import numpy as np
from imageio import imread
from shapely.geometry import shape
from shapely.wkt import loads
from gbdxtools.auth import Auth
try:
import matplotlib.pyplot as plt
has_matplotlib = True
except ImportError:
has_matplotlib = False
class BrowseImage(object):
"""
Image class for fetching and spatially indexing an image's browse image (low res previews)
Args:
catalog_id (str): the catalog id for the browse image
bbox (list): the bounding box in WGS84 coords for spatial indexing
Returns:
BrowseImage (object)
"""
def __init__(self, catalog_id, bbox=None):
self._interface = Auth()
self.catalog_id = catalog_id
self._get_image()
self.metadata = self._get_metadata()
self.shape = self.image.shape
self.geom = self._get_geometry()
self.xmin, self.ymin, self.xmax, self.ymax = self.geom.bounds
self.cell_width = (self.xmax - self.xmin)/self.shape[1]
self.cell_height = (self.ymax - self.ymin)/self.shape[0]
self.bbox = bbox
if self.bbox is not None:
# find which cells intersect the bbox
bbox_xmin, bbox_ymin, bbox_xmax, bbox_ymax = self.bbox
window_xmin = int(np.floor((bbox_xmin - self.xmin)/self.cell_width))
window_xmax = int(np.ceil((bbox_xmax - self.xmin)/self.cell_width))
window_ymax = self.shape[0]-int(np.floor((bbox_ymin - self.ymin)/self.cell_height))
window_ymin = self.shape[0]-int(np.ceil((bbox_ymax - self.ymin)/self.cell_height))
self.window = ((window_ymin, window_ymax), (window_xmin, window_xmax))
else:
self.window = None
def _get_image(self):
url = 'https://api.discover.digitalglobe.com/show?id={}'.format(self.catalog_id)
self.image = imread(url)
def rgb(self):
return self.read()
def _get_metadata(self):
url = 'https://geobigdata.io/catalog/v2/record/{}'.format(self.catalog_id)
response = self._interface.gbdx_connection.get(url)
response.raise_for_status()
return response.json()
def _get_geometry(self):
if 'footprintWkt' in self.metadata['properties'].keys():
geom = loads(self.metadata['properties']['footprintWkt'])
elif 'geometry' in self.metadata.keys():
geom = shape(self.metadata['geometry'])
else:
raise ValueError("Invalid metadata returned by metadata service. Cannot create BrowseImage")
return geom
def read(self):
if self.window is None:
return self.image
else:
(miny, maxy), (minx, maxx) = self.window
return self.image[miny:maxy,minx:maxx,:]
def plot(self, w=10, h=10, title='', fontsize=24):
assert has_matplotlib, 'Matplotlib is required to plot images'
plt.figure(figsize=(w, h))
sp = plt.subplot(1, 1, 1)
plt.axis('off')
sp.set_title(title, fontsize=fontsize)
plt.imshow(self.rgb())
plt.show()
