Euclidean Allocation

Calculates, for each cell, the nearest source based on Euclidean distance.

Learn more about how Euclidean functions work


Usage Tips

Syntax

EucAllocation_sa (in_source_data, out_allocation_raster, maximum_distance, in_value_raster, cell_size, source_field, out_distance_raster, out_direction_raster)
Parameter Explanation Datatype
Input raster or feature source data (Required)

Input source locations.

A raster or feature dataset in which the zone of closest cells is determined for each defined location. The value of each location in the input source dataset is assigned to its respective zone in the output raster.

For rasters, the input can be integer or floating point. If the input is floating point, a value raster must be set. The value raster must be integer. The value raster will take precedence over the source field if it is set.

Composite Geodataset
Output allocation raster (Required)

A raster that identifies the zone that could be reached with the least accumulative cost from each source location.

Raster Dataset
Maximum distance (Optional)

Defines the threshold that the accumulative distance values cannot exceed.

The {maximum_distance} defines the extent for which the accumulative Euclidean distances are calculated. If an accumulative Euclidean distance value exceeds the {maximum_distance}, the output value for the cell location will be NoData. The default distance is to the edge of the output raster.

Double
Input value raster (Optional)

An optional integer input raster that identifies the zone values that should be used for each source location on the in_source_data.

For each source location (cell or feature), the value defined by the {in_value_raster} will be assigned to all cells allocated to the source location in the cost allocation computations. The value raster will take precedence over any setting for the {source_field}.

This parameter can be used if other values or zones are used instead of those existing in the input source. This parameter must be used if the source field is floating point. This parameter can also be used if the source raster was created by the Test function, a Boolean operator that will only output the binary values zero and one.

Composite Geodataset
Output cell size (Optional)

The cell size at which the output raster will be created.

This will be the value in the environment if it is explicitly set. If it's not set in the environment, and if the in_source_data is a raster, the cell size will default to that of the in_source_data. If the in_source_data is a feature dataset, the cell size will default to the shorter of the width or height of the extent of input features in the input spatial reference, divided by 250.

Analysis cell size
Source field (Optional)

The field used to assign values to the source locations when the {in_value_raster} is not set. The value raster will take precedence over any setting for the {source_field}.

If the {source_field} is floating point, an {in_value_raster} must be used. By setting the {in_value_raster}, the field set for the {source_field} parameter will be overridden by the value field of the {in_value_raster}.

Field
Output distance raster (Optional)

The name of the output Euclidean distance raster.

The distance raster identifies, for each cell, the Euclidean distance to the closest source cell, set of source cells, or source location.

Raster Dataset
Output direction raster (Optional)

The name of the output (Euclidean) direction raster.

The direction raster contains the calculated direction, in degrees, each cell center is from the closest source cell center. The range of values is 0 to 360 degrees, with 0 reserved for the source cells. Due east (right) is 90, and the values increase clockwise (180 is south, 270 is west, and 360 is north).

Raster Dataset
Data types for geoprocessing tool parameters

Script Example

# EucAllocation_sample.py
# Description: 
#   Calculates for each cell its nearest source based on 
#   Euclidean distance.
# Requirements: None
# Author: ESRI
# Date: Sept 6, 2005

# Import system modules
import arcgisscripting

# Create the Geoprocessor object
gp = arcgisscripting.create()

try:    
    # Set local variables
    InSourceData = "C:/data/source.shp"
    OutAllocRaster = "C:/data/alloc_ras"
    InMaxDistance = "2"
    InValueRaster = ""
    InCellSize = "30"
    InSourceField = "SOURCEID"
    OutDistanceRaster = "C:/data/dist_ras"
    OutDirectionRaster = "C:/data/dir_ras"

    # Check out Spatial Analyst extension license
    gp.CheckOutExtension("Spatial")

    # Process: EucAllocation
    gp.EucAllocation_sa(InSourceData, OutAllocRaster, InMaxDistance, InValueRaster, InCellSize, InSourceField, OutDistanceRaster, OutDirectionRaster)

except:
    # If an error occurred while running a tool, then print the messages.
    print gp.GetMessages()

Map Algebra syntax

See EucAllocation


ArcObjects syntax

See EucAllocation


See Also

  • EucAllocation
  • Euclidean Direction
  • Euclidean Distance
  • An overview of the Distance tools