Autodesk 15606-011408-9005 Tutorial - Page 309

7 Hold your cursor inside the parentheses, where you see the text "geometry property." On the tooltip that displays, click Enter A Property. 8 From the Properties list, select Geom (at the bottom of the list). Every spatial feature has a geometry property that you can use to calculate area or length. 9 Click Validate to make sure that the expression is a valid calculation. 10 When you see "The expression is valid," click OK to create the calculated property and return to the Data Table. Scroll to the right in the Data Table to see the new field. It is gray, to indicate that it is a calculated property and cannot be edited. 11 Close the Data Table. Where you are now You joined information from a Microsoft Access database to a layer containing parcels. You saved the layer out to a new SDF file, making all its data available in the future. You used the new data source to create a calculated property. To continue this tutorial, go to Lesson 4: Theme Polygon Features (page 301). Lesson 4: Theme Polygon Features You can use the new calculated property you created as the basis for a theme that styles parcels according to their value by area. Exercise 1: Create a theme A theme varies the display of individual features based on data values. For example, if you theme by parcel value, less expensive parcels can be a lighter color while more expensive ones are a darker shade. In this exercise, you create a theme based on the calculated property you defined for ValueByArea. NOTE This exercise uses the map you modified in Lesson 3: Use Joined Data to Create Calculated Properties (page 292). Lesson 4: Theme Polygon Features | 301