GeoPython Workshop Plan

Getting the Data

We will be using two vector files from Natural Earth.

• Admin 0 - Countries
• Populated Places (Simple)

Custom Python Expression Functions Use Cases

• Select by Expression

- Select all the capital cities with population greater than the average population (or user-defined number). Find out the average population first.

- Select points based on their UTM Zone?

- Select the country in the country layer that has the maximum number of populated places in the populated places layer.

• Field Calculator

(a) In the Populated Places attribute table, create a new field, 'hemisphere' which can be North or South depending on the latitude value. OR

(b) Use Nominatim's reverse geocoder to find the full address for that latitude longitude. Write a Python function uses the API. See Nominatim wiki and the example: http://nominatim.openstreetmap.org/reverse?format=xml&lat=52.5487429714954&lon=-1.81602098644987&zoom=18&addressdetails=1

• Get the value of the env variable and do something with it

- Get the layer_name or layer_id of the Countries layer using get_env(). (Write function to set a new variable, layer_colour, according to the user defined colour. Usage: set_env()) ?

• Label using Expression functions

- name | population surge in percentage | , | three letter country code