Book Image

Geospatial Development By Example with Python

By : Pablo Carreira
5 (1)
Book Image

Geospatial Development By Example with Python

5 (1)
By: Pablo Carreira

Overview of this book

From Python programming good practices to the advanced use of analysis packages, this book teaches you how to write applications that will perform complex geoprocessing tasks that can be replicated and reused. Much more than simple scripts, you will write functions to import data, create Python classes that represent your features, and learn how to combine and filter them. With pluggable mechanisms, you will learn how to visualize data and the results of analysis in beautiful maps that can be batch-generated and embedded into documents or web pages. Finally, you will learn how to consume and process an enormous amount of data very efficiently by using advanced tools and modern computers’ parallel processing capabilities.
Table of Contents (17 chapters)
Geospatial Development By Example with Python
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Storing information on a database


In the previous chapters, the basic workflow was to import all the data into memory as Python objects every time we ran the code. That's perfectly fine and efficient when we work with small pieces of data.

At some point, you may have noticed that the performance of our code was debilitated, especially when we started importing country boundaries along with all the attributes. This happened because importing attributes is slow.

Secondly, although our filtering mechanisms worked pretty well, we may have problems when dealing with huge datasets.

The formula to solve these problems is very simple and consists of only two basic ingredients:

  • Get only what you need

  • Use indexed searches

The first point is about getting only the records you need, as well as getting only the attributes that are desired for a given analysis.

The second point is about how things are found. In our method, a loop tests every record for a condition until the desired one is found (that is, the...