Geographical-Computing

GISC 420 T1 2022 (always under construction!)

Consolidated index of video content

Week 1 Introduction

These are a mix of videos from 2021 and 2022, depending on which seem most useful.

• Computing and interfaces (2021) 4m26s (this is a bit rambly…)
• Why we use conda environments (2022) 13m40s
• Checking conda is installed (2022) 1m09s
• Building the g420 environment (2022) 2m58s
• Running IDLE (2022) 3m40s
• Overview of week’s practical elements (2021) 4m50s

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Week 2 Functions and conditionals

Introduction and practical aspects

• Getting to the materials 2m02s
• Unpacking the notebook materials and getting started 1m34s
• Introducing jupyter notebooks 6m16s

Slides about functions

• Defining a function 7m38s
• Function parameters 2m55s

Slides about conditionals

These are from 2021, because I forgot to hit record this time around (oops)

• Conditionals and the flow of program execution
• Boolean expressions with True and False and and, or and not
• Evaluation of Boolean expressions
• if and else

Introducing geopandas

• Introducing geopandas 4m50s
• Opening a spatial dataset and a simple map 4m21s
• Mapping data: choropleth maps 5m10s
• Multipanel maps 1m22s

Projections in geopandas

• Dealing with projections 6m45s

The assignment

• Preamble materials 12m33s
• The assignment itself 3m18s

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Week 3 Iteration and sequences

Introduction

• Overview comments 1m32s

  Iteration

• while loops 8m01s
• for loops 3m24s
• Iteration notebook 2m39s

Sequences

• Sequences, introducing strings and lists 5m57s
• Slicing sequences 4m05s
• string methods 2m57s
• list methods 1m00s
• Immutable strings, mutable lists 4m17s
• Sequences notebooks 1m31s

The hangman program

• Playing hangman 6m15s
• Overview of the hangman code 10m03s

Overview of ASSIGNMENT 2

• The overall goal and the provided code 8m53s
• The assignment itself 5m31s

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Week 4 Dictionaries and data decoding

How dictionaries work

• Dictionaries and me (1m19s)
• Overview of dictionaries (2m30s)
• A silly example: Te Reo - English translation (2m25s)
• The basic features of dictionaries ()
• Inverting dictionaries to get the reverse lookup from values to keys (3m48s)

Two ways to use dictionaries: counting and memoizing

• Counting using a dictionary (9m23s)
• Memoizing a function using a dictionary (11m51s)
• cachetools (1m55s)

Overview of ASSIGNMENT 3

• The land resource inventory data (9m11s)
• An outline solution (8m17s)

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Week 5 geopandas as a GIS

These materials were recorded in 2020, but remain applicable this year.

• Overview
• Loading the data
• Buffering
• Centroids and other spatial properties
• Spatial transformation
• Spatial overlays and joins
• Dissolves and merges

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Week 6 Object orientation

• Introduction to OOP 7m45s
• A minimalist class that contains data 8m27s
• Copying an object with copy.copy() 1m35s
• Objects as more than data containers 6m11s Note: I seem to have cut the last 10s or so from that one, but you get the idea…
• How the class constructor imposes expectations on data 3m05s
• ‘Dunder’ methods (plus digression about self) 9m17s
• Adding specialised methods to our class 2m40s
• dataclass objects 3m25s
• Composing more complex classes from simple ones 8m14s Note: probably shouldn’t use a tuple of Points in case we might want the Polygon vertices to be mutable.

The mini-project and me rambling about some potential topics

Nothing to see here really…, but for completeness…

• Overview 2m26s
• Isochrones 4m21s
• Multitype Voronoi 2m15s
• Gerrymandering and zone design 6m09s
• Cartograms 2m49s
• Visibility graphs 1m42s
• Woven maps 5m23s

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Week 7 Random other stuff and working environments

• Introductory comments 1m18s

Trivia

• Indentation tricks 7m10s

Smart function signatures

• Default values 4m00s
• Arbitrary numbers of arguments 4m22s
• Keyword arguments 2m50s
• Putting it all together 3m06s

List comprehensions

• What they are 3m07s
• Two trivial reasons to use them 2m16s
• Performance… take 1, where I get flustered 2m43s
• Performance… take 2, which is not as bad… 1m31s
• map and comprehensions 6m21s

Importing modules

• Importing modules 6m21s

Working on a project with conda, git and VSCode

• conda environments… with more technical glitches 5m22s
• An overview of github 7m28s
• History on github and cloning a repo locally 6m41s
• VSCode and your project 9m45s

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Week 8 Web scraping

New! For 2021…

HTML and the web

• The web in general (6:03)
• A simple web page (8:31)
• A more complicated web page (5:38)
• Summing all that up (5:00)
• Query parameters in a URL (1:59)

Browser developer tools

• Way more complicated and browser developer tools (6:51)

Grabbing data and APIs

• Grabbing the AED locations data (11:01)
• APIs and why web scraping (8:11)

Web scraping

• The DOM (4:45)
• Introducing BeautifulSoup4 (8:10)
• Grabbing the data (7:13)
• Making a scraper (5:13)

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Week 9 Automating GIS with python

Some glitches at the start with getting that WFS layer into Q. And the sound is only OK, I’m afraid…

The python console and pyqgis

• The python console in QGIS and pyqgis the horror, the horror (7:51)
• Doing some odds and ends in the console (6:35)
• There is also an editor available… and why pyqgis is not very ‘pythonic’ (6:52)

(Try import this in a python console.)

Model designer

• Answer to a question about whether a simpler API would be possible in some other language (5:04)
• Model designer intro and the sequence of operations for the polygon Voronoi model (9:51)
• Automating that workflow… (6:17)
• Models and generated code (8:36)
• Some limitations of visual model builders (9:58)

Use code!

• Use code instead! (4:21)

Wrapping code in a model? No! Make a plugin

• Could you wrap code in a model? (2:57)
• Digression about GTFS and the no. 29 (3:55)
• Some example plugins (7:08)
• Reflections on sharing of avenue scripts and QGIS plugins, and final thoughts (7:34)