![]() ![]() ![]() The Raster Calculator tool can be used in ModelBuilder, but keep the following details in mind. Operators and tools that support deferred evaluation are included on the raster calculator tool either as a button or in the list of tools provided. Only operators and tools that process on a per-cell basis can take advantage of this capability. Deferred evaluation is an optimization technique in which individual components of an expression are intelligently processed so as to minimize the creation of intermediate datasets on disk. The performance of an operation may be enhanced by the deferred evaluation capabilities of map algebra. For more information, see Complex statement rules. To avoid, use appropriate parentheses in the expression so that the run order of the operators is explicitly defined. When multiple Relational or Boolean operators are used consecutively in a single expression, the expression may fail to run in some cases. To change the order in which the operators are run, use parentheses. Therefore, when Boolean operators are used in the same expression as Relational operators, the Boolean operators will be run first. Use parentheses to control the run order.īoolean ( ~, &, ^, |) operators have a higher precedence level than Relational (, >=, =, !=) operators. For more information, see the operator precedence table in Work with operators in map algebra. The operator with the highest precedence value will be run first. When there are multiple operators in an expression, the operators are not necessarily run in left-to-right order. ![]() To create a raster with cells of a constant value, specify the appropriate Extent and Cell Size environment settings and enter the numerical value into the expression. When the tool runs, the resulting raster output will be clipped based on the specified extent. You can clip a raster dataset by setting the Extent environment and specifying the input raster name in the expression. You do not need to cast input data as a Raster object when using operators.You do not need to include the output raster name or the equal sign ( =) in the expression because the output name is specified in the Output raster parameter.The tool supports the standard map algebra syntax that is used in Python scripting. If the capitalization is incorrect, the expression will be invalid and fail to process because Python is case sensitive.Īn example of the general format of a map algebra expression using geoprocessing tools is: When typing tool names, ensure that the tool name syntax is correct. ![]()
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