Join Areas

Join Areas groups art objects based on a specified similar attribute value. An attribute field is defined and a new object is created for each unique value within that field. Options can be set to create Adobe Illustrator groups or compound paths, while either maintaining the outlines of the original features or dissolving sub-areas into the larger area.

Using Join Areas

To use Join Areas, click the Join > Join Areas button on the MAPublisher toolbar or from the menu Object > MAPublisher > Join Areas. The Join Areas dialogue box has two tabs: Join and Attributes.

Target Layer

Select the Target Layer on which Join Areas should be performed.

Destination

On the Join tab, specify whether the join results are on the target layer or Copy the results to a new layer. Specify a new layer name if the latter option is selected.

Join Type

On the Join tab, specify the Join Type to either Join all selected areas on target layer or Join areas by attribute. Specify an attribute that the join will be based on. It is noted in the Attributes section Operation column as Join on.

Join Method

On the Join tab, select the Join Method type to either Adobe Illustrator Group areas or Create compound areas. For the latter option, choose to Dissolve borders between adjacent sub-areas. Not checking this option will maintain the borders of individual areas. For example, when grouping the countries of the world by its Continent field attributes, the Continent field will result in five new objects, one for each continent. Dissolving borders between adjacent sub-areas will leave the continent outlines. Choosing not to dissolve, the outline of each country will remain. In both cases, there will be one object for each continent in the attribute table.

Attributes

Click the Attributes tab to manage which attributes and operations are used.

The Original Attributes are listed with their intended operation and associated options. Click the Edit Original Attribute Operation button to change the original attribute operation.

When areas are joined, attributes are combined based on an operation. Often, these combinations are straightforward. However, depending on attribute and operation, some results may require additional thought. For example, after joining the countries of the world based on a Continent field, the field containing country capitals will no longer be valid, as each continent does not have one capital. Thus, operations can be set to determine how each attribute field is handled. By default all attribute operations are Set to default if different, meaning that the attribute is cleared if there are more than two unique values present after the join.

Only certain operations are available for a specific attribute type. The following details the operation, which attribute types are affected, and its description.

 When adding Calculated Attributes, it is possible for certain outcomes to change the attribute type. For example, a Concatenate operation performed on an Integer attribute type will result in the creation of a String attribute type.

To add a Calculated Attribute, click the Add Operation button. The Add Attribute Operation dialogue box allows you to choose a source and new operation with associated options. Choose an Operation based on availability set by the attribute data type. Provide a Name, result type and provide settings for associated options.

Inclusion

There are two options to apply attribute operations to grouped components. Choose Apply to every grouped component option to apply all. Alternatively, choose Only apply to grouped components that satisfy to enable the expression builder to enter an expression that will only apply the attribute operations to values of the object where the expression condition is met. All other values that aren't satisfied will be cleared. For example, the expression "Continent = Africa" would only apply the operations to attributes of the object that has the attribute "Continent" and value of "Africa". All attributes for this art object will maintain its attributes.

Results

To tell if areas are joined after executing the Join Areas function, look for visual differences of the features on the map or look in the Adobe Illustrator Layers panel. Depending on the join method, compound areas or grouped areas, the Layers panel will display the results. In the example below, the original Lower 48 layer is shown and two join method possibilities. The Group areas method shows states grouped by the attribute Sub Region (W S Cen, Pacific, etc). The Create compound areas method shows states joined by compound path (and in this case, with the option Dissolve borders between adjacent sub-areas enabled).