Converting CAD text to geodatabase annotation
To convert CAD text to a geodatabase annotation feature class, you can choose from two geoprocessing tools:
- The CAD To Geodatabase tool converts a CAD dataset including its annotation. This tool requires minimal input and automatically creates an annotation subclass for each text layer in the CAD file. By default, the dialog box is populated with a reference scale of 1:1,000.
- The Import CAD Annotation tool converts individual CAD annotation feature classes. This tool provides options for creating annotation classes by layer, applying uniform font properties, referencing symbol collections, and linking the output feature class to the features in another feature class. By default, the dialog box is populated with a reference scale equal to the map scale displayed in the ArcMap toolbar. When a map scale is unavailable, the reference scale defaults to 1:1,000.
Unit of measure
A unit of measure is required for the annotation conversion tools to perform text and font size calculations. You provide the tools with a unit of measure by defining a coordinate system for the CAD dataset. If a coordinate system is not defined or set to unknown, the tools use meters as the default unit of measure.
The display size for the new annotation class will match the original CAD text when the units for the coordinate system match the units in the CAD file. When the units do not match, the tools may generate a font size that is unexpected. The tools do not issue a warning when they encounter mismatched units of measure.
A common example is when a CAD drawing is created in U.S. survey feet and not assigned a coordinate system. During conversion, the tools assume that 1 foot in the CAD file is 1 meter. As a result, the new annotation displays much larger than the original CAD text. When this occurs, resizing imported CAD annotation can be performed after conversion by opening the attribute table and changing the values in the FontSize field.
The CAD annotation conversion tools do not reference the units or coordinate system assigned to the data frame in ArcMap. After conversion, the display size of the new annotation class will reflect the units defined in the Data Frame Properties dialog box.
The reference scale is a relative scale at which the specified font size will display at true size (1:1). This can be useful for workflows that require the detail in the data frame to look the same on-screen in data view as it will in a published map at a specific scale. For example, when you are working on a map that will be printed at 1:25,000, by setting the reference scale to 1:25,000, the text sizes in your data frame will appear at the same size in relation to each other as they will in your printed map.
The reference scale is stored as a property of the annotation feature class. You can change the reference scale after conversion using the Feature Class Properties dialog box in the Annotation tab. Except for specific cartographic workflows, calculating a target reference scale is generally not required when importing CAD annotation.