#### Overview of this book

QGIS is a user-friendly, cross-platform desktop geographic information system used to make maps and analyze spatial data. QGIS allows users to understand, question, interpret, and visualize spatial data in many ways that reveal relationships, patterns, and trends in the form of maps. This book is a collection of simple to advanced techniques that are needed in everyday geospatial work, and shows how to accomplish them with QGIS. You will begin by understanding the different types of data management techniques, as well as how data exploration works. You will then learn how to perform classic vector and raster analysis with QGIS, apart from creating time-based visualizations. Finally, you will learn how to create interactive and visually appealing maps with custom cartography. By the end of this book, you will have all the necessary knowledge to handle spatial data management, exploration, and visualization tasks in QGIS.
QGIS 2 Cookbook
Credits
www.PacktPub.com
Preface
Free Chapter
Data Input and Output
Data Management
Common Data Preprocessing Steps
Classic Vector Analysis
Raster Analysis I
Raster Analysis II
QGIS and the Web
Extending QGIS
Up and Coming
Index

## Exploring numeric value distribution in a column

In this recipe, we will look at how to explore the properties of a column of numeric values. We will look at the tools that QGIS offers and apply them to analyze the elevation values in our sample POI dataset.

To follow this recipe, please load `poi_names_wake.shp`. If you followed the previous recipe, Listing unique values in a column, you can continue directly from there.

### How to do it…

A good way to get a first impression of the properties of a numeric column is using the Basic Statistics tool from Vector. This allows you to calculate statistical values, such as the minimum and maximum values, mean and median, standard deviation, and sum.

If you want to examine the distribution of elevation values, there is the handy Statist plugin. Statist generates an interactive histogram representation of the value distribution:

1. Install Statist using Plugin Manager.

2. Start Statist from the Vector menu.

3. Specify Input vector layer and the attribute...