Use the raster analysis tools

Note:

Analysis tools are now available in Map Viewer, the modern map-making tool in ArcGIS Online. To learn more, see Perform analysis (Map Viewer).

Licensing

The administrator of your organization must grant you certain privileges for you to perform analysis. To use the raster analysis tools, you need the following privileges:

• Create, update, and delete content
• Publish hosted imagery layers
• Imagery Analysis

These privileges are available with the Professional or Professional Plus user type. If you do not have these privileges, you cannot access the Raster Analysis option as described below.

Some raster analysis tools also require the Publish hosted feature layers privilege, which is automatically turned on when the Imagery Analysis privilege is turned on.

Access the tools

To access and use raster analysis tools in Map Viewer Classic, follow these steps:

1. Open a web map containing the imagery layer or layers you want to analyze in Map Viewer Classic.
2. Click the Analysis button on the map menu bar.
3. In the Perform Analysis pane, click Raster Analysis.

Note:

If the Raster Analysis tools do not appear in the Analysis pane in Map Viewer Classic, you may not be assigned the Professional or Professional Plus user type, or your organization may not have published at least one hosted feature layer. One hosted feature layer must be published before the raster analysis tools are accessible.

Some raster analysis tools also require the Publish hosted feature layers privilege, which is automatically turned on when the Imagery Analysis privilege is turned on.

Explore the Raster Analysis pane

The Raster Analysis pane is illustrated below. This pane contains a number of categories, and each category contains tools. To view the tools in a category, click the expand or collapse button on the left side of the category.

The numbers in the following table correspond to the numbers in the image above:

UI item	Description
	Open the Raster Function Editor window. For details, see Raster Function Editor.
	Open the Browse Raster Function Templates and Custom Web Tools window. For details, see raster functions.
	Open the Analysis Environments dialog box.
	Return to the Perform Analysis pane.
	Get help about the category.
	Expand the category to view the tools it contains.

Use the analysis environments

Use the Analysis Environments button to access the raster and imagery processing environments that apply to all raster analysis tools. When you open the Analysis Environments window from the Raster Analysis pane, you can modify the settings for the output coordinate system, processing extent, snap raster, cell size, and mask.

The following table describes the options in the Analysis Environments window:

Analysis Environment options	Description
Output coordinate system	Specifies the coordinate system of the result imagery layer. The following options are available: Same as input—The result of the analysis will be in the same coordinate system as the input. This is the default. As specified—The result of the analysis will be in the coordinate system you choose. When this option is selected, click the Select Coordinate System button and choose from a list of known coordinate systems, or provide the spatial reference WKID in the text box. Layer <name>—The result of the analysis will be in the same coordinate system as an existing layer you choose in your web map.
Extent	Specifies the extent or boundary that will be used during the analysis process. All pixels or cells that are completely within or that intersect the specified extent will be used in the analysis. The following options are available: Default—The extent used for analysis is provided by the tool. As specified—The extent is defined by the coordinates you provide. Layer <name>—The extent used to process the analysis will be the same as the spatial extent of an existing layer you choose in your web map.
Snap Raster	Adjusts the extent of the output raster layer so it matches the cell alignment of the specified Snap Raster layer.
Cell size	Specifies the cell size or resolution that will be used to create the output raster layer in a raster analysis. The default output resolution is determined by the largest cell size of the input raster layer. The following options are available: Minimum of Inputs—Use the smallest cell size of all input layers. Maximum of Inputs—Use the largest cell size of all input layers. This is the default. As specified—Specify a numeric value to set the cell size. If this is selected, the default value is 1. Layer <name>—Set the cell size to the raster layer chosen.
Mask	The layer that will be used to define the area of interest for the analysis. Only those cells that fall within the analysis mask will be considered in the analysis operation. The mask can be either a raster or a feature layer. If the analysis mask is a raster, all cells that have a value will be considered to define the mask. Cells in a mask raster that are NoData will be considered to be outside the mask and will be NoData in the analysis result layer. If the analysis mask is a feature layer, it will be internally converted to a raster. For this reason, ensure that Cell Size and Snap Raster are set appropriately for the analysis.

When you open the Analysis Environments window from a raster analysis tool pane, you may see additional analysis environments. Some raster analysis tools honor several of the analysis environments listed in the table below. Because not all tools honor all the environments, they are accessed from the individual tools instead of from the Raster Analysis pane.

Analysis Environment options	Description
Resampling method	Specifies how pixel values will be interpolated when transforming a raster dataset. This environment is used when the input and output do not line up, when the pixel size changes, when the data is shifted, or a combination of these situations. The following options are available: Nearest neighborhood—Used primarily for discrete data, such as a land-use classification, since it does not create new pixel values. This method is also appropriate for continuous data when you want to preserve the original reflectance values in imagery for accurate multispectral analysis. It is the most efficient in terms of processing time but may introduce small positional errors in the output image. The output image may be offset by up to half a pixel, which may cause the image to have discontinuities and a jagged appearance. Bilinear interpolation—This method is most appropriate for continuous data. It performs a bilinear interpolation and determines the new value of a cell based on a weighted distance average of the four nearest input cell centers. It creates an output image that is smoother in appearance than Nearest neighborhood but alters the reflectance values, which results in blurring or loss of image resolution. Cubic convolution—Suitable for continuous data. This method performs a cubic convolution and determines the new value of a cell based on fitting a smooth curve through the 16 nearest input cell centers. The result is geometrically less distorted than the raster achieved with Nearest neighborhood and sharper than Bilinear interpolation. In some cases, it can result in output pixel values outside the range of input cell values. If this is unacceptable, use the Bilinear interpolation method instead. Cubic convolution is computationally intensive and takes longer to process.
Processor type	Specifies whether the analysis will be run using the CPU or GPU. If the Processor type environment is empty, the tool uses CPU to process the data. The following options are available: CPU—CPU will be used for processing. CPU processing can be parallelized across multiple cores and instances, as handled by the Parallel processing factor. GPU—GPU will be used for processing. GPUs are effective at graphics and image processing, where their highly parallel structure makes them efficient in processing large blocks of data in a repetitive manner. The raster analysis tools that honor this environment can distribute its job across GPU instances at multiple raster analysis server machines, as handled by the Parallel processing factor environment.
Recycle interval of processing workers	The number of image sections that will be processed before restarting worker processes to prevent potential failures in long-running processes. The default value is 0.
Parallel processing factor	The number of raster processing service instances that can be used for processing the data. If the tool doesn't honor the Processor type environment, or if the Processor type environment is set to CPU, the Parallel processing factor environment controls raster processing CPU service instances. If the Processor type environment is set to GPU, the Parallel processing factor environment controls the number of raster processing GPU instances. By setting the Parallel processing factor value, you can request the number of parallel workers that the raster analytics image server uses to process one raster analysis task. However, if the total number of parallel processes exceeds the maximum number of raster processing (CPU or GPU) service instances, the additional parallel processes will be queued. If no Parallel processing factor value is specified, which is the default, the tool will use 80 percent of the maximum number of raster processing service instances. Either an integer number or a percentage can be provided as the parallel processing factor.
Number of retries on failures	The number of retries the same worker process will attempt when there is random failure processing a particular job. The default value is 0.

Work with a tool pane

To open a raster analysis tool pane, click the tool button. This opens the tool's pane as illustrated below with the Monitor Vegetation tool.

The numbers in the following table correspond to the numbers in the image above:

UI item	Description
	Open the Analysis Environments dialog box.
	Close the tool pane without running the analysis and return to the Raster Analysis pane.
	Get help about a parameter.
	The result of running the analysis is saved to Content using this name.
	Specify a folder in Content where the result will be saved.
	Show the number of credits that will be used to run the analysis.
	If checked, only the data visible in the current map will be analyzed.

Note:

Before running an analysis tool in ArcGIS Online, you can use the credit estimator to calculate the expected number of credits that will be used. If your organization has enabled credit budgeting and the expected number of credits exceeds the number of credits allocated to you, ArcGIS Online displays an error message. For more on credit allocation and consumption, see Understand credits.

Each tool has a different set of parameters. You can view help for a parameter by clicking the help button next to the parameter as illustrated above. All tools have a Result layer name parameter where the results of running the analysis are written. You can change this name or use the default value.

Use current map extent

It is recommended that you always check Use current map extent and that you zoom in to the area you want analyzed. Doing so limits the amount of imagery or raster pixels the tool will include when performing analysis as well as limiting the number of credits used by the tool. If you uncheck Use current map extent, the entire input imagery layer will potentially be analyzed, and credits used by the tool will be based on the size of the imagery and complexity of the analysis.

Note:

The Use current map extent parameter is unchecked by default when the Processing Extent environment is set. Checking Use current map extent will override the Processing Extent value.