Book Image

Learning Geospatial Analysis with Python

By : Joel Lawhead
Book Image

Learning Geospatial Analysis with Python

By: Joel Lawhead

Overview of this book

Geospatial Analysis is used in almost every field you can think of from medicine, to defense, to farming. This book will guide you gently into this exciting and complex field. It walks you through the building blocks of geospatial analysis and how to apply them to influence decision making using the latest Python software. Learning Geospatial Analysis with Python, 2nd Edition uses the expressive and powerful Python 3 programming language to guide you through geographic information systems, remote sensing, topography, and more, while providing a framework for you to approach geospatial analysis effectively, but on your own terms. We start by giving you a little background on the field, and a survey of the techniques and technology used. We then split the field into its component specialty areas: GIS, remote sensing, elevation data, advanced modeling, and real-time data. This book will teach you everything you need to know about, Geospatial Analysis from using a particular software package or API to using generic algorithms that can be applied. This book focuses on pure Python whenever possible to minimize compiling platform-dependent binaries, so that you don’t become bogged down in just getting ready to do analysis. This book will round out your technical library through handy recipes that will give you a good understanding of a field that supplements many a modern day human endeavors.
Table of Contents (17 chapters)
Learning Geospatial Analysis with Python Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Reprojection


While reprojection is less common these days because of more advanced methods of data distribution, sometimes you do need to reproject a shapefile. The pure Python utm module works for reference system conversion, but for a full reprojection we need some help from the OGR Python API. The OGR API contained in the osgeo module has the Open Spatial Reference module, also known as osr, which we'll use for reprojection.

As an example, we'll use a point shapefile containing New York City museum and gallery locations in the Lambert conformal projection. We'll reproject it to WGS84 geographic (or unproject it rather). You can download this zipped shapefile at http://git.io/vLbT4

The following minimalist script reprojects the shapefile. The geometry is transformed and written to the new file, but the dbf file is simply copied to the new name as we aren't changing it. The standard Python shutil module, which is the shortened form for shell utilities, is used to copy dbf. The source and...