Book Image

Programming ArcGIS with Python Cookbook, Second Edition

By : Eric Pimpler
Book Image

Programming ArcGIS with Python Cookbook, Second Edition

By: Eric Pimpler

Overview of this book

The book kicks off with the fundamentals of starting to use Python with ArcGIS, followed by recipes on managing map documents and layers, including how to find and fix broken data links in these files. In the second part of the book, you will learn to create custom geoprocessing tools and how to use the Attribute and Location tools to select specific features. The third part of the book covers topics for advanced users including the REST API, and also teaches you how to use Python with ArcGIS Pro. The book finishes with appendices covering how to automate Python scripts, and the five things that should be at the back of every GIS programmer's mind.

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Programming ArcGIS with Python Cookbook, Second Edition
Eric Pimpler
Jul, 2015 | 366 pages
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Table of Contents (17 chapters)
Preface
Preface
What this book covers
What you need for this book
Who this book is for
Sections
Conventions
Reader feedback
Customer support
Free Chapter
1
1. Fundamentals of the Python Language for ArcGIS
1. Fundamentals of the Python Language for ArcGIS
Using IDLE for Python script development
Using the ArcGIS Python window
Python language fundamentals
Summary
2
2. Managing Map Documents and Layers
2. Managing Map Documents and Layers
Introduction
Referencing the current map document
Referencing map documents on a disk
Getting a list of layers in a map document
Restricting the list of layers
Zooming in to selected features
Changing the map extent
Adding layers to a map document
Inserting layers into a map document
Updating layer symbology
Updating layer properties
Working with time-enabled layers in a data frame
3
3. Finding and Fixing Broken Data Links
3. Finding and Fixing Broken Data Links
Introduction
Finding broken data sources in your map document and layer files
Fixing broken data sources with MapDocument.findAndReplaceWorkspacePaths()
Fixing broken data sources with MapDocument.replaceWorkspaces()
Fixing individual layer and table objects with replaceDataSource()
Finding broken data sources in all map documents in a folder
4
4. Automating Map Production and Printing
4. Automating Map Production and Printing
Introduction
Creating a list of layout elements
Assigning a unique name to layout elements
Restricting the layout elements returned by ListLayoutElements()
Updating the properties of layout elements
Getting a list of available printers
Printing maps with PrintMap()
Exporting a map to a PDF file
Exporting a map to an image file
Exporting a report
Building a map book with Data Driven Pages and ArcPy mapping
Publishing a map document to an ArcGIS Server service
5
5. Executing Geoprocessing Tools from Scripts
5. Executing Geoprocessing Tools from Scripts
Introduction
Finding geoprocessing tools
Retrieving a toolbox alias
Executing geoprocessing tools from a script
Using the output of a tool as an input to another tool
6
6. Creating Custom Geoprocessing Tools
6. Creating Custom Geoprocessing Tools
Introduction
Creating a custom geoprocessing tool
Creating a Python toolbox
7
7. Querying and Selecting Data
7. Querying and Selecting Data
Introduction
Constructing a proper attribute query syntax
Creating feature layers and table views
Selecting features and rows with the Select Layer by Attribute tool
Selecting features with the Select by Location tool
Combining a spatial and attribute query with the Select by Location tool
8
8. Using the ArcPy Data Access Module with Feature Classes and Tables
8. Using the ArcPy Data Access Module with Feature Classes and Tables
Introduction
Retrieving features from a feature class with SearchCursor
Filtering records with a where clause
Improving cursor performance with geometry tokens
Inserting rows with InsertCursor
Updating rows with UpdateCursor
Deleting rows with UpdateCursor
Inserting and updating rows inside an edit session
Reading geometry from a feature class
Using Walk() to navigate directories
9
9. Listing and Describing GIS Data
9. Listing and Describing GIS Data
Introduction
Working with the ArcPy list functions
Getting a list of fields in a feature class or table
Using the Describe() function to return descriptive information about a feature class
Using the Describe() function to return descriptive information about a raster image
10
10. Customizing the ArcGIS Interface with Add-ins
10. Customizing the ArcGIS Interface with Add-ins
Introduction
Downloading and installing the Python Add-in Wizard
Creating a button add-in and using the Python add-ins module
Installing and testing an add-in
Creating a tool add-in
11
11. Error Handling and Troubleshooting
11. Error Handling and Troubleshooting
Introduction
Exploring the default Python error message
Adding Python exception handling structures (try/except/else)
Retrieving tool messages with GetMessages()
Filtering tool messages by the level of severity
Testing for and responding to specific error messages
12
12. Using Python for Advanced ArcGIS
12. Using Python for Advanced ArcGIS
Introduction
Getting started with the ArcGIS REST API
Making HTTP requests and parsing the response with Python
Getting layer information with the ArcGIS REST API and Python
Exporting a map with the ArcGIS REST API and Python
Querying a map service with the ArcGIS REST API and Python
Geocoding with the Esri World Geocoding Service
Using FieldMap and FieldMappings
Using a ValueTable to provide multivalue input to a tool
13
13. Using Python with ArcGIS Pro
13. Using Python with ArcGIS Pro
Introduction
Using the new Python window in ArcGIS Pro
Coding differences between ArcGIS for Desktop and ArcGIS Pro
Installing Python for ArcGIS Pro
Converting ArcGIS for Desktop Python code to ArcGIS Pro
14
A. Automating Python Scripts
A. Automating Python Scripts
Introduction
Running Python scripts from the command line
Using sys.argv[ ] to capture command-line input
Adding Python scripts to batch files
Scheduling batch files to run at prescribed times
15
B. Five Python Recipes Every GIS Programmer Should Know
B. Five Python Recipes Every GIS Programmer Should Know
Introduction
Reading data from a delimited text file
Sending e-mails
Retrieving files from an FTP server
Creating ZIP files
Reading XML files
16
Index
Index

Using the Describe() function to return descriptive information about a raster image

Raster files also contain descriptive information that can be returned by the Describe() function.

Getting ready

A raster dataset can also be described through the use of the Describe() function. In this recipe, you will describe a raster dataset by returning its extent and spatial reference. The Describe() function contains a reference to the general purpose Dataset properties group and also contains a reference to the SpatialReference object for the dataset. The SpatialReference object can then be used to get detailed spatial reference information for the dataset.

How to do it…

Follow these steps to learn how to obtain descriptive information about a raster image file.

  1. Open IDLE and create a new script window.

  2. Save the script as C:\ArcpyBook\Ch9\DescribeRaster.py.

  3. Import the arcpy module:

    import arcpy

  4. Set the workspace:

    arcpy.env.workspace = "C:/ArcpyBook/data "

  5. Start a try block:

    try:

  6. Call the Describe() function...

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