If you are familiar with building geoprocessing tools on ArcGIS Desktop, then you are a few steps away from creating and publishing your own tools to ArcGIS Server. Below is a summary of key concepts and rules—details can be found in Key concepts for geoprocessing services as well as other topics in this book.

1. Model and script tools that execute on ArcGIS Desktop will need to be modified to execute on ArcGIS Server.
• Only certain input and output parameter data types are allowed. For example, tools that have feature class input will have to be modified to have feature set input instead. It is easy and straightforward to change a model or script to take feature set input rather than feature class input.
• Due to the fact that your tools can be executed on multiple-server computers, there are specific rules about where intermediate and output data can be written. You will have to modify your models and scripts to follow these rules for writing intermediate and output data.

2. You need to think about how the outputs of your tools will be displayed in the client application. When using tools in ArcGIS Desktop, you may not give output display much thought—you use ArcMap layers to create a good cartographic display of tool outputs. ArcGIS Server clients do not have the capabilities of ArcMap, so you need to think carefully about how your outputs should be displayed and specify good symbology.
3. Geoprocessing services need to be fast and efficient. Clients want and expect fast service. Since ArcGIS Server can be serving multiple clients at once, inefficient services can overload your server. The more efficient your services, the more clients can be served with the same computing resources. You may need to tune your models and scripts for faster execution.

Guide to topics

Topic	Description
An overview of sharing tools and toolboxes	This is the overview topic for the geoprocessing documentation module Sharing tools and toolboxes. Although the topics in this module are not specific to ArcGIS Server, they do describe and discuss issues common to sharing tools, and since ArcGIS Server is just another way to share geoprocessing tools, the topics are relevant.
Key concepts for geoprocessing services	This topic describes the key concepts you need to know for building and publishing geoprocessing services and tasks. This topic is full of information and may be a bit overwhelming at first. You will probably need to visit this topic several times. Nevertheless, start with this topic, then try your hand at one or more of the example services.
Guide to the geoprocessing service examples	This is the overview topic for the geoprocessing service examples that are provided with the ArcGIS tutorial data. There are many examples with information on how to build, publish, and use a service with ArcGIS Desktop. Pick one of the example services, examine it, then publish and use it. After you gain an understanding of one service, try other example services, perhaps modifying them to suit your particular needs.
Guide to related geoprocessing with server topics	This topic provides links to other topics in the documentation system that are relevant to building geoprocessing services.
Input and output data types	When you create a variable in ModelBuilder or define a parameter for a script tool, you provide a data type that defines the values for the variable or parameter such as Feature Class or Linear Unit. There are restrictions on what data types you can use with ArcGIS Server. While data types are discussed in Key concepts for geoprocessing services, this topic provides greater detail.
Creating models for geoprocessing services	Summarizes the rules for creating publishable models.
Preparing map documents containing tool layers	A common method for creating services is to publish a map document containing tool layers. This topic summarizes the steps for creating tool layers.
Defining output symbology for geoprocessing tasks	This topic describes the layer symbology and symbol types supported by clients.
Defining symbology for input feature sets	Feature sets define the symbology to display features that the user creates. This symbology must be compatible with the client. This topic establishes the rules for feature set symbology.
Publishing geoprocessing services	Describes the methods for publishing services using ArcCatalog.
Managing the jobs directory	The jobs directory is where intermediate and output data is written. This topic discusses management of job directories.
Data access considerations for geoprocessing tasks	Any data your tools use must be accessible by all machines in your ArcGIS Server configuration. This topic summarizes the issues you must consider and how to deal with them.
Creating tasks for the UNIX/Linux environment	Your ArcGIS Server configuration may include computers running the UNIX or Linux operating system. While you can only create tools on a Windows platform, they can reside and execute on a UNIX or Linux system. This topic shows you how to build tools on Windows that can execute on UNIX or Linux.
Creating script tools for geoprocessing tasks	Script tools can be published as geoprocessing services. Script tools follow the same rules as model tools. This topic reviews the rules and demonstrates certain aspects of creating script tools suitable for publishing.
Using geoprocessing tasks in Python scripts	Shows how to use a service in a script.
Spatial reference considerations for geoprocessing services	A spatial reference is how ArcGIS describes the map projection and coordinate system of geographic data. Clients can request output data in any spatial reference and ArcGIS Server handles all conversions for you. Occasionally, you may need to output data in a specific spatial reference and this topic shows you how.
Performance tips for geoprocessing services	Tips on how to increase service performance.
Checklist for authoring and publishing geoprocessing services	Reviews all the requirements for authoring and publishing geoprocessing services.

The guide to topics below are for those of you who have little or no experience with ArcGIS Desktop or geoprocessing. Most likely, you have discovered (or heard a rumor) that geoprocessing can help you provide rich GIS functionality in your Web application without having to develop the functionality from scratch. This is true—by building and publishing models and scripts to ArcGIS Server, you can create an infinite number of useful and powerful tools that can be accessed from your Web application. However, you are at a distinct disadvantage if have little or no experience with ArcGIS Desktop or geoprocessing.

The table below guides you to introductory geoprocessing topics.

Topic	Description
What is geoprocessing? A whirlwind tour of geoprocessing	These two topics describe the basic premise of geoprocessing and the main software components (such as the ArcToolbox window and ModelBuilder) that you will interact with.
Geoprocessing framework	This topic is especially relevant if you are a programmer. It describes how geoprocessing is an integrated development environment for automating work.
Geoprocessing tools	Geoprocessing as an integrated development environment for automating work is only one part of the story. This topic is your launch point for understanding geoprocessing tools and their capabilities. There are hundreds of tools that perform a wide variety of functionality, from adding a field to a table to performing sophisticated spatial analysis across multiple datasets.
An overview of using tools An overview of managing toolboxes Working with Results	These topics are all about using tools in the ArcToolbox window.
An overview of models An overview of model concepts and terms An overview of ModelBuilder An overview of controlling the flow of processing	These topics are all about creating models. Models are one way you can create custom tools.
An overview of writing geoprocessing scripts An overview of creating script tools	Scripts are another way you can create custom tools.