Book Image

Geospatial Analysis with SQL

By : Bonny P McClain
Book Image

Geospatial Analysis with SQL

By: Bonny P McClain

Overview of this book

Geospatial analysis is industry agnostic and a powerful tool for answering location questions. Combined with the power of SQL, developers and analysts worldwide rely on database integration to solve real-world spatial problems. This book introduces skills to help you detect and quantify patterns in datasets through data exploration, visualization, data engineering, and the application of analysis and spatial techniques. You will begin by exploring the fundamentals of geospatial analysis where you’ll learn about the importance of geospatial analysis and how location information enhances data exploration. Walter Tobler’s second law of geography states, “the phenomenon external to a geographic area of interest affects what goes on inside.” This quote will be the framework of the geospatial questions we will explore. You’ll then observe the framework of geospatial analysis using SQL while learning to create spatial databases and SQL queries and functions. By the end of this book, you will have an expanded toolbox of analytic skills such as PostGIS and QGIS to explore data questions and analysis of spatial information.
Table of Contents (13 chapters)
Free Chapter
1
Section 1: Getting Started with Geospatial Analytics
6
Section 2: SQL for Spatial Analytics

Developing knowledge about geographic space

The PostGIS documentation is an important tool for improving your understanding of spatial algorithms and how to execute efficient SQL queries. As we move past inquiry and into efficiency, it is important to pay attention to additional details. These will be explained as we move through the chapter.

Let’s begin by understanding spatial indexing. Unique to spatial databases, indexing is necessary to expedite searches and improve the speed of our queries.

But wait – you might be thinking – how do you index geometries? Isn’t that what makes a spatial database different? The simple answer is a spatial index is looking at bounding boxes—not simply the lines generated from their edges. Bounding boxes are rectangular polygons containing an object or an area of interest. Identified by xmax, xmin, ymax, and ymin, a bounding box is slightly different from an extent, as it can contain an extent but does not have...