Working with Text: Part 2
I really enjoy the way a small sailboat has gives me a feeling of being directly connected to the water, the air and the craft itself. More than just floating or paddling through the water, a sailboat allows me to use natural forces against one another for my gain. I can float if I want to, but generally I want to be going places.
In ArcGIS text can just float on its own, or it can be driven by features. In the most general terms GIS annotation could include any map text, marginalia, and displayed attributes. More explicitly there are different forms of text in ArcGIS using different data constructs. Any ArcGIS feature can have feature labels that are generated from attributes. Unlike ArcGIS feature labels ArcGIS annotation features are features in their own right. One higher level of annotation is that geometric features can have annotation features that belong to them, this is called feature-linked annotation. Or, text can be displayed as simple graphic text, that is not a feature, and not linked to other features, this form is the most similar to CAD text.
In ArcMap any GIS feature can have a displayed feature label. This feature labels can be toggled on an off as a property of the ArcMap label. The label can have justification and font properties and its text value is derived from the attributes of the feature layer. Labels are regenerated from the feature's attributes and generally are placed by a labeling engine. The default labeling engine has some simple options to avoid overlapping labels and the alike. An example of a high-end professional labeling engine would be something like ArcGIS’s Maplex labeling extension that uses sophisticated rules-based label placement algorithms. ArcGIS feature labels can be converted into ArcGIS annotation feature classes.
Another form of text, ArcGIS geodatabase annotation feature classes, have their own geometry, attributes and set of justification methods. Unlike feature labels that are placed on-the-fly using an engine from other feature layers’ attributes. Annotation features are persisted and stored in a feature class, along with their position and other display properties. Annotation features can be independent or they can be linked to other feature layers. Feature-inked Annotation derives its text value from the attributes of the linked feature class (like the diameter of a pipe, or name of a street), but retains its own separate geometry and properties (for example: a specific rotation or position on a map.)
You can learn more about ArcGIS text from the ArcGIS online help.
ArcGIS feature labels cannot be exported using for example the Export to CAD tool, but the tool does export geodatabase annotation features, which I can generate from feature labels in ArcMap.
The ArcGIS CAD feature class that is generated in memory when a CAD file is used by ArcGIS, is yet another form of text. The CAD annotation feature class is implemented as a file-based
annotation. This type of annotation is more akin to the legacy ArcInfo Coverage Annotation feature classes. Suffice to say it is old-school and lacks many of the nifty functionality available with the invent of geodatabase annotation feature classes.
There is a tool to convert file-based annotation and CAD annotation feature classes to geodatabase style annotation. This tool is called the Import CAD Annotation tool…