The Geomorphon Landforms tool calculates the geomorphon pattern of each cell of an input surface raster and classifies them into common landform types.
The output is a hosted imagery layer.
Learn how Geomorphon Landforms works
Examples
Some example applications of this tool include the following:
- Given an elevation raster, find valleys to validate the location of streams.
- Given an elevation raster, find the location of ridges for zoning purposes.
Usage notes
Geomorphon Landforms includes configurations for input layer, analysis settings, and the result layers.
Input layer
The Input layer group includes the following parameters:
Input surface raster is the surface raster that will be used for calculation.
If a z-unit is available in the vertical coordinate system of the input raster, it will be applied automatically. If the z-unit is undefined, Meter will be used by default.
Analysis settings
The Analysis settings group includes the following parameters:
Distance units specifies the distance unit that will be used for the Search distance and Skip distance parameters. Distance will be measured in the specified unit or number of cells. The default is Cells.
If the cell size hasn’t been explicitly specified as the parameter value, it is derived from the Cell Size environment if it has been specified. If the parameter cell size or the environment cell size has not been specified, the default output cell size is the cell size of the input surface raster dataset.
Search distance specifies the distance away from the target cell that defines the radius of the area that will be used to identify the geomorphon pattern.
The default value is 10 cells. Use a search distance value that matches the type and size of the landforms that you want to classify.
Smaller values of the Search distance parameter will result in small analysis areas where large landscape features may be broken into smaller features and classified accordingly. Larger values of the Search distance parameter will result in a large analysis area, which may provide more information about the surrounding terrain and improve the ability to classify a target cell as part of a large landscape feature. At the same time, a large value may omit small landscape features. For example, a cell may be classified as flat in a small analysis area (a small Search distance value) but may be classified as a valley in a broader analysis area (a large Search distance value).
Skip distance specifies the distance away from the target cell where the analysis area starts. Neighboring cells that fall within this distance will be skipped and won't contribute to identification of the geomorphon pattern.
The classification of each individual cell is determined by assessing the neighboring cells within the skip distance from the target cell center.
Angle threshold specifies the threshold (in degrees) below which the target cell will be classified as flat. It is the difference between the line-of-sight angles below which the visible surrounding area will be considered flat.
When choosing a value for Angle threshold, consider the analysis cell size. For example, a 1-degree threshold means several meters of elevation difference for an input raster with a large cell size. A large threshold will result in more areas identified as flat.
Z unit specifies the linear unit of vertical z-values.
It is defined by a vertical coordinate system if one exists. If a vertical coordinate system does not exist, define the z-unit from the unit list to ensure correct geodesic computation. The default is Meter. The options are Inch, Foot, Yard, Mile US, Nautical mile, Millimeter, Decimeter, Centimeter, Meter, and Kilometer.
Result layers
The Result layers group includes the following parameters:
Output landforms raster name is the name of the output raster containing the landform classification result ofthe landforms.
The name must be unique. If a layer with the same name already exists in your organization, the tool will fail, and you will be prompted to use a different name.
The Optional layers includes the Output geomorphons raster name which is the name of the output raster containing the geomorphon patterns result.
The name must be unique. If a layer with the same name already exists in your organization, the tool will fail, and you will be prompted to use a different name.
- Output layer type specifies the type of raster output that will be created. The output can be either a tiled imagery layer or a dynamic imagery layer.
- Save in folder specifies the name of a folder in My content where the result will be saved.
Environments
Analysis environment settings are additional parameters that affect a tool's results. You can access the tool's analysis environment settings from the Environment settings parameter group.
This tool honors the following analysis environments:
- Output coordinate system
- Geographic transformations
- Processing extent
Note:
The default processing extent for raster analysis tools and raster functions is Display extent. This default is different from other types of analysis.
- Snap raster
- Cell size
- Mask
Credits
This tool consumes credits.
Use Estimate credits to calculate the number of credits that will be required to run the tool. For more information, see Understand credits for spatial analysis.
Output
The Output landforms raster name is a raster representing the result of the geomorphon classification into 10 landform types: flat, peak, ridge, shoulder, spur, slope, hollow, footslope, valley, and pit.
NoData cells in the input surface raster are ignored, and those cells are assigned NoData in the output.
The output is of type integer.
The Output geomorphons raster name is a raster representing a unique identifier of the geomorphon pattern. It can be used to classify geomorphon into landforms using a different lookup table.
NoData cells in the input surface raster are ignored, and those cells are assigned NoData in the output.
The output is of type integer.
Usage requirements
This tool requires the following user type and configurations:
- Professional or Professional Plus user type
- Publisher, Facilitator, or Administrator role, or an equivalent custom role with the Imagery Analysis privilege
References
- Jasiewicz, Juroslav and Tomasz F. Stepinski. 2013. "Geomorphons - a pattern recognition approach to classification and mapping of landforms." Geomorphology Volume 182, January 15, pp. 147-56. https://doi.org/10.1016/j.geomorph.2012.11.005
Resources
Use the following resources to learn more:
- How Geomorphon Landforms works
- Geomorphon Landforms in ArcGIS REST API
- Geomorphon Landforms in ArcGIS Pro with the Spatial Analyst extension