Exercise 4: Use the joined data for calculated fields and styles

Now that you have joined owner data to the parcels layer, you can use the joined information to create a calculated field and determine your styles.

Note:

This exercise uses the AnalyzeMap1.dwg map you created and modified in the previous exercises.

To create a calculated field using joined data

1. At the bottom of the Data Table, click OptionsCreate A Calculation.
2. In the Create A Calculation window, enter a name for the calculated field, for example “AcresByArea.”
3. Click Property to see a list of properties for the current layer. Select ACRES.
4. Click the operator for “divided by” (the slash character).
5. Hover over the [value] marker that is inserted to see a tooltip with choices. Click Enter a Property. Select AREA.
6. Click Validate to make sure that the expression is a valid calculation.
7. When you see “The expression is valid,” click OK to create the calculated field.

   Scroll to the right in the Data Table to see the new field (just to the left of the joined fields). It is gray, to indicate that it is a calculated field and cannot be edited. However, you can use it for styling.

8. Close the Data Table.

You can display information differently at different zoom levels in AutoCAD Map 3D toolset. Create a style that displays owner names on the parcel layer at a high zoom level, but not at a lower one. (The parcel owner names come from the joined data source.)

To create a style using the joined data

1. In Display Manager, select the Parcels layer and click Style.
2. Click the button in the field under Feature Label.
3. Click Add Label.
4. For Text Content, select Assessor|OWNERLASTNAME.
5. Click Apply and then click Close.
6. In the Style Editor, click Add a Scale Range so that you have two scale ranges, both the same.
7. Set the bounds of the first scale range to 0 to 10000 and the second to 10000 to Infinity.
8. Select the second scale range (10000 to Infinity).
9. Click in the Feature Label field.
10. Click the red X (at the top of the dialog box) to delete the label.
11. Click Apply and then click Close.
12. Close the Style Editor.
13. Save your map file.

The new Parcels style displays the names of the owners when the view is zoomed to 10000 or closer. The labels are not displayed when you zoom out beyond that scale.

Where you are now

You joined information from a Microsoft Access database to a layer containing parcels. Using the combined data, you created a calculated field. You created a style that displays parcel owner information at high zoom levels, but does not display these labels at lower zoom levels.

To continue this tutorial, go to Lesson 3: Analyze Data by Proximity Using Buffers