Geopy Module in Python

Geopy module in python makes it easy for geocoding

1. PRESENTATION ON GEOPY PYTHON MODULE PRESENT BY: Sayam Baidar (02 ) Sijan Bhandari(04) Rabina Twayana(29) Date:13 Feb 2020 1

2. CONTENTS Python Module Introduction to GeoPy Installation of GeoPy Geocoding Vs Reverse Geocoding Commonly Used method in GeoPy Uses of GeoPy in Distance Calculation Accessing data in GeoPy Exception in GeoPy 2

3. Python Module A module is a file consisting of Python code. A module can define functions, classes and variables. A module can also include runnable code. A module is a file containing Python definitions and statements 3

4. Introduction to GeoPy G eopy is a python module that includes geocoders class for calling several geocoding web services such as: Open StreetMap Nominatim ESRI ArcGIS Google Geocoding API(V3) Bing Maps API Yandex OpenMapQuest NaviData GeoNames DeocodeFare et c 4

5. Contd…. Makes easy to locate : Co-ordinate Address Geographic location(Mountains , rivers etc ) Landmarks Cities Countries across the globe using geocoders and other data sources 5

6. Installation using pip pip is install by default if we are using python 2>=2.7.9 or python 3>=3.4 If not, then install pip or install latest python for windows which support pip from https ://www.python.org/ 6

7. To check installed pip version 7

8. geopy installation In command prompt run: pip install geopy 8

9. Geocoder A class for handling Geocoding and Reverse Geocoding Geocoders define at least a geocode() method and a reverse() method . Each geolocation service we might use, such as Google Maps, Bing Maps, or Nominatim etc , has its own class in geopy.geocoders Geocoder accepts any settings needed to interact with its service, e.g., an API key, during its initialization . An API key is a unique identifier used to authenticate a user, or developer to an API which allow communication with services. from geopy.geocoders import Nominatim geolocator = Nominatim ( user_agent =“ specify_your_app_name_here ”) 9

10. Geocoding Vs Reverse Geocoding Geocoding(Forward Geocoding) Reverse Geocoding The process of converting addresses (like a street address) into geographic coordinates (like latitude and longitude), The process of converting geographic coordinates into a human-readable address. Used to place markers on a map, or position the map. Used t o find the address corresponding to a set of coordinates: Uses geocode() method Uses reverse() method 10

11. Commonly used methods in geopy geocode() Syntax: geocode(query) where, query( str ) is address we wish to geocode r everse() Syntax: reverse(query) where query is coordinates( lat,long ) for which we wish to obtain human-readable addresses. Both method returns geopy.location.Location object 11

12. g eocode() method Resolves given address into pair of coordinates Output: Kathmandu University, KU road, Kuttal , Srikhandapur , Dhulikhel , काभ्रेपलाञ्चोक, Bagmati Pradesh, 09771, Nepal ( 27.61866315, 85.53822627738802) 12

13. How to get an API key for OpenMapQuest ? Signed-up first from https ://developer.mapquest.com Click on "Create a New Key" Filled in "App Name" Filled in "Callback URL“ Click on “Create app” Click on uparrow of app name Get API key for OpenMapQuest 13

14. Geocoding using API key Output: 27.6474649 85.3348047874904 Output using Nominatim : (27.61866315 , 85.53822627738802) 14

15. r everse() method Resolve pair of co-ordinates to an address . Output Kathmandu University, KU road, Kuttal , Srikhandapur , Dhulikhel , काभ्रेपलाञ्चोक, Bagmati Pradesh, 09771, Nepal ( 27.61866315, 85.53822627738802) 15

16. Distance Calculation GeoPy can calculate distance between two points . Mainly two t ypes of distance are calculated by GeoPy: Great Circle Distance Geodesic Distance 16

17. Great Circle Distance Great circle distance is the shortest distance between two points on the surface of a sphere Uses spherical model of the Earth to calculate the surface distance between two points. Syntax: great_circle (args1, args2) where args1=location1 co-ordinate value args2= location2 co-ordinate value 17

18. Output: 388.4096417472016 km 241.3465621689344 388409.6417472016 18

19. Geodesic Distance A geodesic is the shortest path between two points on a curved surface, analogous to a straight line on a plane surface Uses ellipsoidal model of the Earth to calculate shortest distance between two point on the surface of Earth . More accurate than great_circle distance default is WGS-84 ellipsoid which is most globally accurate Includes few other models in the distance.ELLIPSOIDS dictionary: GRS-80 GRS-67 Airy (1830) Intl 1924 Clarke (1880) 19

20. Syntax geodesic(args1, args2) Output 386.2061376343612 km 386.20613763557986 km 20

21. Data Class geopy.location.Location Access the properties address : return type- Unicode Location as a formatted string returned by the geocoder, depending on the service latitude : return type- float Location’s latitude l ongitude : return type –float Location’s longitude altitude : return type- float Location’s altitude. raw: return type- dict Location’s raw, unparsed geocoder response. 21

22. 22

23. Contd.. Class geopy.point.Point A geodetic point with latitude, longitude, and altitude. Latitude and longitude are floating point values in degrees, minutes, seconds. Altitude is a floating point value in kilometers. Points can be created in a number of ways ….. 23

24. Output 41 30m 0s S, 81 0m 0s W 41 30m 0s S, 81 0m 0s W 41 30m 0s S, 81 0m 0s W, 2.5km 23 26m 22s N, 23 27m 30s E, 33.796224km 3 26m 22s N, 23 27m 30s E 24

25. GeopyError Exception BaseException ConfigurationError GeocoderServiceError GeocoderNotFound Exception class Hierarchy in GeoPy 25

26. Exception In Python, all exceptions must be instances of a class that derives from BaseException , then Exception and the GeopyError Geopy -specific exceptions are all inherited from GeopyError . Three Exception class are inherited from GeopyError Class. They are ConfigurationError When instantiating a geocoder, the arguments given were invalid. GeocoderNotFound Caller requested the geocoder matching a string, e.g., "google" > GoogleV3, but no geocoder could be found . 26

27. Contd GeocoderServiceError There was an exception caused when calling the remote geocoding service, and no more specific exception could be raised by geopy. When calling geocoders’ geocode or reverse methods, this is the most generic exception that can be raised, and any non- geopy exception will be caught and turned into this. 27

28. GeocoderServiceError GeocoderInsufficientPrivileges GeocoderAuthenticationFailure GeocoderUnavailable GeocoderTimedOut GeocoderParseError GeocoderQueryError 28

29. EXCEPTION DESCRIPTION GeocoderQueryError Either geopy detected input that would cause a request to fail, or a request was made and the remote geocoding service responded that the request was bad GeocoderUnavailable when it was not possible to establish a connection to the remote geocoding service GeocoderParseError Geopy could not parse the service’s response. This is probably due to a bug in geopy . GeocoderInsufficientPrivileges The remote geocoding service refused to fulfill a request using the account credentials given. GeocoderAuthenticationFailure The remote geocoding service rejected the API key, geocoder instantiated with. GeocoderTimedOut The call to the geocoding service was aborted because no response has been received within the timeout argument .Some services are just consistently slow, and a higher timeout may be needed to use them. 29

30. 30 Output: 27.61866315 85.53822627738802 OR Error Service timed out

31. GeocoderQueryError 31

32. ConfigurationError 32

33. REFRENCES GeoPy’s documentation . (2017, February 2). Retrieved January 13, 2020, from GeoPy Stable : https://geopy.readthedocs.io/en/stable/ Python , 3.8.1. (2019, December 18). Retrieved January 7, 2020, from https ://www.python.org/downloads/ Reddy., G. C. (2019, September 1). Python Modules . Retrieved January 11, 2020, from Python Tutorials for Beginners: http://www.gcreddy.com/python/python-modules/

34. THANK YOU FOR YOUR ATTENTATION!!!!!! 34

35. ANY QUESTIONS? 35