Now you have joined owner
data to the Parcels layer and saved the result to a new data store.
You can use the combined information to create a calculated property.
The calculated property is the result of an expression: in this case,
the last sales price divided by the area.
create or manage calculations, you must be connected to the data store
that contains the data for the calculation.
To create a calculated property using
- If the Data Table is
not still open from the previous exercise, select the Parcels layer
in Display Manager and click Table.
- At the bottom of the Data
Table, click Options Create
- In the Create A Calculation dialog
box, name the calculated property “ValueByArea.”
- Click Properties.
Select Assessor| LAST SALES PRICE.
All properties for
this feature class are listed in the Property list.
- Click the operator for “divided by” (the
- Click Geometric Area2D.
This option calculates
the area of a polygon.
- Hold your cursor inside the parentheses,
where you see the text “geometry property.” On the tooltip that
displays, click Enter A Property.
- 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.
- Click Validate to
make sure that the expression is a valid calculation.
- 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.
- 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.