Analyzing a Single Layer That Fills a Large Portion of the Extent

Assume that you have a layer that contains the block groups for the US Census Bureau for the entire United States. This information is stored in a table called US, in a column called GEOMETRY. The extents of this layer (in the USER_SDO_GEOM_METADATA view) are -90 to 90 and -180 to 180.

You start the Spatial Index Advisor. In the Add Layer dialog box, you select the layer US(GEOMETRY). The alias is set to US and the color is set to black. After you click OK, the application does the following:

Labels the axes with the full extent of the US layer.
Makes US the current layer (in the choice box)
Displays information in the Tips area

You decide to examine these geometries in detail, so you click the Zoom to Reasonable Size toolbar button (or select View > Zoom to > Reasonable Size). You move the pointer to the center of where you think the U.S. area is and click. However, you see a warning that no geometries were found in the current viewport, so you pan to find the correct location of the U.S. and click again.

You view the information and recommendations in the Tips area, display fixed-size and variable-size tiles, and query some desired geometries (Layer > Query > ...). Based on the information displayed, you decide whether or not to modify the index.

See also: Usage scenarios, Main help topics (outline)