SpatialAnalyst

The SpatialAnalyst and GeoAnalyst objects are threadsafe at ArcGIS 9.2. However, in previous versions, the objects were not threadsafe and running concurrent spatial operations using the same workspace can crash the application. The workaround is to use separate output workspaces for each process or application.

This object includes methods that can be used to perform conditional operations on rasters.

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.

The methods in this object are used to extract data from a raster based on shapes, attributes, and other spatial data.

These methods generalize on zones or smooth zone edges of a raster.

The Euclidean distance functions measure the straight line distance from each cell to the closest source. The Cost Distance function (or cost weighted distance) modifies Euclidean distance by equating distance as a cost factor, which is the cost to travel through any cell.

This object includes methods to perform the following:

These methods can be used to perform rudimentary advection dispersion modeling of constituents in groundwater.

These methods assist in modeling the flow of water and answering questions such as, where did the water come from and where is it going? These hydrologic analysis functions help model the movement of water across a surface and aid in building your understanding of key concepts and terms related to drainage systems and surface processes. In addition, these tools can be used to extract hydrologic information from a digital elevation model (DEM).

In these methods, the value at each location (cell) on the output raster is the result of a function of the input values at the location. One of the methods, for example, evaluates the number of times a set of rasters are greater than another raster, on a cell-by-cell basis.

These methods allow for the exploration of relationships between many different types of attributes. The following are the main types of multivariate analysis:

The 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 moving or a search radius.

Zonal functions take a value raster as input and calculate for each cell some 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.

Map Algebra is the analysis language for ArcGIS Spatial Analyst. It has a syntax that is similar to any algebra. An output raster dataset results from some manipulation of the input. The input can be as simple as a single raster dataset, raster layer, feature dataset, feature layer, or shapefile, and the manipulation can calculate the sine of each of the location's values, or there can be a series of input raster datasets or layers that the manipulation is applied to, such as when adding three raster datasets or raster layers together.

These methods provide access to a full suite of mathematical operators and functions. These operators and functions enable the values in multiple rasters to be combined arithmetically—for example, addition, subtraction, multiplication, and division. In addition, the mathematical manipulation of the values in a single input raster (sine, exponent, power, etcetera), the evaluation of multiple input rasters (Boolean And, Greater Than, combinations, and so on), and the evaluation and manipulation of the values in the binary format (for example, Bitwise And and Bitwise Left Shift) are also supported by these methods.

Defines the relationship between the horizontal cost factor and the horizontal relative moving angle (HRMA). There are several factors to select from (with modifiers) that identify a defined horizontal factor graph. Additionally, a table can be used to create a custom graph. The graphs are used to identify the horizontal factor that will be used to calculate the total cost for moving into a neighboring cell.

Defines the relationship between the vertical cost factor and the vertical relative moving angle (VRMA). There are several factors to select from (with modifiers) that identify a defined vertical factor graph. Additionally, a table can be used to create a custom graph. The graphs are used to identify the vertical factor that will be used to calculate the total cost for moving into a neighboring cell.