Python Essentials in ArcGIS 1: An Introduction

71 Pages·2012·1.28 MB·English

by  Drew Flater

Lecture 12
Programming for automation of
common data management tasks
Daniel P. Ames
Hydroinformatics
Fall 2012
This work was funded by National
Science Foundation Grant EPS
1135482
Goals this Week…
• To learn the basics of Python Scripting for
automation of basic geoprocessing and
database management tasks.
• Tuesday focus on intro to Python and ArcPy
for mapping and geoprocessing tasks
• Thursday focus on PyODBC and using Python
to automate database tasks
Useful Software to have on your
laptop computer in class…
• ArcGIS. http://www.esri.com/software/arcgis/arcgis-
for-desktop/free-trial
• Python. www.Python.org.
• PyODBC. http://code.google.com/p/pyodbc/.
• ArcMap 10.x comes with Python 2.6. It installs it in
your C: folder under C:\Python\ArcGIS10\.
• PyODBC. http://code.google.com/p/pyodbc/downlo
ads/detail?name=pyodbc-3.0.6.win32-
py2.6.exe&can=2&q=
Slide Credits
• 2010 Mitch Marcus and Varun Aggarwala,
University of Pennsylvania
• 2010 ESRI Conference Workshop: Python
Essentials in ArcGIS-I
• 2002 LinuxWorld Tutorial: Introduction to
Python by Guido van Rossum
Python
 Python is an open source scripting language.
 Developed by Guido van Rossum in the early 1990s
 Named after Monty Python
 Available on eniac
 Available for download from http://www.python.org
CIS 530 - Intro to NLP 5

Why Python?
 Powerful but unobtrusive object system
 Every value is an object
 Classes guide but do not dominate object
construction
 Powerful collection and iteration
abstractions
 Dynamic typing makes generics easy
Python
 Interpreted language: works with an
evaluator for language expressions
 Dynamically typed: variables do not have a
predefined type
 Rich, built-in collection types:
 Lists
 Tuples
 Dictionaries (maps)
 Sets
 Concise
Language features
 Indentation instead of braces
 Newline separates statements
 Several sequence types
 Strings ’…’: made of characters, immutable
 Lists […]: made of anything, mutable
 Tuples (…) : made of anything, immutable
 Powerful subscripting (slicing)
 Functions are independent entities (not all
functions are methods)
 Exceptions
Basics