QGIS Python Programming Cookbook

Visualizing data on a globe

Visualizing data in 3D with WebGL

Using OpenStreetMap's points of interest in QGIS

Creating HTML labels in QGIS

Using a different status bar CRS than the map

Calculating length for all selected lines

Creating dynamic forms in QGIS

Using expression-based labels

Generating points along a line

Using the __geo_interface__ protocol

Using alpha values to show data density

Using generators for layer queries

Using NULL values in PyQGIS

Creating a layer style file

Rendering map layers based on rules

Adding a layer to geojson.io

Creating tiles from a QGIS map

Introduction

Chapter 9. Other Tips and Tricks

Image change detection

Geolocating photos on the map

Computing road slope using elevation data

Collecting field data

Creating a dot density map

Creating a heat map

Performing nearest neighbor analysis

Finding the least cost path

Creating a mapbook

Tracking a GPS

Routing along streets

Performing network analysis

Creating raster footprints

Geocoding addresses

Creating an NDVI

Introduction

Chapter 8. QGIS Workflows

Keeping dialogs on top

Stepping the user through a wizard

Creating tabs

Creating checkboxes

Creating radio buttons

Creating a combobox

Creating a file input dialog

Creating a simple text input dialog

Displaying a progress bar

Creating an error dialog

Creating a warning dialog

Creating a simple message dialog

Using log files

Introduction

Chapter 7. Interacting with the User

Loading a map from a project

Saving a map to a project

Adding a world file to a map image

Adding a table to the map

Adding a grid to the map

Adding a custom shape to the map

Adding a legend to the map

Adding a logo to the map

Adding a north arrow to the map

Adding a scale bar to the map

Adding labels to a map for printing

Using the map composer

Creating the simplest map renderer

Introduction

Chapter 6. Composing Static Maps

Creating a mouse coordinate tracking tool

Building a custom selection tool

Using a map tool to draw polygons or lines on the canvas

Using a map tool to draw points on the canvas

Adding standard map tools to the canvas

Changing map layer transparency

Labeling features

Adding real-time weather data from OpenWeatherMap

Using the Bing aerial image service

Using the OpenStreetMap service

Using pie charts for symbols

Using SVG for layer symbols

Setting scale-based visibility for a layer

Navigating to a map bookmark

Creating a map bookmark

Creating a categorized vector layer symbol

Creating a graduated vector layer symbol renderer

Using icons as vector layer symbols

Creating a complex vector layer symbol

Rendering a single band raster using a color ramp algorithm

Symbolizing a vector layer

Iterating over layers

Changing the map units

Accessing the map canvas

Introduction

Chapter 5. Creating Dynamic Maps

Clipping a raster using a shapefile

Georeferencing a raster from control points

Converting a raster to a vector

Classifying a raster

Creating a KML image overlay for a raster

Converting a map coordinate to a pixel location

Converting a pixel location to a map coordinate

Creating pyramids for a raster

Converting a TIFF image to a JPEG image

Mosaicing rasters

Counting the unique values in a raster

Resampling raster resolution

Creating a common extent for rasters

Adding elevation data to line vertices using a digital elevation model

Sampling a raster dataset using a regular grid

Creating vector contours from elevation data

Creating an elevation hillshade

Reprojecting a raster

Querying the value of a raster at a specified point

Swapping raster bands

Counting raster bands

Obtaining the width and height of a raster

Getting the cell size of a raster layer

Loading a raster layer

Introduction

Chapter 4. Using Raster Data

Rasterizing a vector layer

Performing a union on vector shapes

Dissolving vector shapes

Generalizing a vector layer

Splitting a shapefile

Merging shapefiles

Converting a shapefile to KML

Reprojecting a vector layer

Deleting a vector layer attribute

Deleting a vector layer feature

Changing a vector layer feature's attribute

Moving vector layer geometry

Joining a shapefile attribute table to a CSV file

Adding a field to a vector layer

Adding a set of attributes to a vector layer

Adding a polygon feature to a vector layer

Adding a line feature to a vector layer

Adding a point feature to a vector layer

Creating a vector layer in memory

Introduction

Chapter 3. Editing Vector Data

Loading data from a spreadsheet

Calculating the bearing of a line

Creating a spatial index

Calculating the area of a polygon

Measuring the distance along a line sample

Measuring the distance between two points

Buffering a feature intermediate

Filtering a layer by attributes

Filtering a layer by geometry

Examining vector layer attributes

Examining vector layer features

Loading a vector layer from a spatial database

Loading a vector layer from a file sample

Introduction

Chapter 2. Querying Vector Data

Accessing the script path from within your script

Storing and reading project preferences

Storing and reading global preferences

Creating a standalone application

Distributing a plugin

Creating a QGIS plugin

Navigating the PyQGIS API

Debugging QGIS Python scripts

Setting up your QGIS IDE

Using the Python ScriptRunner plugin

Using the QGIS Python console for interactive control

Installing QGIS for development

Introduction

Chapter 1. Automating QGIS

Customer support

Reader feedback

Conventions

Sections

Who this book is for

What you need for this book

What this book covers

Preface

Support files eBooks discount offers and more

www.PacktPub.com

About the Reviewers

About the Author

Credits

QGIS Python Programming Cookbook

coverpage

coverpage

QGIS Python Programming Cookbook

Credits

About the Author

About the Reviewers

www.PacktPub.com

Support files eBooks discount offers and more

Preface

What this book covers

What you need for this book

Who this book is for

Sections

Conventions

Reader feedback

Customer support

Chapter 1. Automating QGIS

Introduction

Installing QGIS for development

Using the QGIS Python console for interactive control

Using the Python ScriptRunner plugin

Setting up your QGIS IDE

Debugging QGIS Python scripts

Navigating the PyQGIS API

Creating a QGIS plugin

Distributing a plugin

Creating a standalone application

Storing and reading global preferences

Storing and reading project preferences

Accessing the script path from within your script

Chapter 2. Querying Vector Data

Introduction

Loading a vector layer from a file sample

Loading a vector layer from a spatial database

Examining vector layer features

Examining vector layer attributes

Filtering a layer by geometry

Filtering a layer by attributes

Buffering a feature intermediate

Measuring the distance between two points

Measuring the distance along a line sample

Calculating the area of a polygon

Creating a spatial index

Calculating the bearing of a line

Loading data from a spreadsheet

Chapter 3. Editing Vector Data

Introduction

Creating a vector layer in memory

Adding a point feature to a vector layer

Adding a line feature to a vector layer

Adding a polygon feature to a vector layer

Adding a set of attributes to a vector layer

Adding a field to a vector layer

Joining a shapefile attribute table to a CSV file

Moving vector layer geometry

Changing a vector layer feature's attribute

Deleting a vector layer feature

Deleting a vector layer attribute

Reprojecting a vector layer

Converting a shapefile to KML

Merging shapefiles

Splitting a shapefile

Generalizing a vector layer

Dissolving vector shapes

Performing a union on vector shapes

Rasterizing a vector layer

Chapter 4. Using Raster Data

Introduction

Loading a raster layer

Getting the cell size of a raster layer

Obtaining the width and height of a raster

Counting raster bands

Swapping raster bands

Querying the value of a raster at a specified point

Reprojecting a raster

Creating an elevation hillshade

Creating vector contours from elevation data

Sampling a raster dataset using a regular grid

Adding elevation data to line vertices using a digital elevation model

Creating a common extent for rasters

Resampling raster resolution

Counting the unique values in a raster

Mosaicing rasters

Converting a TIFF image to a JPEG image

Creating pyramids for a raster

Converting a pixel location to a map coordinate

Converting a map coordinate to a pixel location

Creating a KML image overlay for a raster

Classifying a raster

Converting a raster to a vector

Georeferencing a raster from control points

Clipping a raster using a shapefile

Chapter 5. Creating Dynamic Maps

Introduction

Accessing the map canvas

Changing the map units

Iterating over layers

Symbolizing a vector layer

Rendering a single band raster using a color ramp algorithm

Creating a complex vector layer symbol

Using icons as vector layer symbols

Creating a graduated vector layer symbol renderer

Creating a categorized vector layer symbol

Creating a map bookmark

Navigating to a map bookmark

Setting scale-based visibility for a layer

Using SVG for layer symbols

Using pie charts for symbols

Using the OpenStreetMap service

Using the Bing aerial image service

Adding real-time weather data from OpenWeatherMap

Labeling features

Changing map layer transparency

Adding standard map tools to the canvas

Using a map tool to draw points on the canvas

Using a map tool to draw polygons or lines on the canvas

Building a custom selection tool

Creating a mouse coordinate tracking tool

Chapter 6. Composing Static Maps

Introduction

Creating the simplest map renderer

Using the map composer

Adding labels to a map for printing

Adding a scale bar to the map

Adding a north arrow to the map

Adding a logo to the map

Adding a legend to the map

Adding a custom shape to the map

Adding a grid to the map

Adding a table to the map

Adding a world file to a map image

Saving a map to a project

Loading a map from a project

Chapter 7. Interacting with the User

Introduction

Using log files

Creating a simple message dialog

Creating a warning dialog

Creating an error dialog

Displaying a progress bar

Creating a simple text input dialog

Creating a file input dialog

Creating a combobox

Creating radio buttons

Creating checkboxes

Creating tabs

Stepping the user through a wizard

Keeping dialogs on top

Chapter 8. QGIS Workflows

Introduction

Creating an NDVI

Geocoding addresses

Creating raster footprints

Performing network analysis

Routing along streets

Tracking a GPS

Creating a mapbook

Finding the least cost path

Performing nearest neighbor analysis

Creating a heat map

Creating a dot density map

Collecting field data

Computing road slope using elevation data

Geolocating photos on the map

Image change detection

Chapter 9. Other Tips and Tricks

Introduction

Creating tiles from a QGIS map

Adding a layer to geojson.io

Rendering map layers based on rules

Creating a layer style file

Using NULL values in PyQGIS

Using generators for layer queries

Using alpha values to show data density

Using the __geo_interface__ protocol

Generating points along a line

Using expression-based labels

Creating dynamic forms in QGIS

Calculating length for all selected lines

Using a different status bar CRS than the map

Creating HTML labels in QGIS

Using OpenStreetMap's points of interest in QGIS

Visualizing data in 3D with WebGL

Visualizing data on a globe