锚edSnapper

可能有的功能候选人features snapped to them. Arcs are snapped as linear features, and ellipses are snapped as polygonal features.

Features that may be snapped to锚特征。弧作为线性特征扣为线性特征，省略号被捕获为多边形功能。

候选人s whose geometry is changed by the transformer.

候选人s that leave the transformer without being changed.

• If a line or area feature snaps down to a single location, it will be output as a观点geometry, through theCollapsed港口。
• If an总计的那多体子， 或者多阵风geometry has any parts snap down to a single location, a观点geometry for each part will be bundled up into aMultiPointgeometry and output through theCollapsed港口。未按向单个位置（如果有）的剩余部分将作为组输出Snapped港口。

The anchors that were used during snapping. If a candidate was snapped to a point along the segment of an anchor, a new node is inserted into the anchor’s geometry.

If you selectGroup By属性，只有那些具有相同的功能Group By属性值将被捕获在一起。

结束过程（阻塞）：这是默认行为。只有在存在所有输入时，处理将在此变换器中发生。

组更改时的过程（高级）：此变压器将按顺序处理输入组。通过输入流上参数的Group的值的更改将触发当前累积组的处理。这可以提高整体速度（特别是具有多个等大小的组），但如果输入组未真正有序，则可能导致不期望的行为。

Considerations for UsingGroup By

There are two typical reasons for using组更改时的过程（高级）。The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.

The second possible reason is potential performance gains.

Performance gains are most likely when the data is already sorted (or read using aSQL ORDER BYstatement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).

根据数据流的数量，排序变得更加困难。由于所有匹配的功能，多个数据流可能几乎不可能排序到正确的顺序中Group By需要在属于下一个组的任何功能（任何特征类型或数据集）之前到达。在这种情况下，使用Group Bywith结束过程（阻塞）may be the equivalent and simpler approach.

笔记：Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.

与许多情况一样，使用您的数据测试工作区中的不同方法是识别性能增益的唯一明确方式。

WhenSnapping Typeis终点捕捉：

• 变压器快照的端点特性,enter via the候选人通过通过该功能进入的功能的端口锚港口。锚功能不输出。
• 观点features can be used as锚或者候选人features, and候选人点也将被捕获（或线性基础特征）。
• 变压器不会改变区域特征。

WhenSnapping Typeis顶点捕捉：

• 变压器卡扣顶点features that enter via the候选人port to vertices of features that enter via the锚港口。锚功能不输出。
• 观点features can be used as锚或者候选人features, and候选人points will be snapped together (or to a linear锚功能）也是如此。
• The transformer will alter area features.

When this parameter is set toSegment Snapping：

• 变压器捕捉通过该曲线或点输入的顶点候选人port to lines of features that enter via the锚port, if their distances are within the specified tolerance.锚功能不输出。
• 变压器卡扣顶点候选人segments to锚分段如果它们的距离在沿着该段的任何点处的指定公差范围内。
• 候选人段的段锚segments will have new vertices introduced at the point of intersection, but the候选人segments will not be split.
• 段捕捉可能导致重复点，其中段已退化为一个点。
• Area features are altered by this operation as its vertices and segments are snapped.

Snapping Distancespecifies the distance, in ground units, that the snapping occurs between features.

WhenSnapping TypeisSegment Snapping，该变压器通过确保捕获输出中没有两个顶点在彼此的公差范围内，该变压器执行数据清洁，该数据清洁意味着在其他算法中使用它们在其他算法中使用的鲁棒性。

IfToleranceis set toAutomatic那a tolerance will automatically be calculated for the cleaning operation, based on the size of the inputs. Otherwise, a custom tolerance may be used.

此参数仅在要捕获功能的结束点时才适用。

• 绝不：当捕获时，线的端点将移动，并且不添加其他顶点。
• ALWAYS：线的原始终点（起始点）成为从末尾的第二个（开始），并添加新顶点以完成捕捉。
• forward_only：仅在执行此操作时添加一个新的顶点，该角度与原始线路段创建大于90度的角度。在这种情况下，如果添加顶点会导致少于90度角，则旧端点仍然移动。

使用文本编辑器

文本编辑器提供了一种方便的方法来构建来自各种数据源的文本字符串（包括正则表达式），例如属性，参数和常量，其中结果直接在参数内使用。

Text Editor

使用算术编辑器

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

条件值

根据通过或失败的一个或多个测试条件设置值。

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>）不应用作文字字符串值。

内容类型

字符串函数	这些功能操纵和格式化字符串。
特殊的角色	A set of control characters is available in the Text Editor.
Math Functions	Math functions are available in both editors.
日期/时间函数	Date and time functions are available in the Text Editor.
Math Operators	These operators are available in the Arithmetic Editor.
FME功能功能	这些主要是特定于特征的值。
FME参数	FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters	Create your own editable parameters.

笔记：并非所有变压器都提供所有工具。