache) == 1
assert len(image_cache[wmts]) == 1
tiles_key = (layer_name, '0')
assert len(image_cache[wmts][tiles_key]) == n_tiles
# Once there are no live references the weak-ref cache should clear.
del source, wmts, gettile_counter
gc.collect()
assert len(image_cache) == 0
def test_wmts_tile_caching():
image_cache = WMTSRasterSource._shared_image_cache
image_cache.clear()
assert len(image_cache) == 0
url = 'https://map1c.vis.earthdata.nasa.gov/wmts-geo/wmts.cgi'
wmts = WebMapTileService(url)
layer_name = 'MODIS_Terra_CorrectedReflectance_TrueColor'
source = WMTSRasterSource(wmts, layer_name)
gettile_counter = CallCounter(wmts, 'gettile')
crs = ccrs.PlateCarree()
extent = (-180, 180, -90, 90)
resolution = (20, 10)
with gettile_counter:
source.fetch_raster(crs, extent, resolution)
n_tiles = 2
assert gettile_counter.count == n_tiles, ('Too many tile requests - '
'expected {}, got {}.'.format(
n_tiles,
gettile_counter.count)
)
gc.collect()
assert len(image_cache) == 1
assert len(image_cache[wmts]) == 1
tiles_key = (layer_name, '0')
assert len(image_cache[wmts][tiles_key]) == n_tiles
# Second time around we shouldn't request any more tiles so the
# call count will stay the same.
with gettile_counter:
source.fetch_raster(crs, extent, resolution)
assert gettile_counter.count == n_tiles, ('Too many tile requests - '
'expected {}, got {}.'.format(
n_tiles,
gettile_counter.count)
)
gc.collect()
assert len(image_cache) == 1
assert len(image_cache[wmts]) == 1
tiles_key = (layer_name, '0')
assert len(image_cache[wmts][tiles_key]) == n_tiles
# Once there are no live references the weak-ref cache should clear.
del source, wmts, gettile_counter
gc.collect()
assert len(image_cache) == 0
def test_wmts_tile_caching():
image_cache = WMTSRasterSource._shared_image_cache
image_cache.clear()
assert len(image_cache) == 0
url = 'https://map1c.vis.earthdata.nasa.gov/wmts-geo/wmts.cgi'
wmts = WebMapTileService(url)
layer_name = 'MODIS_Terra_CorrectedReflectance_TrueColor'
source = WMTSRasterSource(wmts, layer_name)
crs = ccrs.PlateCarree()
extent = (-180, 180, -90, 90)
resolution = (20, 10)
n_tiles = 2
with mock.patch.object(wmts, 'gettile',
wraps=wmts.gettile) as gettile_counter:
source.fetch_raster(crs, extent, resolution)
assert gettile_counter.call_count == n_tiles, (
f'Too many tile requests - expected {n_tiles}, got '
f'{gettile_counter.call_count}.')
del gettile_counter
gc.collect()
assert len(image_cache) == 1
assert len(image_cache[wmts]) == 1
tiles_key = (layer_name, '0')
assert len(image_cache[wmts][tiles_key]) == n_tiles
# Second time around we shouldn't request any more tiles.
with mock.patch.object(wmts, 'gettile',
wraps=wmts.gettile) as gettile_counter:
source.fetch_raster(crs, extent, resolution)
gettile_counter.assert_not_called()
del gettile_counter
gc.collect()
assert len(image_cache) == 1
assert len(image_cache[wmts]) == 1
tiles_key = (layer_name, '0')
assert len(image_cache[wmts][tiles_key]) == n_tiles
# Once there are no live references the weak-ref cache should clear.
del source, wmts
gc.collect()
assert len(image_cache) == 0