Summary
Creates a table with statistics based on polygon contiguity (overlaps, coincident edges, or nodes).
Illustration
Usage
The tool analyzes polygon contiguity, summarizing the
- Area of overlaps (overlapping neighbors—optional)
- The length of coincident edges (edge neighbors)
- The number of times boundaries cross or touch at a point (node neighbors)
Only first-order contiguity is analyzed and reported by the tool; relationships beyond that are not examined; that is, neighbors of neighbors (second-order contiguity) are not examined.
The Report By Field(s) parameter (in_fields in Python) is used to identify unique polygons or polygon groups and report their neighboring information by the polygons or polygon groups. To find the neighbors of each individual polygon in the input, specify one or more input fields that result in a unique value or set of values (in the case of using multiple fields) for every polygon.
If the specified fields identify unique polygon groups, the neighboring information is summarized and reported by the groups.
See How Polygon Neighbors works for details on the use of this parameter.
Include area overlap can be used if you want area overlapping relationships to be analyzed. When Include area overlap is selected, the output table contains a field called AREA that holds the area of overlap for the overlapping neighbor being analyzed. If no overlap is found, AREA is 0.
There is no entry in the output table for features that are not neighbors.
The Include both sides of neighbor relationship check box on the tool dialog box is used to control the relationships included in the output. To report all contiguity relationships, including reciprocal relationships, check Include both sides of neighbor relationship (both_sides = "BOTH_SIDES" in Python). For example, if OID1 is a neighbor of OID2, an entry is written to the output table for OID1 having a neighbor OID2 and for OID2 having a neighbor OID1. If you only want the first side of the relationship, uncheck Include both sides of neighbor relationship. Using the example above, but with Include both sides of neighbor relationship unchecked, only the entry for OID1 having a neighbor OID2 is entered into the output table.
Output Linear Units specifies the units to use for shared boundary length between neighbors. The default is to use the same units as defined by the input feature coordinate system.
Output Area Units is only used when the Area Overlap parameter is checked (area_overlap = "AREA_OVERLAP" in Python). When Area Overlap is checked, the units used to calculate the area overlap of neighbors are specified in the Output Area Units parameter. The default is to use the same units as defined by the input feature's coordinate system.
The Output Table can be a file geodatabase table, personal geodatabase table, or .dbf table.
The output table contains the following fields:
- src_field(s)—The prefix, src, stands for source; and field is a field specified in the Report By Field(s) parameter. You get as many such fields as you specify in the Report By Field(s) parameter.
- nbr_field(s)—The prefix, nbr, stands for neighbor; and field is a field specified in the Report By Field(s) parameter. Similar to the src_field(s), you get as many such fields as you specify in the Report By Field(s) parameter.
- AREA—This field stores the total overlapping area between a source polygon and a neighbor polygon (overlapping neighbors). This field is included in the output table only when the Include area overlap parameter is checked (area_overlap = "AREA_OVERLAP" in Python ).
- LENGTH—This field stores the total length of coincident edges between a source polygon and a neighbor polygon.
- NODE_COUNT—This field stores the number of times a source polygon and a neighbor polygon cross or touch at a point.
If there is a selection set on the input features, only selected features are analyzed.
Syntax
PolygonNeighbors_analysis (in_features, out_table, {in_fields}, {area_overlap}, {both_sides}, {cluster_tolerance}, {out_linear_units}, {out_area_units})| Parameter | Explanation | Data Type |
in_features | The input polygon features. | Feature Layer |
out_table | The output table. | Table |
in_fields [field,...] (Optional) | Input attribute field or fields used to identify unique polygons or polygon groups and represent them in the output. | Field |
area_overlap (Optional) | Determines if overlapping polygons will be analyzed and reported in the output.
| Boolean |
both_sides (Optional) | Determines if both sides of neighbor relationships will be included in the output.
| Boolean |
cluster_tolerance (Optional) | The minimum distance between coordinates before they are considered equal. By default, this is the XY Tolerance of the input features. | Linear unit |
out_linear_units (Optional) | Units used to report the total length of the coincident edge between neighboring polygons. The default is the input feature units.
| String |
out_area_units (Optional) | Units used to report the area overlap of neighboring polygons. The default is the input feature units. This parameter is only enabled when area_overlap = "AREA_OVERLAP".
| String |
Code Sample
PolygonNeighbors example (Python window)
Find each electoral districts neighbors in the province of Nova Scotia.
import arcpy
arcpy.env.overwriteOutput = True
arcpy.MakeFeatureLayer_management(r"C:\Data\Canada\CanadaElecDist.shp",r"Canada_ElectoralDist")
arcpy.SelectLayerByAttribute_management(r"Canada_ElectoralDist", "NEW_SELECTION", "\"PROVCODE\" = 'NS'")
print("Selected feature count: " + str(arcpy.GetCount_management(r"Canada_ElectoralDist")))
arcpy.PolygonNeighbors_analysis(r"Canada_ElectoralDist", "ENNAME", r"C:\Data\Output\NS_elec_neigh.dbf")
print(arcpy.GetMessages())
Environments
Licensing Information
- ArcGIS for Desktop Basic: Yes
- ArcGIS for Desktop Standard: Yes
- ArcGIS for Desktop Advanced: Yes