Book Image

PostGIS Cookbook

Book Image

PostGIS Cookbook

Overview of this book

Table of Contents (18 chapters)
PostGIS Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Introduction


In this chapter, the recipes are presented in a step-by-step workflow that you may apply while working with a raster. This entails loading the raster, getting a basic understanding of the raster, processing and analyzing it, and delivering it to consumers. We intentionally add some detours to the workflow to reflect the reality that the raster, in its original form, may be confusing and not suitable for analysis. At the end of this chapter, you should be able to take the lessons learned from the recipes and confidently apply them to solve your raster problems.

Before going further, we should describe what a raster is and what a raster is used for. At the simplest level, a raster is a photo or image with information describing where to place the raster on the Earth's surface. A photograph typically has three sets of values, one set for each primary color (red, green, and blue). A raster also has sets of values, often more than those found in a photograph. Each set of values is...