2. Presentation topics
In this presentation I will talk about:
– How automation can be used to execute some geodatabase
tasks;
– Python, ArcPy and its interaction with the geodatabase;
– Use cases.
3. What can we use automation for with
geodatabases?
In a general way, we use automation with geodatabases to:
– Explore geodatabase content;
– Simplify the execution of frequent administration tasks:
• Create indexes;
• Set privileges.
– Implement data workflows:
• conversion;
• distribution;
4. How can automation be done?
Automation of these tasks can be done using the Python
programming language.
Why Python?
– Simple and easy to learn;
– Widely adopted and well documented;
– Powerfull, with many available built-in and external modules;
– Fast to implement.
5. How can python be used with Arcgis and the
geodatabase?
The use of Python with Arcgis and the geodatabase is
simplified by the fact that:
– Python is available by default with all ArcGis 9.X and 10.X
Desktop installations;
– ‘Coding’ can be done using ArcGis Desktop ‘Python Window’ or
one of the many development environments available:
• Wingware
• pyDev
• or even Notepad++
6. How can python be used with Arcgis and the
geodatabase?
– All the interaction with the geodatabase, feature classes, rasters
or even the mxds is done through a single python package,
named ArcPy – and not with a vast library, making it easy to
access the right function or geoprocessing tool.
– If needed, in addition, specific modules provide a direct interaction
with the databases themselves:
• cx_oracle for Oracle;
• pymssql for SQL Server.
7. What is ArcPy?
This means that most of the time while scripting we will be
using ArcPy, which is:
– ESRIs python package for ArcGis 10 products - a set of modules,
classes and functions;
– ‘Upgraded’ from Arcgis version 9.X ‘arcgisscripting’.
ArcPy is divided in a small number of modules, with
names familiar to all ArcGis users:
– Mapping (to interact with mxds);
– Geostatistical analyst;
– Spatial analyst.
8. What is arcpy main purpose then?
ArcPy main purpose then is to:
– provide easy programming access to all common data structures,
geoprocessing tools and map documents (.mxd);
– Simplify the execution of repetitive manual tasks by using scripts
that are relatively fast to implement and that can be runned over
and over.
9. Whats needed to use automation with the
geodatabase?
This means that to use automation with the geodatabase
we need:
– Good understanding of geodatabases;
– Learn general python concepts and the language itself;
– Become familiar with the ArcPy package.
An easy way to start is to use both:
– Geoprocessing tools help;
– ArcPy page.
10. Use cases :
To demonstrate how ArcPy interacts with the
geodatabase, we’ll look into some examples where we
use:
– functions to explore the geodatabase;
– geoprocessing tools to automate administrative tasks;
– Both functions and geoprocessing tools to implement a ‘data
distribution’ workflow.
11. Use case #1 - explore the geodatabase :
In the first case we will see that ArcPy can be used to
explore geodatabase objects and the data itself.
It has its own functions to List:
– Datasets;
– Feature class or tables;
– Fields;
– or Rasters.
12. Use case #1 - explore the geodatabase :
It also has some specific functions to:
– ‘Describe’ the data, as the ones used to:
• Get a feature class spatial reference;
• or to Check if its versioned;
– Read and Write data, allowing us to:
• Get attribute values;
• Update or insert features.
13. Use case #2 – administrative tasks:
In this second example we will see how Arcpy can be
used to run administrative tasks on datasets or feature
classes.
This can be done by using standard geoprocessing
tools, as we know them in ArcToolbox:
– Create or remove indexes;
– Set privileges;
14. Use case #3 – automate workflow
In this third example we will see how ArcPy can be used
to make some operational workflows easyer to manage.
As an example problem:
– suppose we need to provide our operational teams with the most
updated GIS data each time they go out to the field;
– Consider that after their job is done, while still in the field, they will
update the spatial data related to the job they executed;
– In the end we want this new data in our main geodatabase.
15. Use case #3 – automate workflow
One possible workflow could be to:
1. Make a python script to create a geodatabase on the team
portable device and a ‘check-out’ replica between the main
(parent) and the team (child) geodatabase, providing them with
the data;
Replicate
Main data
Team
geodatabase geodatabase
(Parent) (Child)
16. Use case #3 – automate workflow
2. Create another python script to ‘Synchronize changes’ between
the geodatabases, updating the data, after the job is completed;
Synchronize
Main data
Team
geodatabase geodatabase
(Parent) (Child)
17. Use case #3 – automate workflow
3. To make the process simple to our users, we can also create a
custom toolbox with tools to run the scripts that check out and
then check in the data.
18. Additional resources
Python concepts and language
– Google python class
http://code.google.com/edu/languages/google-python-class/
– Dive into python
www.diveintopython.net/
Arcpy
– Visit ArcGis help library, and under Professional Library ->
Geoprocessing > The Arcpy site package
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#
/Welcome_to_the_ArcGIS_Help_Library/00r90000001n00000
0/
