Source code for cartopy.io.img_tiles

# Copyright Cartopy Contributors
#
# This file is part of Cartopy and is released under the LGPL license.
# See COPYING and COPYING.LESSER in the root of the repository for full
# licensing details.

"""
Implements image tile identification and fetching from various sources.


The Matplotlib interface can make use of tile objects (defined below) via the
:meth:`cartopy.mpl.geoaxes.GeoAxes.add_image` method. For example, to add a
:class:`MapQuest Open Aerial tileset <MapQuestOpenAerial>` to an existing axes
at zoom level 2, do ``ax.add_image(MapQuestOpenAerial(), 2)``. An example of
using tiles in this way can be found at the
:ref:`sphx_glr_gallery_scalar_data_eyja_volcano.py` example.

"""

from abc import ABCMeta, abstractmethod
import concurrent.futures
import io
import os
import warnings

from PIL import Image
import shapely.geometry as sgeom
import numpy as np

import cartopy
import cartopy.crs as ccrs


[docs]class GoogleWTS(metaclass=ABCMeta): """ Implement web tile retrieval using the Google WTS coordinate system. A "tile" in this class refers to the coordinates (x, y, z). The tiles can be saved to a cache directory using the cache parameter, so they are downloaded only once. If it is set to True, the default path stored in the cartopy.config dictionary is used. If it is set to a custom path, this path is used instead of the default one. If it is set to False (the default behavior), the tiles are downloaded each time. """ _MAX_THREADS = 24
[docs] def __init__(self, desired_tile_form='RGB', user_agent=f'CartoPy/{cartopy.__version__}', cache=False): self.imgs = [] self.crs = ccrs.Mercator.GOOGLE self.desired_tile_form = desired_tile_form self.user_agent = user_agent # some providers like osm need a user_agent in the request issue #1341 # osm may reject requests if there are too many of them, in which case # a change of user_agent may fix the issue. # Enable a cache mechanism when cache is equal to True or to a path. self._default_cache = False if cache is True: self._default_cache = True self.cache_path = cartopy.config["cache_dir"] elif cache is False: self.cache_path = None else: self.cache_path = cache self.cache = set({}) self._load_cache()
def image_for_domain(self, target_domain, target_z): tiles = [] def fetch_tile(tile): try: img, extent, origin = self.get_image(tile) except OSError: # Some services 404 for tiles that aren't supposed to be # there (e.g. out of range). raise img = np.array(img) x = np.linspace(extent[0], extent[1], img.shape[1]) y = np.linspace(extent[2], extent[3], img.shape[0]) return img, x, y, origin with concurrent.futures.ThreadPoolExecutor( max_workers=self._MAX_THREADS) as executor: futures = [] for tile in self.find_images(target_domain, target_z): futures.append(executor.submit(fetch_tile, tile)) for future in concurrent.futures.as_completed(futures): try: img, x, y, origin = future.result() tiles.append([img, x, y, origin]) except OSError: pass img, extent, origin = _merge_tiles(tiles) return img, extent, origin @property def _cache_dir(self): """Return the name of the cache directory""" return os.path.join( self.cache_path, self.__class__.__name__ ) def _load_cache(self): """Load the cache""" if self.cache_path is not None: cache_dir = self._cache_dir if not os.path.exists(cache_dir): os.makedirs(cache_dir) if self._default_cache: warnings.warn( 'Cartopy created the following directory to cache ' f'GoogleWTS tiles: {cache_dir}') self.cache = self.cache.union(set(os.listdir(cache_dir))) def _find_images(self, target_domain, target_z, start_tile=(0, 0, 0)): """Target domain is a shapely polygon in native coordinates.""" assert isinstance(target_z, int) and target_z >= 0, ('target_z must ' 'be an integer ' '>=0.') # Recursively drill down to the images at the target zoom. x0, x1, y0, y1 = self._tileextent(start_tile) domain = sgeom.box(x0, y0, x1, y1) if domain.intersects(target_domain): if start_tile[2] == target_z: yield start_tile else: for tile in self._subtiles(start_tile): yield from self._find_images(target_domain, target_z, start_tile=tile) find_images = _find_images def subtiles(self, x_y_z): x, y, z = x_y_z # Google tile specific (i.e. up->down). for xi in range(0, 2): for yi in range(0, 2): yield x * 2 + xi, y * 2 + yi, z + 1 _subtiles = subtiles def tile_bbox(self, x, y, z, y0_at_north_pole=True): """ Return the ``(x0, x1), (y0, y1)`` bounding box for the given x, y, z tile position. Parameters ---------- x The x tile coordinate in the Google tile numbering system. y The y tile coordinate in the Google tile numbering system. z The z tile coordinate in the Google tile numbering system. y0_at_north_pole: optional Boolean representing whether the numbering of the y coordinate starts at the north pole (as is the convention for Google tiles) or not (in which case it will start at the south pole, as is the convention for TMS). Defaults to True. """ n = 2 ** z assert 0 <= x <= (n - 1), \ f"Tile's x index is out of range. Upper limit {n}. Got {x}" assert 0 <= y <= (n - 1), \ f"Tile's y index is out of range. Upper limit {n}. Got {y}" x0, x1 = self.crs.x_limits y0, y1 = self.crs.y_limits # Compute the box height and width in native coordinates # for this zoom level. box_h = (y1 - y0) / n box_w = (x1 - x0) / n # Compute the native x & y extents of the tile. n_xs = x0 + (x + np.arange(0, 2, dtype=np.float64)) * box_w n_ys = y0 + (y + np.arange(0, 2, dtype=np.float64)) * box_h if y0_at_north_pole: n_ys = -1 * n_ys[::-1] return n_xs, n_ys def tileextent(self, x_y_z): """Return extent tuple ``(x0,x1,y0,y1)`` in Mercator coordinates.""" x, y, z = x_y_z x_lim, y_lim = self.tile_bbox(x, y, z, y0_at_north_pole=True) return tuple(x_lim) + tuple(y_lim) _tileextent = tileextent @abstractmethod def _image_url(self, tile): pass def get_image(self, tile): from urllib.request import urlopen, Request, HTTPError, URLError if self.cache_path is not None: filename = "_".join([str(i) for i in tile]) + ".npy" cached_file = os.path.join( self._cache_dir, filename ) else: filename = None cached_file = None if filename in self.cache: img = np.load(cached_file, allow_pickle=False) else: url = self._image_url(tile) try: request = Request(url, headers={"User-Agent": self.user_agent}) fh = urlopen(request) im_data = io.BytesIO(fh.read()) fh.close() img = Image.open(im_data) except (HTTPError, URLError) as err: print(err) img = Image.fromarray(np.full((256, 256, 3), (250, 250, 250), dtype=np.uint8)) img = img.convert(self.desired_tile_form) if self.cache_path is not None: np.save(cached_file, img, allow_pickle=False) self.cache.add(filename) return img, self.tileextent(tile), 'lower'
[docs]class GoogleTiles(GoogleWTS):
[docs] def __init__(self, desired_tile_form='RGB', style="street", url=('https://mts0.google.com/vt/lyrs={style}' '@177000000&hl=en&src=api&x={x}&y={y}&z={z}&s=G'), cache=False): """ Parameters ---------- desired_tile_form: optional Defaults to 'RGB'. style: optional The style for the Google Maps tiles. One of 'street', 'satellite', 'terrain', and 'only_streets'. Defaults to 'street'. url: optional URL pointing to a tile source and containing {x}, {y}, and {z}. Such as: ``'https://server.arcgisonline.com/ArcGIS/rest/services/\ World_Shaded_Relief/MapServer/tile/{z}/{y}/{x}.jpg'`` """ styles = ["street", "satellite", "terrain", "only_streets"] style = style.lower() self.url = url if style not in styles: raise ValueError( f"Invalid style {style!r}. Valid styles: {', '.join(styles)}") self.style = style # The 'satellite' and 'terrain' styles require pillow with a jpeg # decoder. if self.style in ["satellite", "terrain"] and \ not hasattr(Image.core, "jpeg_decoder") or \ not Image.core.jpeg_decoder: raise ValueError( f"The {self.style!r} style requires pillow with jpeg decoding " "support.") return super().__init__(desired_tile_form=desired_tile_form, cache=cache)
def _image_url(self, tile): style_dict = { "street": "m", "satellite": "s", "terrain": "t", "only_streets": "h"} url = self.url.format( style=style_dict[self.style], x=tile[0], X=tile[0], y=tile[1], Y=tile[1], z=tile[2], Z=tile[2]) return url
[docs]class MapQuestOSM(GoogleWTS): # https://developer.mapquest.com/web/products/open/map for terms of use # https://devblog.mapquest.com/2016/06/15/ # modernization-of-mapquest-results-in-changes-to-open-tile-access/ # this now requires a sign up to a plan def _image_url(self, tile): x, y, z = tile url = f'https://otile1.mqcdn.com/tiles/1.0.0/osm/{z}/{x}/{y}.jpg' mqdevurl = ('https://devblog.mapquest.com/2016/06/15/' 'modernization-of-mapquest-results-in-changes' '-to-open-tile-access/') warnings.warn(f'{url} will require a log in and and will likely' f' fail. see {mqdevurl} for more details.') return url
[docs]class MapQuestOpenAerial(GoogleWTS): # https://developer.mapquest.com/web/products/open/map for terms of use # The following attribution should be included in the resulting image: # "Portions Courtesy NASA/JPL-Caltech and U.S. Depart. of Agriculture, # Farm Service Agency" def _image_url(self, tile): x, y, z = tile return f'https://oatile1.mqcdn.com/tiles/1.0.0/sat/{z}/{x}/{y}.jpg'
[docs]class OSM(GoogleWTS): # https://operations.osmfoundation.org/policies/tiles/ for terms of use def _image_url(self, tile): x, y, z = tile return f'https://a.tile.openstreetmap.org/{z}/{x}/{y}.png'
[docs]class Stamen(GoogleWTS): """ Retrieves tiles from maps.stamen.com. Styles include ``terrain-background``, ``terrain``, ``toner`` and ``watercolor``. For a full reference on the styles available please see http://maps.stamen.com. Of particular note are the sub-styles that are made available (e.g. ``terrain`` and ``terrain-background``). To determine the name of the particular [sub-]style you want, follow the link on http://maps.stamen.com to your desired style and observe the style name in the URL. Your style name will be in the form of: ``http://maps.stamen.com/{STYLE_NAME}/#9/37/-122``. Except otherwise noted, the Stamen map tile sets are copyright Stamen Design, under a Creative Commons Attribution (CC BY 3.0) license. Please see the attribution notice at http://maps.stamen.com on how to attribute this imagery. """
[docs] def __init__(self, style='toner', desired_tile_form='RGB', cache=False): super().__init__(desired_tile_form=desired_tile_form, cache=cache) self.style = style
def _image_url(self, tile): x, y, z = tile return f'http://tile.stamen.com/{self.style}/{z}/{x}/{y}.png'
[docs]class StamenTerrain(Stamen): """ **DEPRECATED:** This class is deprecated. Please use ``Stamen('terrain-background')`` instead. Terrain tiles defined for the continental United States, and include land color and shaded hills. The land colors are a custom palette developed by Gem Spear for the National Atlas 1km land cover data set, which defines twenty-four land classifications including five kinds of forest, combinations of shrubs, grasses and crops, and a few tundras and wetlands. The colors are at their highest contrast when fully zoomed-out to the whole U.S., and they slowly fade out to pale off-white as you zoom in to leave room for foreground data and break up the weirdness of large areas of flat, dark green. References ---------- * http://mike.teczno.com/notes/osm-us-terrain-layer/background.html * http://maps.stamen.com/ * https://wiki.openstreetmap.org/wiki/List_of_OSM_based_Services * https://github.com/migurski/DEM-Tools """
[docs] def __init__(self, cache=False): warnings.warn( "The StamenTerrain class was deprecated in v0.17. " "Please use Stamen('terrain-background') instead.", DeprecationWarning, stacklevel=2) # NOTE: This subclass of Stamen exists for legacy reasons. # No further Stamen subclasses will be accepted as # they can easily be created in user code with Stamen(style_name). return super().__init__(style='terrain-background', cache=cache)
[docs]class MapboxTiles(GoogleWTS): """ Implement web tile retrieval from Mapbox. For terms of service, see https://www.mapbox.com/tos/. """
[docs] def __init__(self, access_token, map_id, cache=False): """ Set up a new Mapbox tiles instance. Access to Mapbox web services requires an access token and a map ID. See https://www.mapbox.com/api-documentation/ for details. Parameters ---------- access_token : str A valid Mapbox API access token. map_id : str An ID for a publicly accessible map (provided by Mapbox). This is the map whose tiles will be retrieved through this process and is specified through the Mapbox Styles API (https://docs.mapbox.com/api/maps/styles/) Examples:: map_id='streets-v11' map_id='outdoors-v11' map_id='satellite-v9' """ self.access_token = access_token self.map_id = map_id super().__init__(cache=cache)
def _image_url(self, tile): x, y, z = tile return (f'https://api.mapbox.com/styles/v1/mapbox/{self.map_id}/tiles' f'/{z}/{x}/{y}?access_token={self.access_token}')
[docs]class MapboxStyleTiles(GoogleWTS): """ Implement web tile retrieval from a user-defined Mapbox style. For more details on Mapbox styles, see https://www.mapbox.com/studio-manual/overview/map-styling/. For terms of service, see https://www.mapbox.com/tos/. """
[docs] def __init__(self, access_token, username, map_id, cache=False): """ Set up a new instance to retrieve tiles from a Mapbox style. Access to Mapbox web services requires an access token and a map ID. See https://www.mapbox.com/api-documentation/ for details. Parameters ---------- access_token A valid Mapbox API access token. username The username for the Mapbox user who defined the Mapbox style. map_id A map ID for a map defined by a Mapbox style. This is the map whose tiles will be retrieved through this process. Note that this style may be private and if your access token does not have permissions to view this style, then map tile retrieval will fail. """ self.access_token = access_token self.username = username self.map_id = map_id super().__init__(cache=cache)
def _image_url(self, tile): x, y, z = tile return (f'https://api.mapbox.com/styles/v1/{self.username}' f'/{self.map_id}/tiles/256/{z}/{x}/{y}' f'?access_token={self.access_token}')
[docs]class QuadtreeTiles(GoogleWTS): """ Implement web tile retrieval using the Microsoft WTS quadkey coordinate system. A "tile" in this class refers to a quadkey such as "1", "14" or "141" where the length of the quatree is the zoom level in Google Tile terms. """ def _image_url(self, tile): return ('http://ecn.dynamic.t1.tiles.virtualearth.net/comp/' f'CompositionHandler/{tile}?mkt=en-' 'gb&it=A,G,L&shading=hill&n=z') def tms_to_quadkey(self, tms, google=False): quadKey = "" x, y, z = tms # this algorithm works with google tiles, rather than tms, so convert # to those first. if not google: y = (2 ** z - 1) - y for i in range(z, 0, -1): digit = 0 mask = 1 << (i - 1) if (x & mask) != 0: digit += 1 if (y & mask) != 0: digit += 2 quadKey += str(digit) return quadKey def quadkey_to_tms(self, quadkey, google=False): # algorithm ported from # https://msdn.microsoft.com/en-us/library/bb259689.aspx assert isinstance(quadkey, str), 'quadkey must be a string' x = y = 0 z = len(quadkey) for i in range(z, 0, -1): mask = 1 << (i - 1) if quadkey[z - i] == '0': pass elif quadkey[z - i] == '1': x |= mask elif quadkey[z - i] == '2': y |= mask elif quadkey[z - i] == '3': x |= mask y |= mask else: raise ValueError(f'Invalid QuadKey digit sequence: {quadkey}') # the algorithm works to google tiles, so convert to tms if not google: y = (2 ** z - 1) - y return (x, y, z) def subtiles(self, quadkey): for i in range(4): yield quadkey + str(i) def tileextent(self, quadkey): x_y_z = self.quadkey_to_tms(quadkey, google=True) return GoogleWTS.tileextent(self, x_y_z) def find_images(self, target_domain, target_z, start_tile=None): """ Find all the quadtrees at the given target zoom, in the given target domain. target_z must be a value >= 1. """ if target_z == 0: raise ValueError('The empty quadtree cannot be returned.') if start_tile is None: start_tiles = ['0', '1', '2', '3'] else: start_tiles = [start_tile] for start_tile in start_tiles: start_tile = self.quadkey_to_tms(start_tile, google=True) for tile in GoogleWTS.find_images(self, target_domain, target_z, start_tile=start_tile): yield self.tms_to_quadkey(tile, google=True)
[docs]class OrdnanceSurvey(GoogleWTS): """ Implement web tile retrieval from Ordnance Survey map data. To use this tile image source you will need to obtain an API key from Ordnance Survey. For more details on Ordnance Survey layer styles, see https://apidocs.os.uk/docs/map-styles. For the API framework agreement, see https://developer.ordnancesurvey.co.uk/os-api-framework-agreement. """ # API Documentation: https://apidocs.os.uk/docs/os-maps-wmts
[docs] def __init__(self, apikey, layer='Road', desired_tile_form='RGB', cache=False): """ Parameters ---------- apikey: required The authentication key provided by OS to query the maps API layer: optional The style of the Ordnance Survey map tiles. One of 'Outdoor', 'Road', 'Light', 'Night', 'Leisure'. Defaults to 'Road'. Details about the style of layer can be found at: - https://apidocs.os.uk/docs/layer-information - https://apidocs.os.uk/docs/map-styles desired_tile_form: optional Defaults to 'RGB'. """ super().__init__(desired_tile_form=desired_tile_form, cache=cache) self.apikey = apikey if layer not in ['Outdoor', 'Road', 'Light', 'Night', 'Leisure']: raise ValueError(f'Invalid layer {layer}') self.layer = layer
def _image_url(self, tile): x, y, z = tile return ( f'https://api2.ordnancesurvey.co.uk/mapping_api/v1/service/wmts?' f'key={self.apikey}&height=256&width=256&version=1.0.0&' f'tilematrixSet=EPSG%3A3857&style=true&layer={self.layer}%203857&' f'SERVICE=WMTS&REQUEST=GetTile&format=image%2Fpng&' f'TileMatrix=EPSG%3A3857%3A{z}&TileRow={y}&TileCol={x}')
def _merge_tiles(tiles): """Return a single image, merging the given images.""" if not tiles: raise ValueError('A non-empty list of tiles should ' 'be provided to merge.') xset = [set(x) for i, x, y, _ in tiles] yset = [set(y) for i, x, y, _ in tiles] xs = xset[0] xs.update(*xset[1:]) ys = yset[0] ys.update(*yset[1:]) xs = sorted(xs) ys = sorted(ys) other_len = tiles[0][0].shape[2:] img = np.zeros((len(ys), len(xs)) + other_len, dtype=np.uint8) - 1 for tile_img, x, y, origin in tiles: y_first, y_last = y[0], y[-1] yi0, yi1 = np.where((y_first == ys) | (y_last == ys))[0] if origin == 'upper': yi0 = tile_img.shape[0] - yi0 - 1 yi1 = tile_img.shape[0] - yi1 - 1 start, stop, step = yi0, yi1, 1 if yi0 < yi1 else -1 if step == 1 and stop == img.shape[0] - 1: stop = None elif step == -1 and stop == 0: stop = None else: stop += step y_slice = slice(start, stop, step) xi0, xi1 = np.where((x[0] == xs) | (x[-1] == xs))[0] start, stop, step = xi0, xi1, 1 if xi0 < xi1 else -1 if step == 1 and stop == img.shape[1] - 1: stop = None elif step == -1 and stop == 0: stop = None else: stop += step x_slice = slice(start, stop, step) img_slice = (y_slice, x_slice, Ellipsis) if origin == 'lower': tile_img = tile_img[::-1, ::] img[img_slice] = tile_img return img, [min(xs), max(xs), min(ys), max(ys)], 'lower' class AzureMapsTiles(GoogleWTS): def __init__(self, subscription_key, tileset_id="microsoft.imagery", api_version="2.0", desired_tile_form='RGB', cache=False): """ Set up a new instance to retrieve tiles from Azure Maps. Access to Azure Maps REST API requires a subscription key. See https://docs.microsoft.com/en-us/azure/azure-maps/azure-maps-authentication#shared-key-authentication/ # noqa: E501 for details. Parameters ---------- subscription_key A valid Azure Maps subscription key. tileset_id A tileset ID for a map. See https://docs.microsoft.com/en-us/rest/api/maps/renderv2/getmaptilepreview#tilesetid # noqa: E501 for details. api_version API version to use. Defaults to 2.0 as recommended by Microsoft. """ super().__init__(desired_tile_form=desired_tile_form, cache=cache) self.subscription_key = subscription_key self.tileset_id = tileset_id self.api_version = api_version def _image_url(self, tile): x, y, z = tile return ( f'https://atlas.microsoft.com/map/tile?' f'api-version={self.api_version}&tilesetId={self.tileset_id}&' f'x={x}&y={y}&zoom={z}&subscription-key={self.subscription_key}')