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Use 'Google Maps Elevation Service' to get elevation data for any location on Earth. (Python recipe) by Aristotelis Stamatiadis
ActiveState Code (http://code.activestate.com/recipes/578239/)

The Google Maps Elevation Service provides a simple interface for getting elevation data for any location on Earth, including locations under the sea (where the elevation is negative).

The following function is based on the examples presented in the Elevation API web page: https://developers.google.com/maps/documentation/elevation/.

Before using the Elevation Service you must read the rather strict usage limits set by Google in the above web page, especially the term that stipulates that "the Elevation API may only be used in conjunction with displaying results on a Google map; using elevation data without displaying a map for which elevation data was requested is prohibited."

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import urllib.request
import json

def get_elevation(lat, lng, sensor=False):
    """
    Returns the elevation of a specific location on earth using the Google
    Maps API.

    @param lat (float): The latitude of the location in degrees. Latitudes can
    take any value between -90 and 90.
    @param lng (float): The longitude of the location in degrees. Longitudes
    can take any value between -180 and 180.
    @param sensor (boolean): This parameter is required by the Google maps API
    and indicates whether the application that requests the elevation data is
    using a sensor (such as a GPS device). Default value is 'False'.

    @return: A tuple (elevation, lat, lng, status):
      * elevation (float): The requested elevation in meters. If the location is
        on the sea floor the returned elevation has a negative value.
      * lat, lng (float): The latitude and longitude of the location (for testing
        purposes: must be equal to the input values).
      * status (str): Error code:
        "OK": the API request was successful.
        "INVALID_REQUEST": the API request was malformed.
        "OVER_QUERY_LIMIT": the requester has exceeded quota.
        "REQUEST_DENIED": the API did not complete the request, likely because
        of an invalid 'sensor' parameter.
        "UNKNOWN_ERROR": other error
      * If the error code 'status' is not 'OK' then all other members of the
        returned tuple are set to 'None'.

    @note: More information about the Google elevation API and its usage limits
    can be found in https://developers.google.com/maps/documentation/elevation/.
    
    @example:
    >>> round(get_elevation(-38.407, -25.297)[0], 2) == -3843.86
    True
    >>> round(get_elevation(37.32522, -104.98470)[0], 2) == 2934.24    
    True
    """
    ## build the url for the API call
    ELEVATION_BASE_URL = 'http://maps.google.com/maps/api/elevation/json'
    URL_PARAMS = "locations=%.7f,%.7f&sensor=%s" % (lat, lng, "true" if sensor else "false")
    url = ELEVATION_BASE_URL + "?" + URL_PARAMS

    ## make the call (ie. read the contents of the generated url) and decode the
    ## result (note: the result is in json format).
    with urllib.request.urlopen(url) as f:
        response = json.loads(f.read().decode())

    status = response["status"]
    if status == "OK":
        result = response["results"][0]
        elevation = float(result["elevation"])
        lat = float(result["location"]["lat"])
        lng = float(result["location"]["lng"])
    else:
        elevation = lat = lng = None
    return (elevation, lat, lng, status)

if __name__ == "__main__":
    import doctest
    doctest.testmod()
Tags: elevation, gis, google_maps