Data Design Attribute Type In ArcGIS Lec No. 8

Data Design: Attribute Type in ArcGIS

Attributes, which describe qualities associatedwith features, are stored in tables. Data attribute type and field properties, such as precision, scale, or length, must be specified when creating fields for the attribute table of a new shapefile or when adding a new field to the attribute table for an existing shapefile. The choice of attribute data type and associated settings affect storage and display and can have serious consequences for the accuracy and efficiency of the underlying database. In ArcGIS, you can store a value for a feature attribute as one of seven data types—short integer, long integer, float, double, text, date, and binary large object (BLOB). Attribute tables also contain predefined fields that hold data on geometry and the object ID. Float and double data types contain real numeric values and are used for continuous data that is measured or calculated. Short and long integer data types store data that represents numeric values that can be counted or that designate a coded value used for classification. Text data fields can also store coded values or contain descriptive text that characterizes a feature or provides its name. Temporal aspects of a feature, such as when a valve was last tested, are stored as a date type. BLOB data types allow integration of other media such as video, images, or sound.