Geographic Facets

You can create facets based on geographic points (both GPS and XY types). Like other facets, they automatically display a count of matching documents for each facet value.

You can also aggregate document values that fall within one or several geographic areas.

You can define the following types of geographic facets:

  • To return matches within a specified disk or polygon, create a Geographic facet. Use this facet when you know where to focus your search. You can define multiple disks or polygons for a facet. Each disk or polygon represents a facet value.

  • To highlight areas containing matches within a bounding box, create an Auto-tile geographic facet. Use this facet when you want to locate areas containing matches (known as tiles) within a larger area.

    By default, this bounding box (or the extent) is the entire globe, but you can modify this. Each tile represents a facet value.

This task shows you how to:

See Also
About facets
Configuring Geographic Search

Create Facets Based on Disks or Polygons

  1. In the Administration Console, go to Search > Search Logics > Facets.
  2. Click Add facet, specify a name, and select the Geographic type.
  3. In Index field, select a geographic field from the list.
  4. In Domains, for Type select the shape of the area, that is to say Disk or Polygon and specify the area’s extent.

    The coordinates depend on whether the facet is based on a GPS or XY point index field:

    • For a disk: specify a center point and a radius.
    • For a polygon: specify a list of coordinates, separated by semicolumns. Two successive points must be connected by an edge, and the polygon is automatically closed (an edge is added between the last and first point).

    Important: The time required for facet synthesis is directly proportional to the number of points in the polygon.

  5. (Optional) Add another disk or polygon area. You can mix polygons and disks within the same facet, and the areas can overlap.
  6. (Optional) Expand Aggregation to create a summary on an index field for this facet.
  7. Click Apply.

For an example (created in the XML configuration file, rather than in the Administration Console), see below.

Example

This example uses an ExplicitGeoFacet with one DiskDomain (blue) and two PolygonDomains (red and green), as shown in the figure below. 

<PolygonDomain title="redpoly" vertices="346,401;94,230;156,319;293,296;390,160;204,37"/>
<PolygonDomain title="greenpoly" vertices="689,377;542,397;539,526;685,464"/>
<DiskDomain title="bluedisk" x="501" y="641" radius="78"/>
Example of an ExplicitGeoFacet with One DiskDomain (Blue) and Two PolygonDomains (Red and Green).

In this example, dark red crosses represent indexed points for each document. The red and blue domains overlap, which is allowed, and the point that falls within the intersection counts once for each domain.

Five points fall into the red polygon domain, three into the disk, and one into the green polygon domain. Three points fall outside all domains, and so are not counted in the results.

Create Facets Based on a Bounding Box

  1. In the Administration Console, go to Search > Search Logics > Facets,
  2. Click Add facet, specify a name, and select an Auto-tile geographic type.
  3. In Index field, select a geographic field from the list.
  4. By default, the bounding box is the entire globe. If you want to change this, the coordinates depend on whether the facet is based on a GPS or XY point index field:
    1. Bounding box min: define the lower left limit.
    2. Bounding box max: define the upper right limit.
    3. Tile size: specify the size of the area to highlight when there is a matching point on the map.
  5. (Optional) Expand Aggregation to create a summary on an index field for this facet.
  6. Click Apply.

Display Geographic Facets in a Map Widget

  1. In Mashup Builder, drag a Google Maps widget onto your page.
  2. Select a feed for your widget.
  3. In the widget properties, go to the Based on Geo Facets tab.
    1. In Geo facets list, click inside the field, then select your geographic facets from the panel on the left.
    2. In Aggregation, click inside the field, then expand Aggregation from the panel on the left. From the list, select an aggregation. The higher this value, the darker the tile appears on the map.
  4. Click Apply.