Book Image

Learning Geospatial Analysis with Python

By : Joel Lawhead
4 (1)
Book Image

Learning Geospatial Analysis with Python

4 (1)
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. It is an approach to use statistical analysis and other informational engineering to data which has a geographical or geospatial aspect. And this typically involves applications capable of geospatial display and processing to get a compiled and useful data. "Learning Geospatial Analysis with Python" uses the expressive and powerful Python programming language to guide you through geographic information systems, remote sensing, topography, and more. It explains how to use a framework in order to approach Geospatial analysis effectively, but on your own terms. "Learning Geospatial Analysis with Python" starts with a background of the field, a survey of the techniques and technology used, and then splits the field into its component speciality areas: GIS, remote sensing, elevation data, advanced modelling, and real-time data. This book will teach you everything there is to know, from using a particular software package or API to using generic algorithms that can be applied to Geospatial analysis. 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. "Learning Geospatial Analysis with Python" will round out your technical library with handy recipes and a good understanding of a field that supplements many a modern day human endeavors.
Table of Contents (17 chapters)
Learning Geospatial Analysis with Python
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

OGR


We touched on OGR as a way to handle WKT strings but its real power is as a universal vector library. This book strives for pure Python solutions but no single library even comes close to the variety of formats OGR can process.

Let's read a sample point shapefile using the OGR Python API. The sample shapefile can be downloaded as a zip file here: https://geospatialpython.googlecode.com/files/point.zip

This point shapefile has five points with single digit, positive coordinates. The attributes list the order in which the points were created, making it useful for testing. This simple example will read in the point shapefile, loop through each feature, and then print the x and y value of each point plus the value of the first attribute field:

>>> from osgeo import ogr
>>> shp = ogr.Open("point.shp")
>>> layer = shp.GetLayer()
>>> feature = layer.GetNextFeature()
>>> for feature in layer:
...     geometry = feature.GetGeometryRef()
...     print...