1. Introduction Presenter: James Zollweg, Ph.D.
Associate Professor of Water Resources and GIS
The College at Brockport
NYS GIS Association – Python Training, Session 2 – July 17, 2012

2. Why a Python Seminar?
1. Python is an increasingly important part of ArcGIS mapping and geoprocessing
2. Python 'scripting' is a powerful tool for modeling and process automation
3. Build a greater sense of community among GIS professionals in NYS via shared professional development
NYS GIS Association – Python Training, Session 2 – July 17, 2012

3. Need to know
1. The elements of Python – a general purpose programming language
2. ArcPy - provides Python access for all geoprocessing tools, as well as a wide variety of useful functions and classes for working with and interrogating GIS data.
3. Proficiency in ArcGIS mapping and geoprocessing
NYS GIS Association – Python Training, Session 2 – July 17, 2012

4. Brief Review of Python Essentials
Python is a free, cross-platform, open-source programming language that is both powerful and easy to learn. It is widely used and supported.
To learn more about Python, visit python.org.
NYS GIS Association – Python Training, Session 2 – July 17, 2012

5. Values and variables
NYS GIS Association – Python Training, Session 2 – July 17, 2012

6. Definite repetition
NYS GIS Association – Python Training, Session 2 – July 17, 2012

7. Indefinite Repetition
NYS GIS Association – Python Training, Session 2 – July 17, 2012

8. Lists
NYS GIS Association – Python Training, Session 2 – July 17, 2012

9. List Layers
NYS GIS Association – Python Training, Session 2 – July 17, 2012

10. List Attributes
NYS GIS Association – Python Training, Session 2 – July 17, 2012

11. So, how do you REALLY get started?
Study example scripts
Example: ReplaceWithLayerFile.py
NYS GIS Association – Python Training, Session 2 – July 17, 2012

12. Title
NYS GIS Association – Python Training, Session 2 – July 17, 2012

13. Exception Handling
NYS GIS Association – Python Training, Session 2 – July 17, 2012

14. Exception Handling
NYS GIS Association – Python Training, Session 2 – July 17, 2012

15. Title
NYS GIS Association – Python Training, Session 2 – July 17, 2012

16. A VERY useful alternative
Rather than scouring scripts for ideas (a good way to learn “in general”), let’s make ArcGIS write code snippets for us!
NYS GIS Association – Python Training, Session 2 – July 17, 2012

17. A familiar geoprocessing operation...
NYS GIS Association – Python Training, Session 2 – July 17, 2012

18. Access the “results” of GP operation
NYS GIS Association – Python Training, Session 2 – July 17, 2012

19. Copy operation to a Python “snippet”
NYS GIS Association – Python Training, Session 2 – July 17, 2012

20. The snippet
# Replace a layer/table view name with a path to a dataset (which can be a layer file) or create the layer/table view within the script# The following inputs are layers or table views: "recreation"arcpy.Buffer_analysis("recreation","C:/tem p/tests/buff3.shp","100 Meters","FULL","ROUND","NONE","#")
NYS GIS Association – Python Training, Session 2 – July 17, 2012

21. The snippet (with <cr>)
# Replace a layer/table view name with a path to a dataset (which can be a layer file) or create the layer/table view within the script
# The following inputs are layers or table views: "recreation“
arcpy.Buffer_analysis("recreation","C:/temp/tests/buff3.s hp","100 Meters","FULL","ROUND","NONE","#")
NYS GIS Association – Python Training, Session 2 – July 17, 2012

22. Model Builder -> Python
(I’ll show how to use Model Builder later in the presentation)
NYS GIS Association – Python Training, Session 2 – July 17, 2012

23. Export to Python script
NYS GIS Association – Python Training, Session 2 – July 17, 2012

24. The result
NYS GIS Association – Python Training, Session 2 – July 17, 2012

25. Excellent source of information
NYS GIS Association – Python Training, Session 2 – July 17, 2012

26. Another example
NYS GIS Association – Python Training, Session 2 – July 17, 2012

27. Output
NYS GIS Association – Python Training, Session 2 – July 17, 2012

28. Beware – repetition does not functionally export fro MB
NYS GIS Association – Python Training, Session 2 – July 17, 2012

29. Non-functional Python code generated
needs to be replaced with proper Python “for” loop
NYS GIS Association – Python Training, Session 2 – July 17, 2012

30. Replace with proper Python repetition
NYS GIS Association – Python Training, Session 2 – July 17, 2012

31. Shameless plug for the NYS GIS Association
NYS GIS Association – Python Training, Session 2 – July 17, 2012

32. The NYS GIS Association “App site”
Members-only site for sharing scripts and snippets
“Moderated” and organized
Watch for details!
NYS GIS Association – Python Training, Session 2 – July 17, 2012

33. Thanks!
Congratulations for jousting with a useful, important and difficult topic!
NYS GIS Association – Python Training, Session 2 – July 17, 2012