DOC: Avoid downloading .tif file (#2919)

* Avoid downloading .tif file

Simplify by using that rasterio can read directly from http. 

This also removes imports of requests and os.

* let rasterio handle the http

* pep 8

* pep8

Author: grinsted

doc/gallery/plot_rasterio.py

@@ -16,22 +16,16 @@
 original map projection (see :ref:`recipes.rasterio_rgb`).
 """
 
-import os
-import urllib.request
-
 import cartopy.crs as ccrs
 import matplotlib.pyplot as plt
 import numpy as np
 from rasterio.warp import transform
 
 import xarray as xr
 
-# Download the file from rasterio's repository
-url = 'https://github.com/mapbox/rasterio/raw/master/tests/data/RGB.byte.tif'
-urllib.request.urlretrieve(url, 'RGB.byte.tif')
-
 # Read the data
-da = xr.open_rasterio('RGB.byte.tif')
+url = 'https://github.com/mapbox/rasterio/raw/master/tests/data/RGB.byte.tif'
+da = xr.open_rasterio(url)
 
 # Compute the lon/lat coordinates with rasterio.warp.transform
 ny, nx = len(da['y']), len(da['x'])
@@ -54,6 +48,3 @@
                cmap='Greys_r', add_colorbar=False)
 ax.coastlines('10m', color='r')
 plt.show()
-
-# Delete the file
-os.remove('RGB.byte.tif')

doc/gallery/plot_rasterio_rgb.py

@@ -13,20 +13,14 @@
 transformation.
 """
 
-import os
-import urllib.request
-
 import cartopy.crs as ccrs
 import matplotlib.pyplot as plt
 
 import xarray as xr
 
-# Download the file from rasterio's repository
-url = 'https://github.com/mapbox/rasterio/raw/master/tests/data/RGB.byte.tif'
-urllib.request.urlretrieve(url, 'RGB.byte.tif')
-
 # Read the data
-da = xr.open_rasterio('RGB.byte.tif')
+url = 'https://github.com/mapbox/rasterio/raw/master/tests/data/RGB.byte.tif'
+da = xr.open_rasterio(url)
 
 # The data is in UTM projection. We have to set it manually until
 # https://github.com/SciTools/cartopy/issues/813 is implemented
@@ -37,6 +31,3 @@
 da.plot.imshow(ax=ax, rgb='band', transform=crs)
 ax.coastlines('10m', color='r')
 plt.show()
-
-# Delete the file
-os.remove('RGB.byte.tif')