Cartopy wmts KeyError issue : TileMatrixLimits - python-3.x

Question

Since a while, I am using the wmts function of cartopy but since last week this function does not works returning this error:
KeyError: 'TileMatrixLimits with tileMatrix "1" already exists'
The run code is coming from the cartopy web doc.
below the code:
import matplotlib.pyplot as plt
import cartopy.crs as ccrs
def main():
url = 'https://map1c.vis.earthdata.nasa.gov/wmts-geo/wmts.cgi'
layer = 'VIIRS_CityLights_2012'
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())
ax.add_wmts(url, layer)
ax.set_extent([-15, 25, 35, 60], crs=ccrs.PlateCarree())
ax.set_title('Suomi NPP Earth at night April/October 2012')
plt.show()
if __name__ == '__main__':
main()
I do not understand what is wrong.
Thank for help.

Answer 1

You can solve it commenting the lines 654 to 657 of (your Python dir)/Lib/site-packages/owslib/wmts.py which check the existence of the indexes in the static function from_elements of the TileMatrixSetLink class
Like this:
for limits_element in link_element.findall(path):
tml = TileMatrixLimits(limits_element)
if tml.tilematrix:
#if tml.tilematrix in tilematrixlimits:
# msg = ('TileMatrixLimits with tileMatrix "%s" '
# 'already exists' % tml.tilematrix)
# raise KeyError(msg)
tilematrixlimits[tml.tilematrix] = tml
links.append(TileMatrixSetLink(uri, tilematrixlimits))
For portability effects you can replace that function in your code before you use it
Like this:
import matplotlib.pyplot as plt
import cartopy.crs as ccrs
### START REPLACEMENT ###
from owslib.wmts import TileMatrixSetLink, TileMatrixLimits, _TILE_MATRIX_SET_TAG, _TILE_MATRIX_SET_LIMITS_TAG, _TILE_MATRIX_LIMITS_TAG
def custom_from_elements(link_elements):
links = []
for link_element in link_elements:
matrix_set_elements = link_element.findall(_TILE_MATRIX_SET_TAG)
if len(matrix_set_elements) == 0:
raise ValueError('Missing TileMatrixSet in %s' % link_element)
elif len(matrix_set_elements) > 1:
set_limits_elements = link_element.findall(
_TILE_MATRIX_SET_LIMITS_TAG)
if set_limits_elements:
raise ValueError('Multiple instances of TileMatrixSet'
' plus TileMatrixSetLimits in %s' %
link_element)
for matrix_set_element in matrix_set_elements:
uri = matrix_set_element.text.strip()
links.append(TileMatrixSetLink(uri))
else:
uri = matrix_set_elements[0].text.strip()
tilematrixlimits = {}
path = '%s/%s' % (_TILE_MATRIX_SET_LIMITS_TAG,
_TILE_MATRIX_LIMITS_TAG)
for limits_element in link_element.findall(path):
tml = TileMatrixLimits(limits_element)
if tml.tilematrix:
tilematrixlimits[tml.tilematrix] = tml
links.append(TileMatrixSetLink(uri, tilematrixlimits))
return links
TileMatrixSetLink.from_elements = custom_from_elements
### END REPLACEMENT ###
def main():
url = 'https://map1c.vis.earthdata.nasa.gov/wmts-geo/wmts.cgi'
layer = 'VIIRS_CityLights_2012'
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())
ax.add_wmts(url, layer)
ax.set_extent([-15, 25, 35, 60], crs=ccrs.PlateCarree())
ax.set_title('Suomi NPP Earth at night April/October 2012')
plt.show()
if __name__ == '__main__':
main()