B U S I N E S S   A N A L Y S T   10.2   R E S T   T R A D E   A R E A   T A S K

Remove Overlap Endpoint

Removes overlap (cannibalization) between trade areas.

Availability: Business Analyst Server.

http://localhost:6080/arcgis/rest/services/DefaultMap/MapServer/exts/BAServer/RemoveOverlap/execute

Specific Parameters

Other Parameters

Returns

Variable of type TaskResultOutput. If the input Boundaries layer has no overlapping areas, an error is returned.

Remarks

The Remove Overlap endpoint removes cannibalization between trade areas generated in Business Analyst Server or custom derived trade areas. Overlap is removed using Thiessen polygons or the grid-based approach to find the midline between the intersecting areas.

The CenterMethod parameter specifies a way to identify center points of trade areas of the Boundaries layer—using area centroid (default) or using the location of store the trade area is associated with. In the last case, the following parameters should be specified:

• the AreaLinkField parameter specifies a field in the Boundaries layer containing ID of associated store (this is usually the STORE_ID field),

• the Stores parameter specifies the store layer, and

• the StoreIDField parameter specifies a field in the Stores layer containing store ID.

The OverlapMethod parameter specifies a method for area overlap removing—using Thiessen polygons (default) or using grid.

The WeightMethod parameter specifies a weight method used by the grid overlap removing method. Default method is "use area".

NOTE 1: Since Business Analyst Server 10.0, the SummaryDataLayerID parameter is replaced with an optional DataHierarchy parameter.

NOTE 2: Since Business Analyst Server 10.0, the OutputReportItem parameter is replaced with the OutputReportItems parameter which is an array of folder items. The number of items in this array should be equal to the number of items in the ReportOptions array.

NOTE 3: Since Business Analyst Server 10.0 SP1, the AreaIDField parameter is replaced with AreaLinkField.

How Does it Work

Assume you have two intersecting trade area polygons.

In the example below, the highlighted light blue area represents the overlap area. The two triangle symbols represent the stores for each trade area.

The RemoveOverlap method in Business Analyst Server is based on the assumption that the overlap is only removed by dividing the intersecting area. The method does not assign areas that are not overlapped to other stores. In the example above, only the area that is shaded blue will be affected by the RemoveOverlap method.

There are two approaches for removing overlap:

Method 1—Thiessen Polygon

The Thiessen polygon approach removes overlap between two or more trade areas using straight lines to divide the area of overlap. This approach uses a series of geometric functions to create nonoverlapping trade areas. First, a line is drawn between each store and a neighboring store.

Second, a perpendicular line is drawn bisecting the line drawn between the stores at a right angle. The dotted line below is drawn at the midpoint between the two store locations and represents the division between the two trade areas.

Method 2—Grid

The grid approach takes into account weights of the stores and the shape of the overlapping polygon to make the division more natural.

The grid approach uses a series of geometric functions to create nonoverlapping trade areas. First, a line is drawn between each store and a neighboring store. Second, two parallel lines are drawn that pass through the stores perpendicular to the line drawn between the stores. The red shaded area below illustrates the target area of intersection. This area is determined by finding the area of overlap between the two trade areas contained between the two perpendicular lines.

After determining the area of intersection, a grid is created by drawing parallel lines between the two stores. A simplified example is illustrated below.

Intersection points are then determined within the red area so each grid line can be divided into nonoverlapping trade areas. The yellow points above illustrate how the midpoints are determined. These points are connected to represent the division between the overlapping trade areas.

In the grid approach, there are three different methods for determining where to draw the intersection line. These three methods determine how the midpoints are set to draw a line between the two polygons to remove the overlap. Specifically, these three methods determine where the yellow dots are placed.

Use weight field

The weight method uses a numeric weight field you specify to determine the location of the midpoints. For example, you could use the ratio of the size of each store (gross leasable area or square footage) to determine where to draw the area of overlap. If the green store is larger than the red store, the yellow dots will move to the right and the resulting green trade area will be larger.

Use area of trade area as weights

If you do not have numeric attribute data to determine the weights, you can use the area of the trade areas to determine the location of the midpoints. This method assumes that larger trade areas will have more influence in a particular market. For example, the green store's trade area is larger, and the yellow dots will move to the right.

Use the actual midpoint of the intersecting grid line

In this method, the midpoints are placed so the grid lines are divided equally in the red shaded area. The geometric midpoint is determined by measuring the length of each parallel grid line and dividing each line equally between the stores.

Usage Tips

• The spatial reference of the output feature layer will be the same as the trade area layer.

• The trade area layer must be a polygon feature layer.

• In most cases, the trade area layer will be a trade area created in Business Analyst Server.

• The Thiessen polygon method will remove overlap using straight lines.

• The grid approach will remove overlap with a line that reflects the shape and curve of the input polygon feature layer.

Example Usage

The example below generates non-overlapping trade areas derived from two overlapping trade areas.

http://localhost:6080/arcgis/rest/services/DefaultMap/MapServer/exts/BAServer/RemoveOverlap/execute?
Boundaries={"RecordSet":{
  "geometryType":"esriGeometryPolygon",
  "spatialReference":{"wkid":4326},
  "features":[
    {
      "geometry":{
        "rings":[[
          [-117.07193,32.772579],
          [-117.23774,32.746418],
          [-117.232982,32.870448],
          [-117.07193,32.772579]
        ]],
        "spatialReference":{"wkid":4326}
      },
      "attributes":{
        "AREA_ID":"1_1",
        "STORE_ID":"1",
        "RING":1,
      }
    },
    {
      "geometry":{
        "rings":[[
          [-117.43154,32.91412],
          [-117.14076,32.91412],
          [-117.14076,32.81997],
          [-117.43154,32.81997],
          [-117.43154,32.91412]
        ]],
        "spatialReference":{"wkid":4326}
      },
      "attributes":{
        "AREA_ID":"2_1",
        "STORE_ID":"2",
        "RING":1,
      }
    }
  ]
}}&OutputType=GetFeatureClass&
f=PJSON

{
  "results":
  [
    {
      "paramName":"OutputFeatureClass",
      "dataType":"GPFeatureRecordSetLayer",
      "value":
      {
        "geometryType":"esriGeometryPolygon",
        "spatialReference":
        {
          "wkid":4326
        },
        "fieldAliases":
        {
          "OBJECTID":"Object ID",
          "AREA_ID":"AREA_ID",
          "RING":"RING",
          "STORE_ID":"STORE_ID"
        },
        "fields":
        [
          {
            "name":"OBJECTID",
            "type":"esriFieldTypeOID",
            "alias":"Object ID"
          },
          ...
          {
            "name":"STORE_ID",
            "type":"esriFieldTypeString",
            "alias":"STORE_ID",
            "length":256
          }
        ],
        "features":
        [
          {
            "geometry":
            {
              "rings":
              [
                [
                  [
                    -117.233003,
                    32.747165
                  ],
                  ...
                  [
                    -117.233003,
                    32.747165
                  ]
                ]
              ],
              "spatialReference":
              {
                "wkid":4326
              }
            },
            "attributes":
            {
              "OBJECTID":1,
              "AREA_ID":"1_1",
              "RING":1,
              "STORE_ID":"1"
            }
          },
          {
            "geometry":
            {
              "rings":
              [
                [
                  [
                    -117.14076,
                    32.863424
                  ],
                  ...
                  [
                    -117.14076,
                    32.863424
                  ]
                ]
              ],
              "spatialReference":
              {
                "wkid":4326
              }
            },
            "attributes":
            {
              "OBJECTID":2,
              "AREA_ID":"2_1",
              "RING":1,
              "STORE_ID":"2"
            }
          }
        ]
      }
    }
  ],
  "messages":
  [
  ]
}

NOTE: The response has been abbreviated where "..." is noted.

JSON Response Example Rendered with the ArcGIS API for JavaScript

See Also

• Business Analyst Server REST Reference