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Display 'linked' attribute (with a legend)

The main purpose of this option is to enable display of one-to-many related attributes. Such attributes can be linked to a theme attribute table, but the theme legend cannot display symbols/colours based on an attribute in a linked table. One-to-one related attributes can be joined to the active theme and displayed directly, but one-to-many related attributes must be reduced to a one-to-one relation first. The process of displaying an attribute in an associated table therefore involves the following steps:

1. Choose the table with the ('linked') attribute to display

2. Query the table to enable one-to-one join of selected records

3. Export the selected records to a temporary table

4. Join the temporary table to the attribute table of the active theme

5. Select the attribute to display

6. Display the theme with a legend based on the 'linked' attribute

These steps are described in more detail in the following:

Choose the table with the ('linked') attribute to display

The first step creates a list of table documents that are not feature attribute table of themes. Then the user is prompted to select the table comprising the attribute he wants to display.

Query the table to enable one-to-one join of selected records

This step opens the Query window and enables the user to specify a query reduce a one-to-many related table to a one-to-one relation on selected records. E.g. if a table comprises 12 monthly values for each location, a query selection one particular month will enable display of this monthly value at each location.

Export the selected records to a temporary table

The user is first prompted for a temporary table to create. Existing tables can be overwritten if they are not active. Then the selected records are exported to this temporary table.

Join the temporary table to the attribute table of the active theme

The user is prompted to select the attribute in the temporary (associated) table and the attribute table of the active theme that are common and therefore enables a join of the two tables.

Select the attribute to display

The user is prompted to select the associated ('linked') attribute to display.

Display the theme with a legend based on the 'linked' attribute

Now that the attribute is joined to the theme attribute table, the legend can be displayed based on the attribute values of the originally one-to-many related attribute. First a unique classification is attempted, but if there are too many unique attribute values, the user is prompted to select Quantile or Equal interval classification and number of intervals.