Available with Image Server
The Locate Regions tool identifies the best regions in the input raster that meet specified size requirements and spatial constraints.
The output is a hosted imagery layer.
Learn more about how Locate Regions works
Examples
The Locate Regions tool can be used in the following scenarios:
- Identify the most preferred deer habitat to conserve. Eight habitat patches (regions) are needed to maintain a viable population, and each region must be approximately 50 contiguous acres. To support breeding opportunities within the herd, the regions should be close enough to one another so that they can be feasibly connected through wildlife corridors.
- Identify the best locations to extract timber for a logging operation. To be financially viable, the areas (regions) to be logged must be at least 250 contiguous acres and each region must be within one mile from another.
- Identify the ideal location for a new shopping center. The shopping center requires the best 60 acres; however, for construction purposes, the area must be contiguous and the shape of the building site (region) should be as compact as possible.
Usage notes
Locate Regions includes configurations for input layers, locate settings, evaluation criteria, region requirements, region growth specifications, and the result layer.
Input layers
The Input layers group includes the following parameters:
Input raster is the utility raster from which the regions will be derived.
The higher the value in the input raster, the greater the utility.
The raster can be of either integer or floating-point type.
The Optional regions layer group includes Input raster or feature of existing regions, which identifies where regions already exist.
The input can be a raster or feature. You can choose a layer using the Layer button, or use the Draw input features button to create a sketch layer to use as the input. If the input is a raster, any location in the raster with a valid value is considered already allocated. All other locations are set to NoData. For feature inputs, a count of features is displayed below the layer name. The count includes all features in the layer, except features that have been removed using a filter. Environment settings, such as Processing extent, are not reflected in the feature count.
In the parameterized region-growing (PRG) algorithm, no region will grow from any location identified as an existing region. Existing regions will be used in the growth and evaluation of the Minimum distance between regions and Maximum distance between regions parameters, as described in the corresponding parameter descriptions below.
Locate settings
The Locate settings group includes the following parameters:
Total area specifies the total amount of area for all regions.
If no value is provided for this parameter, the calculation is based on 10 percent of the input cells within the processing extent.
Area units specifies the area units used for the Total area, Region minimum area, and Region maximum area parameters.
The available options and their corresponding units are the following:
- Square map units—The square of the linear units of the output spatial reference. This is the default.
- Square miles
- Square kilometers
- Hectares
- Acres
- Square meters
- Square yards
- Square feet
Number of regions specifies the number of regions the Total area value will be distributed across.
The maximum number of regions that can be specified is 30. The default is 1.
Evaluation criteria
The Evaluation criteria group includes the following parameters:
Shape/Utility tradeoff (%) specifies the weight for the cells when growing the candidate regions in the parameterized region-growing algorithm. The weighting is a trade-off between a cell's contribution for maintaining the region shape relative to the utility contribution of the cell's attribute value.
Higher values indicate maintaining the shape of the region is more important than selecting higher utility values. The acceptable percent values are 0 to 100, inclusively. The default is 50.
This parameter is used to identify the feasible candidate regions. The candidate regions that will be selected by the algorithm are controlled by the Evaluation method parameter.
Evaluation method specifies the evaluation criteria to be used for determining which of the candidate regions identified in the parameterized region-growing algorithm are most preferred. The preference can be specified based on a particular statistic of the utility values, or spatial arrangement of the cells within the regions.
The available options are the following:
Highest average value—Selects regions based on the highest average value. This is the default.
Highest sum—Selects regions based on the highest sum.
Highest median value—Selects regions based on the highest median value.
Highest value—Selects regions based on the highest individual cell value contained within the region. This option ensures that the best individual cells are selected.
Lowest value—Selects regions based on the lowest individual cell value contained within the region. This option ensures that the selected regions contain cells with low utility.
Greatest core area—Selects regions based on the greatest core area. Any cell that is farther than one cell from the edge of a region is considered to be part of the core. The edge distance can be controlled by the analysis cell size. Setting a smaller cell size can increase the core area.
Highest sum of core utility values—Selects regions based on the highest cumulative sum of the utility values for the core area. The edge distance can be controlled by the analysis cell size.
Greatest edge—Selects regions based on the greatest amount of edge using the P1 ratio, which is the ratio of the perimeter of the shape to the perimeter of a circle of the same area. The P1 ratio for a circle is 1.
Region requirements
The Region requirements group includes the following parameters:
Region shape specifies the shape characteristics for the output regions.
The regions start from seed cell locations and grow outward with preference given to the cells that maintain the specified shape.
The available shape options are Circle, Ellipse, Equilateral triangle, Square, Pentagon, Hexagon, and Octagon. The default is Circle. When a shape is specified, the cells that maintain the specified shape regions will receive a greater weight.
Region orientation specifies the orientation of the defined shape. Regions are grown from the seed locations with preference given to the cells that maintain the specified orientation of the region shapes.
The orientation values are in compass degrees ranging from 0 to 360, increasing clockwise starting from north. The default is 0.
The default of 0 orients the shapes in the following manner:
- Circle—No effect.
- Ellipse—The minor axis is orientated north-south.
- Triangle and Pentagon—One point is straight up.
- Square, Hexagon, and Octagon—One flat side is oriented east-west.
If Region shape is set to Circle, the Region orientation parameter is unavailable.
Region minimum area is the minimum area allowed for each region.
The units specified by the Area units parameter will be used.
Region maximum area is the minimum area allowed for each region.
The units specified by the Area units parameter will be used.
Minimum distance between regions is the minimum distance allowed between regions. No two regions can be within this distance.
This parameter influences the parameterized region-growing algorithm. If a cell has the potential of being added to a candidate region, but it is within this distance from any individual region in the dataset specified by the input raster or feature of existing regions parameter, it will not be considered for the candidate region. The minimum distance setting is not applied to excluded locations (NoData cells).
The units specified by the Distance units parameter will be used.
Maximum distance between regions is the maximum distance allowed between regions. No region can be farther apart than this distance from at least one other region.
When sequentially selecting regions, if the next best region is farther than this distance from any of the selected regions, it will not be considered at this time, but it may be selected later when more regions are selected.
The maximum distance is applied to the dataset specified in the input raster or feature of existing regions parameter, in that at least one of the selected regions must be within the maximum distance from existing regions. The maximum distance setting is not applied to excluded areas (NoData cells) and has no effect on the parameterized region-growing algorithm.
The units specified by the Distance units parameter will be used.
Distance units specifies the distance units that will be used for the Minimum distance between regions and Maximum distance between regions parameters.
The available options and their corresponding units are the following:
- Map units—For the linear units of the output spatial reference. This is the default.
- Miles
- Kilometers
- Meters
- Yards
- Feet
Region growth specifications
The Region growth specifications group includes the following parameters:
Number of neighbors to use in growth specifies the neighboring cells that will be considered in the growth of the regions.
The available options are the following:
- Four—Only the four direct (orthogonal) neighbors of the region cells will be considered in the region growth.
- Eight—The eight nearest neighbors (orthogonal and diagonal) will be considered in the region growth. This is the default.
Islands not allowed in regions specifies whether islands will be allowed within the potential regions.
Checked—The parameterized region-growing algorithm ensures that there will be no islands within a region. This is the default.
A flood field algorithm is implemented as a postprocess once the regions are created but before the regions are selected. If there are islands within a region, they will be filled and the cells will join the region. Since the fill process occurs before the selection process, the utility of the island cells will be added to the region, and their values will be included in the selection process of the regions and in the statistics of the output regions. As a result of the fill process, it is likely that the total area allocated will exceed the target specified by the Total area parameter.
Unchecked—Islands will be allowed.
Number of seeds to grow from specifies the number of seeds from which to grow the potential regions.
The available options are the following:
Based on input—The number of seeds will be based on the number of cells in the input raster. This is the default.
When the input raster has 100,000 cells or fewer, the tool uses the maximum number of seeds. When the input raster has more than 100,000 cells, it uses the small number of seeds.
- Small—The number of seeds will be equal to 10 percent of the number of cells in the input raster, after NoData cells are excluded, but not to exceed 1,600 seeds.
- Medium—The number of seeds will be equal to 20 percent of the number of cells in the input raster, after NoData cells are excluded, but not to exceed 2,500 seeds.
- Large—The number of seeds will be equal to 30 percent of the number of cells in the input raster, after NoData cells are excluded, but not to exceed 3,600 seeds.
- Maximum—The region growth will occur at each available cell within the input raster. Available cells are all cells that are not NoData and not identified as an existing region.
Resolution of the growth specifies the resolution at which region growth will occur.
The input raster will be resampled to the resolution determined by the number of cells identified by this parameter. Once the regions are selected from the resampled intermediate raster, the selected regions will be resampled to the analysis cell size, either specified from the Environment settings, or calculated internally by the tool, from the inputs provided.
An adjustment to the target resolutions identified below can be implemented if the number of cells in the specified average region size is too small or too large. This adjustment ensures that there will be enough cells in each specified region or that unnecessary processing will not occur. As a result, the total cells for the intermediate resampled raster for each of the specified resolutions below can be lower or higher than the target number of cells.
If the input has fewer than 147,356 cells or Maximum is specified, no resampling will occur and the region growth will process on all cells in the input raster. If the input raster has fewer than 147,356 cells, the Low, Medium, or High options have no effect.
The available options are the following:
Based on input—The resolution will be based on the number of cells in the input raster. This is the default.
When the input raster has 500,000 cells or fewer, the tool uses the maximum resolution. When the input raster has more than 500,000 cells, it uses the low resolution.
Low—The analysis will be performed on an intermediate raster containing 147,356 (384 x 384) cells distributed in the same x and y ratio as the input raster.
Medium—The analysis will be performed on an intermediate raster containing 262,144 (512 x 512) cells distributed in the same x and y ratio as the input raster.
High—The analysis will be performed on an intermediate raster containing 589,824 (768 x 768) cells distributed in the same x and y ratio as the input raster.
Maximum—The analysis will be performed on all cells in the input raster.
Region selection method specifies how the regions will be selected.
The available options are the following:
Based on number of regions—The selection method will be based on the Number of regions parameter. If the Number of regions value is eight or fewer, the Combinatorial selection method is used. If the Number of regions value is greater than eight, the Sequential selection method will be used. This is the default.
Combinatorial—Selects the best regions based on the specified evaluation method, while honoring the spatial constraints, by testing all combinations of the specified number of regions within the candidate regions from the parameterized region-growing algorithm.
Sequential—Sequentially selects the best regions based on the evaluation method and that meets the spatial constraints until the specified number of regions is reached.
Result layer
The Result layer group includes the following parameters:
- Output raster name is the name of the output raster layer that will be created and added to the map.
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.
- 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
- Processing extent
Note:
The default processing extent is Full extent. This default is different from Map Viewer Classic in which Use current map extent is enabled by default.
- Snap raster
- Cell size
- Mask
Output
The output is a regions raster. Each region is uniquely numbered with values greater than zero. Cells that do not belong to any regions will be assigned zero.
The output is always an integer raster.
Usage requirements
This tool requires the following user type and configurations:
- Creator, Professional, or Professional Plus user type
- Publisher or Administrator role, or an equivalent custom role
- ArcGIS Image Server configured for raster analysis
Resources
Use the following resources to learn more:
- How Locate Regions works
- Locate Regions in ArcGIS REST API
- Locate Regions in ArcGIS Pro with the Spatial Analyst extension