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Description
Class Summary  

Abs  Calculates the absolute value of cells in a raster. 
ACos  Calculates the inverse cosine of cells in a raster. 
ACosH  Calculates the inverse hyperbolic cosine of cells in a raster. 
Aggregate  Generates a reduced resolution version of a raster. 
AreaSolarRadiation  Derives incoming solar radiation from a raster surface. 
ASin  Calculates the inverse sine of cells in a raster. 
ASinH  Calculates the inverse hyperbolic sine of cells in a raster. 
Aspect  Derives aspect from a raster surface. 
ATan  Calculates the inverse tangent of cells in a raster. 
ATan2  Calculates the inverse tangent (based on x,y) of cells in a raster. 
ATanH  Calculates the inverse hyperbolic tangent of cells in a raster. 
BandCollectionStats  Calculates the statistics for a set of raster bands. 
Basin  Creates a raster delineating all drainage basins. 
BitwiseAnd  Performs a Bitwise And operation on the binary values of two input rasters. 
BitwiseLeftShift  Performs a Bitwise Left Shift operation on the binary values of two input rasters. 
BitwiseNot  Performs a Bitwise Complement operation on the binary value of an input raster. 
BitwiseOr  Performs a Bitwise Or operation on the binary values of two input rasters. 
BitwiseRightShift  Performs a Bitwise Right Shift operation on the binary values of two input rasters. 
BitwiseXOr  Performs a Bitwise Exclusive Or operation on the binary values of two input rasters. 
BlockStatistics  Calculates statistics for a nonoverlapping neighborhood. 
BooleanAnd  Performs a Boolean And operation on the cell values of two input rasters. 
BooleanNot  Performs a Boolean complement (NOT) operation on the cell values of two input rasters. 
BooleanOr  Performs a Boolean Or operation on the cell values of two input rasters. 
BooleanXOr  Performs a Boolean Exclusive Or operation on the cell values of two input rasters. 
BoundaryClean  Smoothes the boundary between zones by expanding and shrinking it. 
CellStatistics  Calculates a percell statistic from multiple rasters. 
ClassProbability  Creates probability layers for each class in a signature file. 
CombinatorialAnd  Performs a Combinatorial And operation on the cell values of two input rasters. 
CombinatorialOr  Performs a Combinatorial Or operation on the cell values of two input rasters. 
CombinatorialXOr  Performs a Combinatorial Exclusive Or operation on the cell values of two input rasters. 
Combine  Combines multiple rasters so a unique output value is assigned to each unique combination of input values. 
ConTool  Performs a conditional if/else evaluation on each of the input cells of an input raster. 
Contour  Creates contours or isolines from a raster surface. 
ContourList  Creates contours or isolines based on a list of contour values. 
ContourWithBarriers  Creates contours from a raster surface. 
Corridor  Calculates the sum of accumulative costs for two input accumulative cost rasters. 
Cos  Calculates the cosine of cells in a raster. 
CosH  Calculates the hyperbolic cosine of cells in a raster. 
CostAllocation  Calculates for each cell its nearest source based on the least accumulative cost over a cost surface. 
CostBackLink  Defines the neighbor that is the next cell on the least accumulative cost path to the nearest source. 
CostDistance  Calculates the least accumulative cost distance for each cell to the nearest source over a cost surface. 
CostPath  Calculates the leastcost path from a source to a destination. 
CreateConstantRaster  Creates a raster of a constant value within the Analysis window. 
CreateNormalRaster  Creates a raster of random values with a normal distribution on a cellbycell basis within the Analysis window. 
CreateRandomRaster  Creates a raster of random floating point values between 0 and 1 on a cellbycell basis within the Analysis window. 
CreateSignatures  Creates an ASCII signature file of classes defined by input sample data and a set of raster bands. 
Curvature  Calculates the curvature of a raster surface, optionally including profile and plan curvature. 
CutFill  Calculates the volume and area of cut and fill locations. 
DarcyFlow  Calculates the groundwater volume balance residual and other outputs for steady flow in an aquifer. 
DarcyVelocity  Calculates the groundwater seepage velocity vector (direction and magnitude) for steady flow in an aquifer. 
Dendrogram  Constructs a tree diagram showing attribute distances between sequentially merged classes in a signature file. 
Diff  Determines which values from the first input are logically different from the values of the second input on a cellbycell basis within the Analysis window. 
Divide  Divides the values of two rasters on a cellbycell basis. 
EditSignatures  Edits and updates a signature file by merging, renumbering, and deleting class signatures. 
EqualTo  Performs a relational equalto operation on two inputs on a cellbycell basis within the Analysis window. 
EqualToFrequency  Evaluates the number of times a set of rasters is equal to another raster on a cellbycell basis. 
EucAllocation  Calculates, for each cell, the nearest source based on Euclidean distance. 
EucDirection  Calculates, for each cell, the direction, in degrees, to the nearest source. 
EucDistance  Calculates, for each cell, the Euclidean distance to the closest source. 
Exp  Calculates the base e exponential of cells in a raster. 
Exp10  Calculates the base 10 exponential of cells in a raster. 
Exp2  Calculates the base 2 exponential of cells in a raster. 
Expand  Expands specified zones of a raster by a specified number of cells. 
ExtractByAttributes  Extracts the cells of a raster based on a logical query. 
ExtractByCircle  Extracts the cells of a raster based on a circle. 
ExtractByMask  Extracts the cells of a raster that correspond to the areas defined by a mask. 
ExtractByPoints  Extracts the cells of a raster based on a set of points. 
ExtractByPolygon  Extracts the cells of a raster based on a polygon. 
ExtractByRectangle  Extracts the cells of a raster based on a rectangle. 
ExtractValuesToPoints  Extracts the cell values of a raster based on a set of points. 
Fill  Fills sinks in a surface raster to remove small imperfections in the data. 
Filter  Performs a preset focal filter on a raster. 
Float  Converts each cell value of a raster into a floatingpoint representation. 
FlowAccumulation  Creates a raster of accumulated flow to each cell. 
FlowDirection  Creates a raster of flow direction from each cell to its steepest downslope neighbor. 
FlowLength  Calculates distance or weighted distance along a flow path. 
FocalFlow  Determines the flow of the values in the input raster within each cell's immediate neighborhood. 
FocalStatistics  Calculates a statistic on a raster over a specified neighborhood. 
GreaterThan  Returns 1 for cells where the first raster is greater than the second raster and 0 for cells if it is not. 
GreaterThanEqual  Returns 1 for cells where the first raster is greater than or equal to the second raster and 0 if it is not. 
GreaterThanFrequency  Evaluates the number of times a set of rasters is greater than another raster on a cellbycell basis. 
HighestPosition  Determines the position of a raster with the maximum value in a set of rasters. 
HillShade  Computes hillshade values for a raster surface by considering the illumination angle and shadows. 
Idw  Interpolates a surface from points using an inverse distance weighted (IDW) technique. 
InList  Determines which values from the first input are contained in the other inputs, on a cellbycell basis within the Analysis window. 
Int  Converts each cell value of a raster to an integer by truncation. 
IsNull  Returns 1 if the input value is NoData and 0 for cells that are not, on a cellbycell basis within the Analysis window. 
IsoCluster  Uses an isodata clustering algorithm to determine the characteristics of the natural groupings of cells in multidimensional attribute space and stores the results in an output ASCII signature file. 
KernelDensity  Calculates a magnitude per unit area from point or polyline features using a kernel function to fit a smoothly tapered surface to each point or polyline. 
Kriging  Interpolates a surface from points using kriging. 
LessThan  Returns 1 for cells where the first raster is less than the second raster and 0 if it is not. 
LessThanEqual  Returns 1 for cells where the first raster is less than or equal to the second raster and 0 where it is not. 
LessThanFrequency  Evaluates the number of times a set of rasters is less than another raster on a cellbycell basis. 
LineDensity  Calculates a magnitude per unit area from polyline features that fall within a radius around each cell. 
LineStatistics  Calculates a statistic on the attributes of lines in a circular neighborhood around each output cell. 
Ln  Calculates the natural logarithm (base e) of cells in a raster. 
Log10  Calculates the base 10 logarithm of cells in a raster. 
Log2  Calculates the base 2 logarithm of cells in a raster. 
Lookup  Creates a new raster by looking up values found in another field in the table of the input raster. 
LowestPosition  Determines the position of a raster with the minimum value in a set of rasters. 
MajorityFilter  Replaces cells in a raster based on the majority of their contiguous neighboring cells. 
Minus  Subtracts the value of the second input raster from the value of the first input raster on a cellbycell basis within the Analysis window. 
MLClassify  Performs a maximum likelihood classification on a set of raster bands. 
Mod  Finds the remainder of the first raster when divided by the second raster on a cellbycell basis. 
MultiOutputMapAlgebra  Runs an expression built with the Map Algebra language. 
NaturalNeighbor  Interpolates a surface from points using a natural neighbor technique. 
Negate  Changes the sign (multiplies by 1) of the cell values of the input raster on a cellbycell basis within the Analysis window. 
Nibble  Replaces cells of a raster corresponding to a mask with the values of the nearest neighbors. 
NotEqual  Returns 1 for cells where the first raster is not equal to the second raster and 0 for cells where it is equal. 
ObserverPoints  Identifies exactly which observer points are visible from each raster surface location. 
Over  Returns those values from the first input that are nonzero; otherwise, returns the value from the second input on a cellbycell basis within the Analysis window. 
ParticleTrack  Calculates the path of a particle through a velocity field, returning an ASCII file of particle tracking data and, optionally, a coverage of track information. 
PathAllocation  Calculates the nearest source for each cell based on the least accumulative cost over a cost surface, while accounting for surface distance and horizontal and vertical cost factors. 
PathBackLink  Defines the neighbor that is the next cell on the least accumulative cost path to the nearest source, while accounting for surface distance and horizontal and vertical cost factors. 
PathDistance  Calculates, for each cell, the least accumulative cost distance to the nearest source, while accounting for surface distance and horizontal and vertical cost factors. 
Pick  Assigns output values using one of a list of rasters determined by the value of an input raster. 
Plus  Adds the values of two rasters on a cellbycell basis within the Analysis window. 
PointDensity  Calculates a magnitude per unit area from point features that fall within a neighborhood around each cell. 
PointsSolarRadiation  Derives incoming solar radiation for specific locations in a point feature class or location table. 
PointStatistics  Calculates a statistic on points over a specified neighborhood outputting a raster. 
Popularity  Determines the value in an argument list that is at a certain level of popularity on a cellbycell basis within the Analysis window. 
PorousPuff  Calculates the timedependent, twodimensional concentration distribution in mass per volume of a solute introduced instantaneously and at a discrete point into a vertically mixed aquifer. 
Power  Raises the cells in a raster to the power of the values found in another raster. 
PrincipalComponents  Performs principal components analysis on a set of raster bands. 
Rank  Returns the value of a set of rasters based on a rank level specified by another raster. 
ReclassByASCIIFile  Reclassifies or changes the values of the input cells of a raster using an ASCII remap file. 
ReclassByTable  Reclassifies or changes the values of the input cells of a raster using a remap table. 
Reclassify  Reclassifies (or changes) the values in a raster. 
RegionGroup  For each cell in the output, Regiongroup records the identity of the connected region to which that cell belongs. 
RoundDown  Returns the next lower whole number for each cell in a raster. 
RoundUp  Returns the next higher whole number for each cell in a raster. 
Sample  Creates a table that shows the values of cells from a raster, or set of rasters, for defined locations. 
SetNull  Returns NoData if a conditional evaluation is true and returns the value specified by another raster if it is false, on a cellbycell basis. 
Shrink  Shrinks the selected zones by a specified number of cells. 
Sin  Calculates the sine of cells in a raster. 
SingleOutputMapAlgebra  Runs a single expression built with the Map Algebra language. 
SinH  Calculates the hyperbolic sine of cells in a raster. 
Sink  Creates a raster identifying all sinks or areas of internal drainage. 
Slice  Slices a range of values of the input cells of a raster by zones of equal interval, equal area, or by natural breaks. 
Slope  Identifies the rate of maximum change in zvalue from each cell. 
SnapPourPoint  Snaps pour points to the cell of highest flow accumulation within a specified distance. 
SolarRadiationGraphics  Derives raster representations of a hemispherical viewshed, sunmap, and skymap, which are used in the calculation of direct, diffuse, and global solar radiation. 
Spline  Interpolates a surface from points using a minimum curvature spline technique. 
SplineWithBarriers  Interpolates a surface, using barriers, from points using a minimum curvature spline technique. 
Square  Calculates the square of cells in a raster. 
SquareRoot  Calculates the square root of cells in a raster. 
StreamLink  Assigns unique values to sections of a raster linear network between intersections. 
StreamOrder  Assigns a numeric order to segments of a raster representing branches of a linear network. 
StreamToFeature  Converts a raster representing a linear network to features representing the linear network. 
TabulateArea  Calculates crosstabulated areas between two datasets. 
Tan  Calculates the tangent of cells in a raster. 
TanH  Calculates the hyperbolic tangent of cells in a raster. 
Test  A logical expression used to perform a Boolean evaluation of the input raster. 
Thin  Thins rasterized linear features by reducing the number of cells representing the width of the features. 
Times  Multiplies the values of two rasters on a cellbycell basis. 
TopoToRaster  Interpolates a hydrologically correct surface from point, line, and polygon data. 
TopoToRasterByFile  Interpolates a hydrologically correct surface from point, line, and polygon data using parameters specified in a file. 
Trend  Interpolates a surface from points using a trend technique. 
Viewshed  Determines the raster surface locations visible to a set of observer features. 
Watershed  Determines the contributing area above a set of cells in a raster. 
WeightedOverlay  Overlays several rasters using a common measurement scale and weights each according to its importance. 
WeightedSum  Overlays several rasters multiplying each by their given weight and summing them together. 
ZonalFill  Fills zones using the minimum cell value from a weight raster along the zone boundary. 
ZonalGeometry  Calculates for each zone in a dataset the specified geometry measure (area, perimeter, thickness, or the characteristics of ellipse). 
ZonalGeometryAsTable  Calculates for each zone in a dataset the geometry measuresfor example, area, perimeter, thickness, and the characteristics of ellipseand reports the results as a table. 
ZonalStatistics  Calculates statistics on values of a raster within the zones of another dataset. 
ZonalStatisticsAsTable  Summarizes the values of a raster within the zones of another dataset and reports the results to a table. 
ArcGIS Spatial Analyst provides a rich set of tools to perform cellbased (raster) analysis. Of the three main types of GIS data (raster, vector, and TIN), the raster data structure provides the most comprehensive modeling environment for spatial analysis.
Cellbased systems divide the world into discrete uniform units called cells, based on a grid structure. Each cell represents a certain specified portion of the earth, such as a square kilometer, hectare, or square meter. Cells are given values that correspond to the features or characteristics that are located at or describe the locations they represent, such as an elevation value, soil type, or residential classification. In a cellbased system, geographic location is not defined as an attribute but is inherent in the storage structure, known as the locational perspective.
The locational perspective allows ArcGIS Spatial Analyst to store continuous data—for example, elevation, oil concentration, and sound—more effectively. In continuous data, each location has a quantity, magnitude, or intensity assigned to it, and the values are relative to one another. The locational perspective also allows for greater diversity in spatial analysis for both discrete—for example, land use and vegetation type—and continuous data, which will become apparent in the wide variety of discussions accompanying each toolset.
The following table lists the available toolsets in ArcGIS Spatial Analyst and gives a brief description of each.
Name  Description 

Conditional Toolset  The conditional tools allow for control of the output values based on conditions placed on the input values. The conditions that can be applied are either attribute queries or are based on the position of the conditional statement in a list. A simple attribute query might be, if a cell value is greater than five, multiply it by ten; otherwise, assign a value of one to the location. 
Density Toolset  By calculating density, you spread point values over a surface. The magnitude at each sample location (line or point) is distributed throughout a landscape, and a density value is calculated for each cell in the output raster. For example, density analysis will take population counts assigned to town centers and distribute the people throughout the landscape more realistically. 
Distance Toolset  There are two main ways to perform distance analysis in ArcGIS Spatial Analyst: Euclidean distance and cost distance. The Euclidean distance functions measure straightline distance from each cell to the closest source (the source identifies the objects of interest, such as wells, roads, or a school). The cost distance functions (or cost weighted distance) modify Euclidean distance by equating distance as a cost factor, which is the cost to travel through any given cell. For example, it may be shorter to climb over the mountain to the destination, but it is faster to walk around it. 
Extraction Toolset  The extraction tools allow you to extract a subset of cells by either the cells' attributes or their spatial location. Extracting cells by attribute is accomplished through a where clause. For example, your analysis may require an extraction of cells higher than 100 meters in elevation from an elevation raster. You can also extract by a specified shape. For example, you can extract all cells that fall inside, or outside, a specified circle, rectangle, or polygon. 
Generalization Toolset  Sometimes a raster dataset contains data that is erroneous or irrelevant to the analysis at hand or is more detailed than you need. For instance, if a raster dataset was derived from the classification of a satellite image, it may contain many small and isolated areas that are misclassified. The generalization functions assist with identifying such areas and automate the assignment of more reliable values to the cells that make up the areas. 
Groundwater Toolset  The groundwater tools can be used to perform rudimentary advection–dispersion modeling of constituents in groundwater. 
Hydrology Toolset  Hydrology functions simulate the flow of water over an elevation surface and create either a stream network or a watershed. 
Interpolation Toolset  Surface interpolation functions create a continuous (or prediction) surface from sampled point values. The continuous surface representation of a raster dataset represents height, concentration, or magnitude—for example, elevation, pollution, or noise. Surface interpolation functions make predictions from sample measurements for all locations in a raster dataset whether or not a measurement has been taken at the location. 
Local Toolset  In a local function, the value at each location on the output raster is a function of the input values at the location. When computing a local function, you can combine the input rasters, calculate a statistic, or evaluate a criteria for each cell in an output raster based on the values of each cell from multiple input rasters. For example, you can find the mean precipitation for a tenyear period or find how many years the precipitation exceeded 0.5 meters. 
Map Algebra Toolset  Map Algebra is the analysis language for ArcGIS Spatial Analyst. It is a simple syntax similar to algebraic syntax. For example, to create a slope map from an elevation surface, use the following command: outslope–slope(elevation). Most ArcGIS Spatial Analyst functions can be accessed through Map Algebra. 
Math Toolset  ArcGIS Spatial Analyst provides a full suite of mathematical operators and functions. These operators and functions allow for the arithmetic combining of the values in multiple rasters, the mathematical manipulation of the values in a single input raster, the evaluation of multiple input rasters, or the evaluation and manipulation of values in the binary format. 
Multivariate Toolset  Multivariate statistical analysis allows for the exploration of relationships between many different types of attributes. There are two main types of multivariate analysis available in ArcGIS Spatial Analyst: (1) supervised and unsupervised classification, and (2) principal component analysis (PCA). A third multivariate analysis, regression, is available in ArcGrid Workstation. Accompanying these analyses are a series of tools to evaluate each step in the analysis process. These tools can be used, for example, to predict the biomass (the dependent variable) at each location given the quantities of precipitation, soil type, aspect, and temperature (the independent variables). 
Neighborhood Toolset  Neighborhood functions create output values for each cell location based on the value for the location and the values identified in a specified neighborhood. The neighborhood can be of two types: moving or search radius. Moving neighborhoods can be either overlapping or nonoverlapping. Overlapping neighborhood functions, also referred to as focal functions, generally calculate a specified statistic within the neighborhood. For example, you may want to find the mean or maximum value in a 3x3 neighborhood. The nonoverlapping neighborhood functions, or block functions, allow for statistics to be calculated in a specified nonoverlapping neighborhood. Search radius functions perform various calculations based on what is within a specified distance from point and linear features. 
Overlay Toolset  A common spatial analysis query is to identify the suitability of each cell location relative to specific criteria. The criteria can be relative costs, preferences, or risks. Suitability models answer questions such as, Where is the best location to construct a house? What is the cheapest route to build a road? and Which areas should be conserved for deer habitat? The Weighted Overlay tool allows you to easily reclassify your data, weight the datasets, and combine them to create a suitability map. 
Raster Creation Toolset  The raster creation functions create new rasters in which the output values are based on a constant or a statistical distribution. The Create Constant Raster tool creates an output raster of constant values within a specified map extent and cell size. The Create Normal Raster tool assigns values to an output raster so the values produce a normal distribution. The Create Random Raster (or Map Algebra Rand) tool randomly assigns values to cells on an output raster. 
Reclass Toolset  Reclassifying your data simply means replacing input cell values with new output cell values. There are many reasons why you might want to reclassify your data. Some of the most common reasons are: (1) to replace values based on new information, (2) to group certain values together, (3) to reclassify values to a common scale (for example, for use in a suitability analysis or for creating a cost raster for use in the Cost Distance tool), and (4) to set specific values to NoData or to set NoData cells to a value. There are several approaches to reclassify your data: by individual values, by ranges, by intervals or area, or through an alternative value. 
Solar Radiation Toolset  Using the solar radiation analysis tools, you can calculate incoming solar insolation (global, direct, and diffuse radiation) across a geographic area or for specific point locations. Using an input surface DEM, you can determine the amount of radiant energy that is received from the sun across a landscape for a given period of time. 
Surface Toolset  With the surface analysis tools, you can gain information by producing a new dataset that identifies a specific pattern within an original dataset. Patterns that were not readily apparent in the original surface can be derived, such as contours, angle of slope, steepest downslope direction (aspect), shaded relief (hillshade), and viewshed. 
Zonal Toolset  Zonal functions take a value raster as input and calculate a function or statistic using the value for each cell and all cells belonging to the same zone. The zonal functions are grouped by how the zones are specified: by a single input value raster or by a second zone raster. You can use the zonal tools to locate the number of endangered species (the value raster) within each parcel (the zone raster) or to find the area or perimeter of each zone in a raster. 


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