Función get_map

README.rst

@@ -200,6 +200,16 @@ Prints:
     Gire a la izquierda por CALLE RIOS ROSAS
     Objetivo logrado
 
+
+Get static map image
+~~~~~~~~~~~~~~~~~~~~
+
+This function gets a static map centered on an address,
+as a png image.
+
+Please note this function is quite heavy on the server side, it should be used only for single uses. For an extensive use, please consider cached map tiles extraction
+(for an example on this use, please check the ``example_get_map`` in the notebooks directory.
+
 Running the tests
 -----------------
 

pycartociudad/__init__.py

@@ -9,3 +9,4 @@
 from .reverse_geocode import reverse_geocode
 from .get_location_info import get_location_info
 from .route_between_two_points import route_between_two_points
+from .get_map import get_map

pycartociudad/get_map.py

@@ -0,0 +1,176 @@
+"""
+Obtain static image map of an address 
+using cartociudad API
+"""
+
+import requests
+import urllib
+from PIL import Image
+from math import radians, cos, sin, asin, sqrt
+#import shutil
+
+import geocode
+
+def haversine(lon1: float, lat1: float, lon2: float, lat2: float) -> float:
+    """
+    Calculate the great circle distance between two points 
+    on the earth (specified in decimal degrees)
+    """
+    # convert decimal degrees to radians 
+    lon1, lat1, lon2, lat2 = map(radians, [lon1, lat1, lon2, lat2])
+
+    # haversine formula 
+    dlon = lon2 - lon1 
+    dlat = lat2 - lat1 
+    a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
+    c = 2 * asin(sqrt(a)) 
+    r = 6371 # Radius of earth in kilometers. Use 3956 for miles
+    return c * r
+
+def get_bounding_box(lat: float, lon: float, radiusKm: float, aspectRatio: float) -> list:
+    """
+    Creates the bbox centered on a point with coords (lat,lon)
+
+    Parameters
+    ----------
+    lat: float
+        central point latitude
+
+    lon: float
+        central point longitude
+
+    radiusKm: float
+        area covered by the map (from center to the sides)
+
+    aspectRatio: float
+        height/width of the map
+
+    Returns
+    -------
+    bbox: list of float
+        list of coordinates in EPSG 4326 representation:
+        [bottom lat, left long, upper lat, right long]
+
+    """
+
+    assert radiusKm > 0
+
+    delta = 0.5 # This is sort of a magic number ?
+    deltaLon = radiusKm * delta * haversine(lon, lat, lon+delta, lat) / 2000
+    deltaLat = radiusKm * delta * haversine(lon, lat, lon, lat+delta) / 2000
+    deltaLat = deltaLat * aspectRatio
+
+    bbox = [lat - deltaLat, # bottom lat
+            lon - deltaLon, # left lon
+            lat + deltaLat, # upper lat
+            lon + deltaLon] # right lon
+
+    bbox = ['{:.12f}'.format(x) for x in bbox]
+
+    return bbox
+
+def get_layer_img(url: str, searchContent: str) -> Image.Image:
+    qParams = urllib.parse.urlencode(searchContent)
+    """Helper function to download the layer image
+    """
+    # perform request
+    r = requests.get(url=url, params=qParams, stream=True)
+
+    # Get image from the API response
+    if r.status_code == 200:
+        r.raw.decode_content = True
+        layerImg = Image.open(r.raw)
+        r.close()
+
+    return layerImg
+
+
+def get_map(center: tuple, radius: float, 
+    height: float = 600, width: float = 800,
+    censalLayer: bool = False, 
+    postLayer: bool = False, 
+    cadastralLayer: bool = False) -> Image.Image:
+    """This function downloads a map from CartoCiudad API centered on
+    a geographical point and returns it as a PIL image.
+
+    Parameters
+    ----------
+    center : tuple of str
+        (latitude, longitude) coordinates to center the map
+
+    radius: float
+        Map coverage in kilometers
+
+    height: int
+        Returned map height in pixels (default 600)
+
+    width: int
+        Returned map width in pixels (default 800)
+
+    censalLayer: bool
+        Option to add the limit of censal sections and districts to the
+        base map; note that this layer may not be available at low zoom
+        levels
+
+    postLayer: bool
+        Option to add the limit of zip code areas to the base map; note
+        that this layer may not be available at low zoom levels
+
+    cadastralLayer: bool
+        Option to add cadastral information
+
+    Returns
+    -------
+    image :  PIL image of height x width pixels
+    """
+
+    # build query content
+    bbox = get_bounding_box(float(center[0]),
+                            float(center[1]),
+                            float(radius),
+                            float(height)/width)
+
+    url = 'http://www.ign.es/wms-inspire/ign-base'
+    searchContent = {'service': 'WMS',
+                     'version': '1.3.0',
+                     'request': 'GetMap',
+                     'format': 'image/png',
+                     'transparent': 'true',
+                     'layers': 'IGNBaseTodo',
+                     'styles': 'default',
+                     'exceptions': 'xml',
+                     'srs': 'EPSG:4326',
+                     'width': str(width),
+                     'height': str(height),
+                     'bbox': ','.join(bbox)
+                    }
+    bgLayerImg = get_layer_img(url, searchContent)
+
+    if postLayer:
+        url = 'http://www.ign.es/wms-inspire/ign-base'
+        searchContent = {'service': 'WMS',
+                         'version': '1.3.0',
+                         'request': 'GetMap',
+                         'format': 'image/png',
+                         'transparent': 'true',
+                         'layers': 'codigo-postal',
+                         'styles': 'codigopostal',
+                         'exceptions': 'xml',
+                         'srs': 'EPSG:4326',
+                         'width': str(width),
+                         'height': str(height),
+                         'bbox': ','.join(bbox)
+                        }
+        fgLayerImg = get_layer_img(url, searchContent)
+        bgLayerImg.paste(fgLayerImg, (0,0), fgLayerImg.convert('RGBA'))
+
+
+    ## Code to download image locally
+    #r.raw.decode_content = True
+
+    #with open('image_name.png', 'wb') as handler:
+    #    shutil.copyfileobj(r.raw, handler)
+    #del r
+
+    return bgLayerImg
+