Deferred evaluation is an optimization technique where 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 section of Building complex statements. To avoid this potential problem, use appropriate parentheses in the expression so that the execution order of the operators is explicitly defined. When multiple Relational and/or Boolean operators are used consecutively in a single expression, in some cases, it may fail to execute. To change the order of execution, use parentheses.

Therefore, when Boolean operators are used in the same expression as Relational operators, the Boolean operators will be executed first. You can use parentheses to control the execution order.īoolean ( ~, &, ^, |) operators have a higher precedence level than Relational (, >=, =, !=) operators. For more information, see the operator precedence table in Working with operators in Map Algebra. The operator with the highest precedence value will be executed first. When multiple operators are used in an expression, they are not necessarily executed 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 is executed, the resulting raster output will be clipped based on the specified extent. You can easily 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 put the output raster name or the = 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 execute because Python is case sensitive.Īn example of the general format of a Map Algebra expression using using geoprocessing tools is: When typing tool names, be sure to check the tool name syntax.

Arcmap raster calculator