Exercise 1: Define Split/Merge Rules

Lesson 2: Splitting a Polygon Feature

Lesson 2: Splitting a Polygon Feature

Exercise 2: Find the parcel to split

 

AutoCAD Map 3D Tutorials > Styling, Splitting, and Using Joined Data with Polygon Features > Lesson 2: Splitting a Polygon Feature > 

Exercise 1: Define Split/Merge Rules

You can use the AutoCAD Trim and Break commands to split polygons. However, the Split command has many advantages over those methods. A split always results in a valid feature, and has special logic to deal with attributes automatically.

With Split, you can set rules for the assignment of properties when you split and merge geospatial features. You can use expressions for these rules.

For example, if you are splitting a parcel, you can specify that the land value of the resulting parcels be based on a calculation that you define. There are also choices for automatic calculations, such as assigning the average value of all merged features to the resulting feature, or dividing the value of a feature evenly among all its split features.

To create split/merge rules

1. To display the Data Table, in Display Manager, select the Parcels layer and click Table in the Task Pane.
2. In the Data Table, click Options (at the bottom of the window) and select Set Split And Merge Rules.

   

   Each property of the Parcels feature is listed under Feature Properties on the left. Two properties (Geom and FeatID) are generated by the data store, so you cannot set rules for them. If you select them, you can see the rules that the data store uses to create them.

3. In the Split And Merge Rules dialog box, click the ADDRESS property.
4. For the Split Rule, specify Empty.

   If you split this parcel, you must specify the address number for each new parcel that is created.

5. For the Merge Rule, specify First Selected.

   If you merge multiple parcels into one, the new parcel will use the address number of the first parcel you select for the merge.

6. Specify rules for other properties, using the table below as a guide.

   Property	Split rule	Merge rule
   ACRES	Proportional Based On Area2D (Geom)	Sum
   APN	Copy	First Selected
   AREA	Proportional Based On Area2D (Geom)	Sum
   IMP_VALUE	Proportional Based On Area2D (Geom)	Sum
   LAND_VALUE	Proportional Based On Area2D (Geom)	Sum
   NET_VALUE	Proportional Based On Area2D (Geom)	Sum
   PRIMARY_INDEX	Empty	First Selected
   STNAME	Copy	First Selected

   For a complete description of the split/merge rule options, see Using Expressions In Split/Merge Rules.

7. Click OK.

To continue this tutorial, go to Exercise 2: Find the parcel to split.