Attribute Query (Boolean Selection)

From Wiki.GIS.com

An attribute query is any SQL query used to select map features based on their attribute values. Attribute queries use Boolean algebra (and, or, not), set algebra (>, <, =, >=, <=), arithmetic operators (=, -, *, /), and user-defined values. Such queries are fundamental and an important first step in defining, working with, and analyzing GIS data. An alternative to using attribute query is to perform a spatial selection.

[edit] Select by Attributes in ArcGIS

In ArcGIS, the 'Select by Attributes' window provides a quick way to build a SQL query to create a selection based on map attributes. In the screenshot below, a simple SQL query has been built that queries the underlying 'POP' (population) attribute record of a layer containing information about US cities (citiesx020 in the example). After executing the query, only those cities having a population greater than 100000 will be selected in the map.

[edit] See also

• SQL
• Relational database management system
• GIS
• Boolean expression
• Spatial selection