Mastering QGIS

Book Image

Mastering QGIS

Book Image

Mastering QGIS

Overview of this book

Mastering QGIS

Credits

Foreword

About the Authors

About the Authors

About the Reviewers

About the Reviewers

www.PacktPub.com

www.PacktPub.com

Preface

Free Chapter

A Refreshing Look at QGIS

A Refreshing Look at QGIS

QGIS download and installation

Working with coordinate reference systems

Working with tables

Adding functionality with plugins

Creating Spatial Databases

Creating Spatial Databases

Fundamental database concepts

Creating a spatial database

Importing data into a SpatiaLite database

Exporting tables out of SpatiaLite as a shapefile

Managing tables

Creating queries and views

Styling Raster and Vector Data

Styling Raster and Vector Data

Choosing and managing colors

Managing color ramps

Styling single band rasters

Styling multiband rasters

Creating a raster composite

Raster color rendering

Raster resampling

Styling vectors

Vector layer rendering

Using diagrams to display thematic data

Saving, loading, and setting default styles

Preparing Vector Data for Processing

Preparing Vector Data for Processing

Merging shapefiles

Creating spatial indices

Checking for geometry errors

Converting vector geometries

Using basic vector geoprocessing tools

Defining coordinate reference systems

Advanced field calculations

Complex spatial and aspatial queries

Preparing Raster Data for Processing

Preparing Raster Data for Processing

Reclassifying rasters

Rescaling rasters

Creating a raster mosaic

Generating raster overviews (pyramids)

Converting between raster and vector data models

Creating raster surfaces via interpolation

Advanced Data Creation and Editing

Advanced Data Creation and Editing

Creating points from coordinate data

Geocoding address-based data

Georeferencing imagery

Checking the topology of vector data

Repairing topological errors via topological editing

The Processing Toolbox

The Processing Toolbox

About the processing toolbox

Performing raster analyses with GRASS

Exploring hydrologic analyses with TauDEM

R

Automating Workflows with the Graphical Modeler

Automating Workflows with the Graphical Modeler

An introduction to the graphical modeler

Opening the graphical modeler

Configuring the modeler and naming a model

Adding algorithms

Running a model

Editing a model

Documenting a model

Saving, loading, and exporting models

Executing model algorithms iteratively

Using batch processing with models

Converting a model into a Python script

Creating QGIS Plugins with PyQGIS and Problem Solving

Creating QGIS Plugins with PyQGIS and Problem Solving

Webography - where to get API information and PyQGIS help

The Python Console

Exploring iface and QGis

Exploring a QGIS API in the Python Console

Creating a plugin structure with Plugin Builder

A simple plugin example

Setting up a debugging environment

Debugging session example

PyQGIS Scripting

PyQGIS Scripting

Where to learn Python basics

Vector structure

Iterating over features

Editing features

Running processing toolbox algorithms

Running an external algorithm or command

Interacting with the map canvas

Index

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Creating raster surfaces via interpolation

QGIS supports surface interpolation from vector points to a raster using the Interpolation plugin. The Interpolation tool supports Inverse Distance Weighted (IDW) and Triangular Interpolation (TIN). To enable the Interpolation plugin, click on Manage and Install Plugins under Plugins.

As an example of how to use the Interpolation tool, let's use the Pecos DEM Points.shp sample file to interpolate a surface using IDW:

Add Pecos DEM Points.shp to the map canvas.
Open the Interpolation plugin tool by navigating to Raster | Interpolation | Interpolation. The tool is shown in the following figure and uses the Pecos DEM Points.shp sample file as the input vector layer:
The interface of the Interpolation tool is identical whether IDW or TIN is chosen as the interpolation method. The only exceptions are the interpolation method parameters, which can be set by clicking on the configure button (). For this example, we will only cover the IDW parameter (distance...