You're reading from QGIS Python Programming Cookbook, Second Edition Automating geospatial development

Product type Paperback

Published in Mar 2017

Publisher Packt

ISBN-13 9781787124837

Length 464 pages

Edition 2nd Edition

Languages

Python

Tools

Eclipse

Concepts

Geospatial Analysis

Author (1):

Joel Lawhead

View More author details

Table of Contents (10) Chapters

Preface

1. Automating QGIS FREE CHAPTER

2. Querying Vector Data

3. Editing Vector Data

4. Using Raster Data

5. Creating Dynamic Maps

6. Composing Static Maps

7. Interacting with the User

8. QGIS Workflows

9. Other Tips and Tricks

Creating a file input dialog

The best way to get a filename from the user is to have them browse to the file using a dialog. You can have the user type in a filename using the text input dialog, but this method is prone to errors. In this recipe, we'll create a file dialog and print the chosen filename to the console.

Getting ready

Open the QGIS Python console by selecting the Plugins menu and then clicking on Python Console.

How to do it...

In this recipe, we will create and configure the dialog, browse to a file, and print the chosen filename, as follows:

First, we import the GUI library:
```
        from PyQt4.QtGui import * 
```

Next, we initialize the file dialog and specify its window title:

        qfd = QFileDialog() 
        title = 'Open File'

Now, we specify a path to the directory we want the file dialog to start in:
```
        path = "/Users/joellawhead/qgis_data" 
```
Then, we configure the file dialog with the preceding parameters and assign the output to a variable:
```
 ...
```

The rest of the chapter is locked

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Authors (1)

Joel Lawhead

Joel Lawhead is a PMI-certified Project Management Professional (PMP), a certified GIS Professional (GISP), and vice president of NVision Solutions, Inc., an award-winning firm specializing in geospatial technology integration and sensor engineering for NASA, FEMA, NOAA, the US Navy, and many other commercial and non-profit organizations. Joel began using Python in 1997 and started combining it with geospatial software development in 2000. He has authored multiple editions of Learning Geospatial Analysis with Python and QGIS Python Programming Cookbook, both from Packt. He is also the developer of the open source Python Shapefile Library (PyShp) and maintains a geospatial technical blog.

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