# Temporal relationships in the GeoAnalytics Desktop toolbox

The  Join Features tool allows you to join features in one layer to features in another layer based on spatial, temporal, or attribute relationships, or a combination of those relationships. For example, if two features occur within one hour of each other, they will be joined.

Features in time-enabled layers can be represented in one of the following two ways:

• Instant—A single moment in time
• Interval—A start and end time are given

Temporal relationships are based on ISO19108 - Temporal Schema.

## Join and target layers

A temporal join matches features from the join layer to the target layer based on the features' placement or occurrence in time.

The following legend applies to all examples in this topic:

• Target feature time—Green
• Join feature time—Blue

### Time types and supported relationships

The following table lists the supported temporal relationships for a temporal join between time types (for example, joining time intervals to time instants):

Temporal join (target feature to join feature) betweenInstant and instantInstant and intervalInterval and instantInterval and interval

Equals

During

Contains

Finishes

Finished by

Meets

Met by

Overlaps

Overlapped By

Starts

Started by

Intersects

Near

Near before

Near after

#### Equals

Two times are considered equal if their instant or interval are identical. The times must be of the same type to be considered equal—both instant or both interval times.

#### During

When a target time occurs between the start and end of the join time interval, the target time is during the join time. This is the opposite of the Contains temporal relationship operator. This relationship only occurs when the join feature has an interval time.

#### Contains

When a join feature time occurs between the start and end of the target time interval, the target time contains the join time. This is the opposite of the During temporal relationship operator. This relationship only occurs when the target feature has an interval time.

#### Finishes

When a target time ends at the same time as a join time, and the target time started after the join time, the target time finishes the join time. This is the complement of the Finished by temporal relationship operator and the opposite of the Starts temporal relationship operator. This relationship only occurs when the join feature has an interval time.

#### Finished by

When a join feature time ends at the same time as a target time, and the join time started after the target time, the target time is finished by the join time. This is the complement of the Finishestemporal relationship operator and the opposite of the Started by temporal relationship operator. This relationship only occurs when the target feature has an interval time.

#### Meets

When a target time interval end is equal to the join time interval start, the target time meets the join time. This is the complement of the Met by temporal relationship operator. This relationship only occurs when the join and target times are intervals.

#### Met by

When a target time interval start is equal to the join time interval end, the target time is met by the join time. This is the complement of the Meets temporal relationship operator. This relationship only occurs when the join and target times are intervals.

#### Overlaps

When a target time interval starts and ends before the start and end of the join time interval, the target time overlaps the join time. This is the complement of the Overlapped by temporal relationship operator. This relationship only occurs when the join and target times are intervals.

#### Overlapped by

When a target time interval starts and ends after the start and end time of the join time interval, the target time is overlapped by the join time. This is the complement of the Overlaps temporal relationship. This relationship only occurs when the join and target times are intervals.

#### Starts

When a target time starts at the same time as the join time interval start and ends before the join time interval ends, the target time starts the join time. This is the complement of the Started by temporal relationship operator and the opposite of the Finishes temporal relationship operator. This relationship only occurs when the join time is an interval.

#### Started by

When a target interval time starts at the same time as the join time and ends after the join time, the target time is started by the join time. This is the complement of the Starts temporal relationship operator and the opposite of the Finished by temporal relationship operator. This relationship only occurs when the target time is an interval.

#### Intersects

When any part of a target time occurs at the same time as the join time, the target time intersects the join time. The Intersects operator is a combination of all the other types of temporal relationships.

#### Near

When a target time is within a specified range of time from the join time, the target time is near the join time. Using a user-specified temporal distance (for example, 1 month), an Intersects relationship operator is applied with the temporal distance added to both ends of the join time.

#### Near before

When a target time is within a specified range of time and occurs before the join time, the target time is near before the join time. Using a user-specified temporal distance (for example, 1 month), an Intersects relationship operator is applied with the temporal distance added to the beginning of the join time.

#### Near after

When a target time is within a specified range of time and occurs after the join time, the target time is near after the join time. Using a user-specified temporal distance (for example, 1 month), an Intersects relationship operator is applied with the temporal distance added to the end of the join time.

##### In this topic
1. Join and target layers