Spatial Join

The Spatial Join tool joins attributes from features on one layer to features on another layer based on a spatial relationship. Spatial joins begin by selecting a target layer and comparing it spatially to another layer. Target features can inherit the attributes from the source features if and only if the two share the same spatial reference (MAP View).

Using Spatial Join

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

MAP View

On the Join tab, select the MAP View on which Spatial Join should be performed.

Add data to

On the Join tab, specify which MAP layer to add data to. Also known as the target features.

Join data from

On the Join tab, specify which MAP layer to join data from. Also known as the source features.

Relationship

On the Join tab, select the Relationship type to base the join on. Only supported relationships of the two feature types are shown in the Relationship drop-down.

 

Supported Spatial Relationships

 

Spatial Relationship	Description
Intersects	A intersects B if any part of A crosses with any part of B.
Near	A is near B if a line can be drawn from any part of A to any part of B that is less than the specified minimum distance.
Contains	A contains B if all of B is inside the boundary of A.
Within	A is within B if all of A is inside the boundary of B.
Identical To	A is identical to B if every vertex of A & B are exactly the same, in the same order.
Has Centre In	A has its centre in B if the centroid of A is ‘within’ B (see ‘Within’ above).
Closest	A is closest to B if a line can be drawn from any part of A to any part of B that is less than any other such line between B & any other feature.

 

Relationships Based on Feature Type

Precision

The Precision control specifies how many decimals to consider when comparing coordinates. If results are not as expected, adjust the slider to a lower or higher precision.

Attributes

Click the Attributes tab to manage which attributes and operations are used. Choose which source attributes to append or drop. By default, all attributes of the source features are appended to attributes of the target features. The New Attribute column shows which attribute will be appended based on the Derived From column. In addition, each attribute is appended based on an intended operation and associated options.

 

Click the Edit Calculated Attribute Operation button to change the attribute operation and options.

Often, these combinations are straightforward. However, depending on attribute and operation, some results may require additional thought. By default, operations are determined based on the attribute type, however, the operation can be adjusted as required.

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

 

Operation	Affects Attribute Type	Description
Set to default	All	The original attribute is retained after the join.
Set to default if different	All	The attribute is cleared if there are more than two unique values present after the join.
Concatenate	String	Joins string values together and separates them with a separator (tab, space, comma, comma then space, dash, underscore). No separator can also be used.
Sum	Integer, Double	The addition of two or more numbers.
Mean	Double	The average of a set of numbers.
Median	Integer, Double	The middle value in a range of numbers.
Mode	String, Integer, Double, Boolean	The value which appears most often in a range of numbers.
Range	Integer, Double	The difference between the lowest and highest values.
Standard Deviation	Double	A measure of how spread out numbers are.
Largest value	Integer, Double	The largest value in a range of numbers.
Smallest value	Integer, Double	The smallest value in a range of numbers.
Least alphabetical	String	Returns least alphabetical sort (Z-A).
Most alphabetical	String	Returns most alphabetical sort (A-Z).
First value	All	First value of an attribute.
Last value	All	Last value of an attribute.

 

 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.

Results

Examples of Spatial Join uses:

•Find all of the Cities contained by each province

•Make a list of the city names in each province

•Find the sum of their populations

•Find the mean of their populations