Spatial Index

A spatial index is a special access method used to retrieve data from within the data-store. Spatial indexes allow users to treat data within a data-store as existing within a two dimensional context. A spatial index is a grid divided into a number of rectangles or cells. All cells have the same width and height. All cells, together, map a single large rectangle. Two fields are required from any record to map the record to the grid -- effectively the (X,Y) coordinate pair.

Spatial indexes are defined by the following properties:

Property

Description

Index Name

Name assigned to the index.

Resource ID

Unique id assigned to the index.

Index Rules

Determines what part of the data an index is to be created over.

Horz Min Value

Lowest horizontal value for the grid.

Cell Width

Width of an individual cell within the grid.

Horz Cell Count

Number of cells in one row of the grid.

Vert Min Value

Lowest vertical value for the grid.

Cell Height

Height of an individual cell within the grid.

Vert Cell Count

Number of cells in one column of the grid.

Boundary Flag

Defines how values that fall outside of the base values are handled.

Weight

Applied to results returned using this index.