This article offers a step-by-step guide with relevant screenshots and explanations, as well as a short overview of the theory behind this problem. The indentation level (two spaces or four spaces) does not matter as long as it is consistent throughout the code block. Alexandros Voukenas writes about the problem of automatic raster reclassification based on its statistics, using ArcMap’s Model Builder. In Python, proper indentation is part of the syntax. See examples of using the Data Type parameter. For example, if you use the Calculate Value tool to calculate a distance for use as input to the Buffer Distance parameter of the Buffer tool, specify Linear Unit for the Data Type parameter. The Data Type parameter is used in ModelBuilder to help chain the output of the Calculate Value tool with other tools. See examples of using the Code Block parameter. To do this, create a function definition in the Code Block parameter and reference the definition in the Expression parameter. Share your insights with the world or specific groups. Work with smart, data-driven styles and intuitive analysis tools. These variables must be passed to the code block from the expression. Connect people, locations, and data using interactive maps.

You cannot access model variables in the Code Block parameter. To use a variable in the expression, enclose the variable name in percent signs ( %). Variables created in ModelBuilder can be used by this tool, but variables cannot be connected directly to the Expression parameter. See examples of using the Expression parameter. The Code Block parameter cannot be used on its own it must be used in conjunction with the Expression parameter.

Use the Code Block parameter for more complicated expressions, such as multiline calculations or logical operations (if, then). Use the Expression parameter for short one line expressions. Other scripting languages are not supported. The Expression parameter only supports Python expressions. It allows you to create maps, perform spatial analysis and manage data. This tool is intended for use in ModelBuilder, not in Python scripting. ArcGIS Desktop is the foundational piece of the ArcGIS platform for GIS professionals to create, analyse, manage and share geographic information so decision-makers can make intelligent, informed decisions.

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