Available with Spatial Analyst license.
The ArcGIS Spatial Analyst module provides a rich set of spatial analysis and modeling geoprocessing functions for both raster (cell-based) and feature (vector) data.
The capabilities of Spatial Analyst are broken down into categories or groups of related functionality. Knowing the categories will help you identify which particular geoprocessing function to use. The table at the end of this section lists all the available analytical groups with a description of the capabilities offered by the geoprocessing functions in each.
For most geoprocessing functions that output to a raster, the output is a temporary raster object on disk. To make it permanent, you can call the raster object's save method. Based on the workspace and the extension specified, the output format will vary. See Output raster formats and names for more information.
The geoprocessing functions in the ArcPy Spatial Analyst module require the Spatial Analyst extension.
Spatial Analyst geoprocessing functions
The functional categories of Spatial Analyst are identified below.
|Geoprocessing functional category||Description|
The Conditional geoprocessing functions allow you to control the output values based on the conditions placed on the input values. The conditions that can be applied are of two types, those being either queries on the attributes or a condition based on the position of the conditional statement in a list.
With the Density geoprocessing functions, you can calculate the density of input features within a neighborhood around each output raster cell.
The Distance geoprocessing functions allow you to perform analysis that accounts for either straight-line (Euclidean) or weighted distance. Distance can be weighted by a simple cost (friction) surface, or in ways that account for vertical and horizontal restrictions to movement.
The Legacy Distance geoprocessing functions allow you to access the distance analysis geoprocessing functions available in previous releases of ArcGIS. These tools perform analysis that accounts for either straight-line (Euclidean) or weighted distance. Distance can be weighted by a simple cost (friction) surface, or in ways that account for vertical and horizontal restrictions to movement. The Legacy Distance tools utilize the original method of computing distance from earlier releases. To take advantage of the more accurate distance calculations now available, use the distance geoprocessing functions outside of the Legacy toolset.
The Extraction geoprocessing functions allow you to extract a subset of cells from a raster by either the cells' attributes or their spatial location. You can also obtain the cell values for specific locations as an attribute in a point feature class or as a table.
The Generalization analysis geoprocessing functions are used to either clean up small erroneous data in the raster or generalize the data to get rid of unnecessary detail for a more general analysis.
The Groundwater geoprocessing functions can be used to perform rudimentary advection-dispersion modeling of constituents in groundwater flow. They can be applied individually or used in sequence to model and analyze groundwater flow.
The Hydrology geoprocessing functions are used to model the flow of water across a surface. They can be applied individually or used in sequence to create a stream network or delineate watersheds.
The Interpolation geoprocessing functions create a continuous (or prediction) surface from sampled point values that represents some measure, such as the height, concentration, or magnitude (for example, elevation, acidity, or noise level). Surface interpolation geoprocessing functions make predictions from sample measurements for all locations in an output raster dataset, whether or not a measurement has been taken at the location.
The Local geoprocessing functions are those where the value at each cell location on the output raster is a function of the values from all the inputs at that location. With these geoprocessing functions, you can combine the input rasters, calculate a statistic on them, or evaluate a criterion for each cell on the output raster based on the values of each cell from multiple input rasters.
Map Algebra is a way to perform spatial analysis by creating expressions in an algebraic language. With the Raster Calculator geoprocessing function, you can easily create and run Map Algebra expressions that output a raster dataset.
The general Math geoprocessing functions apply a mathematical function to the input. These geoprocessing functions fall into several categories. The arithmetic geoprocessing functions perform basic mathematical operations, such as addition and multiplication. There are geoprocessing functions that perform various types of exponentiation operations, which includes exponentials and logarithms in addition to the basic power operations. The remaining geoprocessing functions are used either for sign conversion or for conversion between integer and floating point data types.
The Bitwise math geoprocessing functions compute on the binary representation of the input values.
The Logical Math geoprocessing functions evaluate the values of the inputs and determine the output values based on Boolean logic. The geoprocessing functions are grouped into four main categories: Boolean, Combinatorial, Logical, and Relational.
The Trigonometric Math geoprocessing functions perform various trigonometric calculations on the values in an input raster.
The Multidimensional Analysis geoprocessing functions allow you to perform analysis on scientific data across multiple variables and dimensions.
Multivariate statistical geoprocessing functions allow the exploration of relationships among many different types of attributes. There are two types of multivariate analysis available: Classification (both Supervised and Unsupervised) and Principal Component Analysis (PCA).
Neighborhood geoprocessing functions create output values for each cell location based on the location value and the values identified in a specified neighborhood. The neighborhood type can be either moving or search radius.
Overlay analysis geoprocessing functions allow you to apply weights to several input layers, combine them into a single output, and subject to specifications of distribution and shape, identify preferred locations within that result. These geoprocessing functions are commonly used for suitability modeling.
The Raster Creation geoprocessing functions generate new rasters in which the output values are based on a constant or a statistical distribution.
The Reclass geoprocessing functions provide a variety of methods that allow you to reclassify or change input cell values to alternative values.
The Segmentation and Classification geoprocessing functions enable you to prepare segmented rasters to create classified raster datasets.
The Solar Radiation analysis geoprocessing functions enable you to map and analyze the effects of the sun over a geographic area for specific time periods.
With the Surface geoprocessing functions, you can quantify and visualize a terrain landform represented by a digital elevation model.
The Zonal geoprocessing functions allow you to perform analysis when the output is a result of computations performed on all cells that belong to each input zone. A zone can be defined as being a single area of a particular value, but it can also be composed of multiple disconnected elements, or regions, all having the same value. Zones can be defined by raster or feature datasets. Rasters must be of integer type, and features must have an integer or string attribute field.