Introduction

Various messages are returned during the execution of ArcGIS geoprocessing tools and functions. These messages can be informational in nature or indicate warning or error conditions that can result in the tool not creating the expected output or in outright failure of the tool to execute. These messages do not appear as message boxes. Instead, you will need to retrieve them using various ArcPy functions. To this point in the book, we have ignored the existence of these messages, warnings, and errors. This is mainly due to the fact that I wanted you to concentrate on learning some basic concepts, without adding the extra layer of code complexity that is necessary for creating robust geoprocessing scripts that can handle error situations gracefully. That being said, it's now time that you learn how to create the geoprocessing and Python exception handling structures that will enable you to create versatile geoprocessing scripts. These scripts can handle messages that indicate...