So now that Python has been proven as a great tool, who do you begin.  Sure you can start with www.python.org but the is so much information is on the site you are not sure where to start.  Well, there is a endless source for finding code samples.  Search the ArcGIS Help Library to find the tool you would like to use.  Then scroll to near the bottom and there is a code sample to use in the Python Window or as a stand-alone script for that particular tool.

Another  method that saves a lot of time is to use ModelBuilder and create a model for the desired process.  Once you get the model working then export the model as a script (Model > Export > Script).  The output of this export provides a great starting point for expanding on the python code to get the task accomplished.

Here is a quick example from the Buffer tool help document:

Python Widnow Script
import arcpy
arcpy.env.workspace = "C:/data"
arcpy.Buffer_analysis("roads", "C:/output/majorrdsBuffered" "100 Feet", "FULL", "ROUND", "LIST", "Distance")

Stand-alone Script
# Name: Buffer.py
# Description: Find areas of suitable vegetation which exclude areas heavily impacted by major roads
# Author: ESRI

# import system modules
import arcpy
from arcpy import env

# Set environment settings
env.workspace = “C:/data/Habitat_Analysis.gdb”

# Select suitable vegetation patches from all vegetation
veg = “vegtype”
suitableVeg = “C:/output/Output.gdb/suitable_vegetation”
whereClause = “HABITAT = 1″
arcpy.Select_analysis(veg, suitableVeg, whereClause)

# Buffer areas of impact around major roads
roads = “majorrds”
roadsBuffer = “C:/output/Output.gdb/buffer_output”
distanceField = “Distance”
sideType = “FULL”
endType = “ROUND”
dissolveType = “LIST”
dissolveField = “Distance”
arcpy.Buffer_analysis(roads, roadsBuffer, distanceField, sideType, endType, dissolveType, dissolveField)

# Erase areas of impact around major roads from the suitable vegetation patches
eraseOutput = “C:/output/Output.gdb/suitable_vegetation_minus_roads”
xyTol = “1 Meters”
arcpy.Erase_analysis(suitableVeg, roadsBuffer, eraseOutput, xyTol)

So now that you have that block of code or *.dll file, what do you do with it?  Well, here are two quick videos to show how to implement VBA code.

Add VBA Code to Toolbar Button

Add DLL File

Note: Videos are broadcast through youtube.com.  Some browsers may block this content.

Related Blogs

Intro to Programming with ArcObjects

ArcObjects Tutorial I-Create Custom Command

Start Programming in GIS

Related Books

GIS in and of itself is a very technical system.  Just think about the visual part of a map and then add in the data that lies behind the visualization.  Then on top of everything, add the ability to do extensive analysis with the data.  Each of these parts are held together with a Graphic User Interface such as ArcGIS, MapInfo, or GoogleEarth.  While already being overwhelmed by the data alone, think about the programming that goes into these GUI’s.  You may tell yourself that programming is an area that you plan to stay far away from; however. I believe that there are extremely great benefits to knowing a little bit about programming.

In order to get your feet wet in GIS programming, I would suggest learning a little bit about Visual Basic for Applications. VBA is an event driven form of Visual Basic.  It usually relies on applications to serve as its host as it does not work independently.  Microsoft Software is the main housing unit for VBA, but it does come with other software packages such as AutoCAD, WordPerfect, and ArcGIS. VBA allows the user to perform repetitive and/or extensive tasks in a simple to use format.  These formats can include but are not limited to a Button, Tool, Form, and Macro.

To Begin, find where the Visual Basic for Applications program is located. In ArcMap or ArcCatalog click Tools -> Marcos -> Visual Basic Editor… (This is basic for all applications with VBA). The shortcut is Atl+F11. This will open Microsoft Visual Basic in a new window.

Start by exploring the various areas presented. Familiarize yourself with the Menu bar. Many of the options will be completely foreign, but you will learn how to apply them to programming eventually.

Next, you should see a Project Explorer Window (If you do not see this window, click View -> Project Explorer). The Project Explorer displays each project that is open. Normal is the master application template. Any changes to this project will apply to all documents. You may also see Project (Document_Name). Changes within this project will only apply to that project. Keeping this in mind will enable you to customize at the individual document level and also at the application template level. There are objects under each project. You can toggle between the object and the code with the buttons at the top of this window.

The next area to look at is the Properties Window (If you do not see this window, click View -> Properties Window). This is where you can name the various objects within the project as well as assign properties. These will vary by object.

The last area to bring attention to is the Coding Window (the large white space). This area is where code is placed to carry out your desired procedure. Each object will have its own separate coding area.

Now that you have a general overview of Microsoft VBA, I would recommend continuing to explore other areas that I may not have covered. If you are not sure what something is, use the help document (Help -> Microsoft Visual Basic Help or hit F1). There is a wealth of information located here.

Note:  VBA is not the only programming language in GIS; however, it is an excellent language to begin learning GIS programming.

Related Topics on GIS Pathway

Related Books

• Getting to Know ArcObjects (GIS Pathway Review)
• VBA for Dummies
• VB and VBA in a Nutshell: The Languages
• Absolute Beginner’s Guide to VBA (Absolute Beginner’s Guide)
• Office VBA Macros You Can Use Today: Over 100 Amazing Ways to Automate Word, Excel, PowerPoint, Outlook, and Access
• VBA Developer’s Handbook, 2nd Edition

Related Websites

• Microsoft Developer Network: VBA
• ESRI Training (Search Topic: VBA)

1. ArcScripts

This the best place to find code.  Since it is maintained by ESRI, there is no larger collected anywhere online.  The GIS community uplaods various scripts and the site puts them in an easy to search format.  Many programming languages are available.

Here are a few of my favorite:

Spell Check

Add Text Elements to Layout

2. ESRI Support Center User Forums

The ESRI Support Center User Forums has some great coding resources.  Users post their coding problems and other users respond to their problems.  Usually, the final output is a completed block of code that anyone can use.  This link takes you to the most recent posts for VBA.  You can also search the forums for the code that you need.  Including VBA will provide you with better returns.

3. Customizing ArcGIS Desktop with VBA

The ESRI Resource Center is great site to find a good bit of information for programming with VBA.  Although it corresponds with the ArcGIS 9.3 release, there are some excellent benefits that apply to earlier versions.

4. Utah GIS Portal

The Utah GIS Partal is a hidden wealth of information.  Although it does not provide the smae number of scripts the the ESRI website does, it does have some good samples.  In addition to VBA, it also provides code for Python and C#.  Search the other areas of this site to find more GIS resources.

If you know of any good sites, please let me know so that I can update this list.

I recently pick up this book, Getting to Know ArcObjects.  It was really helpful.  It has helped me to understand VBA a lot more.  It covers various applications including customizing ArcDesktop, Creating Forms, Automating Page Layouts, Creating UIControlButtons, Automating Labels and Symbology and so much more.  The chapters are layed out with instructive text and then a hands on tutorial.

Once I got this book, I worked through it in 5 days.  If you have been wanting to learn more about programming in GIS then this is the book for you.  Check it out today!

Getting to Know ArcObjects (With CD-ROM)

Find other book reviews here!