Most maps need to convey a lot of information graphically. Even though many concepts such as location, shape, proximity and size are conveyed without text, a thematic or reference map often has hundreds or thousands of objects that need to be identified. One major goal of the cartographer is to accurately label all of these objects, while minimizing confusion and ambiguity through careful and consistent positioning, orientation and formatting of text.
AutoCAD Map 3D has a powerful automatic annotation tool, which allows you to easily generate labels for objects using tabular data, block attributes and AutoCAD object properties, such as length, elevation and area. A bit of setup is required to define a template, but the process is then automated, placing the formatted text on or near objects uniformly. This works well on a simple, uncluttered map, but legibility problems such as crowding and overlapping often occur with busier maps.
Once the annotation has been generated, you will likely need to adjust the positioning of some labels to fix these problems. One drawback to the AutoCAD MAP 3D Annotation feature is that the automatically generated labels are not dynamic. That is, changes to an object’s geometry are not automatically updated in the labels generated from it. For instance, a line’s length property may be used to generate a label indicating the object’s length, but if the AutoCAD line length is changed, the label will not automatically change with it. Similarly, if a label is generated from data in a table linked to an object, changes to the tabular data will not automatically change the associated label.
The annotation menu has an Update command, which will automatically update the labels. Unfortunately, if you have used the AutoCAD Move command to change the location of a label, the text will return to its default location any time an update is performed. Updates are required whenever you make changes to the annotation template, as well as any time a change is made to the property or data that needs to be reflected in the value of the label.
Therefore, any time you have used the AutoCAD Move command to change a label’s position, you will need to also use the Map > Annotation > Define Text Location command to ensure that it stays there after an annotation update. Once you have invoked the command through the menu (or a shortcut, if you plan to use it a lot), pick the object the label is associated with. A rubber band appears between the cursor and the default label insertion point. Now pick the insertion point of the moved label block, to establish the new position, which is now attached to the object.
The annotation feature is one of many tools you will learn in our books “Digging Into Autodesk Map 3D”. We offer editions compatible with versions back to 2004.