Available with Spatial Analyst license.
All Map Algebra statements require input on which to apply the tools and operators (except for CreateNormalRaster and CreateRandomRaster, which have only optional arguments).
- To use input data directly (data on disk, layers, tables, field names), it must be in a quoted string.
# The full path and nmae of the dataset is used outRas = Slope("C:/Data/elevation") # If the layer is in the Table of contents or in your workspace then just the quoted name is needed outRas2 = Slope("elevation")
# In the following statement Population is a field name outRas2 = KernelDensity("inpoints", "Population")
- Existing input data can be assigned to a variable, and the variable can be used in a statement. Variables are not quoted.
inputElevation = "C:/Data/dem" outRas = slope(inputElevation)
- Raster objects can be used as input into subsequent statements. Since a raster object is a variable, it is not quoted.
outSource = ExtractByAttributes("inraster", "Value > 3000") # The output of ExtractByAttributes is used as input to EucDistance outDistance = EucDistance(outSource)
- Result objects can also be used as input into Map Algebra expressions.
# Buffer returns a Result object, which is used here as # input to EucDistance dist = EucDistance(arcpy.Select_analysis("schools", "#", "Pop>2000"))
- Many tools accept multiple inputs for a parameter (multivalue input). Inputs are separated by commas and enclosed in square brackets (denoting a Python list).
outStats = CellStatistics(["inraster1", "inraster2", "inraster3"], "MEAN")