You can link data to objects as you digitize. Although you can store data in AutoCAD Map 3D as block attributes, you can perform more sophisticated analysis of the data if you use one of the following methods:
Each object that represents a different type of map data should go on a separate layer. For example, a polyline representing a coastline could go on a layer named COASTLINE, interstate highways on a layer named INTERSTATE, land boundaries on a layer named LOTS.
If you have not established a scheme for layer names, you can create one using the numeric feature-classification code found in some digital source data. For example, major roads might be on a layer named "170-201". A better naming convention combines names that suggest their function and a structure that allows selection with wild cards and groups of layer names. For example, you might decide that all topographic objects should go on layers beginning with the letters TP. So you might put rivers on a layer named TP_RIVERS, and contours on a layer named TP_CONTOURS. To freeze, thaw, lock, or unlock all layers with topographic data, you use the expression TP*. For more information on wild-card characters, look up "wild-card characters" in the help index.
Wherever possible, use the linetypes supplied with AutoCAD Map 3D to indicate different types of boundaries, road types, and waterways. Using standard linetypes ensures consistency across maps and helps you keep track of what you have digitized. Associate each linetype with a different layer.