(zz)nnotation学习笔记2：关于Annotation与符号，还是要读arcmap帮助！！！

nnotation学习笔记2：关于Annotation与符号

2011年01月22日 星期六 15:07

2011-01-22，星期六，中国广州天河，天气继续冷，鼓起勇气，击退严寒！

继续一些Annotation的基本知识，这里的内容在arcGis Desktop help 中的 Annotation in the geodatabase 一节中。

An annotation feature class contains a collection of one or more text symbols that you define. Every time you create a new annotation feature, you assign it one of these predefined symbols. The symbol contains properties that describe how the annotation feature is drawn, such as font, size, and color. For example, if you have annotation for small, medium, and large cities, create threetext symbols of varying font sizes to assign to the annotation. Because each annotation feature needn't store its own symbol properties, ArcGIS is able to reduce storage requirements(减少储存要求，即不需要那么多空间) and maximize display and query performance. Committing to(原意为承诺，即预定义) a limited list of symbols can help you promote standards for any new annotation features you create.

Whenever you create an annotation class, you create a default text symbol for it. You can also create additional text symbols for a feature class at any time with the Feature Class Properties dialog box（在这里添加新的符号集）. Once you've created the symbols,assign them to annotation features when editing in ArcMap.（点明了在那里将样式库关联到Annotation featureclass 中）

根据上图，可以通过Create Feature Class 对话框创建标注，如果需要创建 feature-linked 类型的 标注，可以选择对应的Feature class

在创建的过程中可以添加自己定义的字段。

创建完成后，可以自己管理标注的样式集，如上图，我就在上面添加了一个新的样式集，如果这个Annotation FeatureClass 添加到arcMap中，则会显示为下图所示：

它的相关属性显示如下图，这对在arcEngine编程中理解 Annotation FeatureClass 十分有用。

对于每一个Annotaton featureclass 可在将预定义的样式应用于其身上，不过要先处于Editing状态，如下图所示：

可以对每一个Annotation feature 进行单独样式设置，如下所述：

 When assigning symbols to annotation features in ArcMap, you may discover that the text symbols you created do not contain the properties you need for one or more annotation features. For example, you may require a smaller font size to fit annotation into a congested area. One approach is to create a new text symbol with the new properties in ArcCatalog, then assign the new text symbol to the annotation features in an ArcMap edit session. Creating a new symbol for every unique set of properties you require could result in a long list of symbols that is difficult to work with. ArcMap allows you tomodify symbol properties on a feature-by-feature basis. When editing in ArcMap, you can select annotation and change any symbol property for that annotation. Editing certain symbol properties on a feature-by-feature basis causes annotation to lose its reference to its associated text symbol in the collection. When this happens, the annotation feature stores all its symbol properties. This increases the storage requirement and reduces display and query performance for the annotation.