Temporal data symbology
Temporal data is unique because it changes through time. The Tracking Analyst extension provides you with a variety of symbology options unique to tracking layers. It allows you to create time windows for displaying your data and also provides more advanced options such as showing track lines and enhanced attribute labeling.
Just like symbolizing standard feature layers, Tracking Analyst allows you to define the symbology for each individual tracking layer. However, you will notice that the Symbology tab on the Layer Properties dialog box has a unique look and feel for tracking layers. The following sections explain the unique options that exist for symbolizing tracking layers in Tracking Analyst.
Base symbology for events
Every tracking layer has a default symbol, referred to as the base symbol. This is similar to the symbol defined for any standard feature layer, except for one major difference. Tracking Analyst includes several symbology options that modify or override the base symbol. By default, none of these options are enabled and all the events in your tracking layer are displayed using the same base symbol. The base symbol for a tracking layer is defined on the default view of the Symbology tab (accessed by clicking Events in the Show panel). By default, the base symbology is a single symbol for all events, and it can be modified in the same way you would modify the symbol for a standard feature layer. As with a standard feature layer, more advanced options exist such as creating base symbology based on unique attribute values in your data.
Learn how to symbolize data based on unique attribute values
Time windows
Time windows are a powerful tool for displaying and analyzing tracking data. By allowing you to view only a subset of your data at any given time, time windows allow you to see your data changing through time.
Symbolizing most current events
Tracking Analyst allows you to assign special symbology for displaying the most current events in each track. This allows you to call attention to the most current positions of your tracked objects while still displaying older events. Symbology for most current events is set in the same way as base symbology, but it overrides the base symbology for the most current event in each track.
Learn how to symbolize most current events
To use this feature effectively, your tracking layer must have an appropriate track ID defined.
Symbolizing only the most current event in each track
Showing only the most current event for each track in a tracking layer is useful if you are only concerned with the current locations of objects. For example, if you are monitoring a fleet of vehicles in real-time, you might only be concerned with where the vehicles are right now. Using this feature, you could view only the most current location for each vehicle and hide all previous observations on the map display. This allows you to make quick decisions based only on the current locations of your vehicles.
Symbolizing only the most current events can also be useful for fixed-time data. When you play back fixed-time data using this feature, you see only one symbol representing each track.
 |
Learn how to display only the most current events in a layer
To use this feature effectively, your tracking layer must have an appropriate track ID defined.
Displaying future events
While in real-time mode and under most circumstances in playback mode, Tracking Analyst only displays events that occurred in the past. The Display Future Events option in the user interface above can be used to display events that exist in the future. This can be useful if you are dealing with sensitive real-time data and you want to make sure that no events are hidden from the display due to your system clock being out of sync with the time stamps contained in data streaming in from your tracking service.
This option can also be useful if you are working with fixed-time data that has time stamps in the future. For example, you might have a dataset containing the projected locations of satellites in the future. Normally, this future data would not appear if Playback Manager is closed (and therefore Tracking Analyst is in real-time mode), and this can cause confusion. Checking the Display Future Events check box makes all your future data appear when Playback Manager is closed. In playback mode, your future data appears based on the current time set by Playback Manager.
Symbolizing track lines
A track is a collection of events that share a common track identifier field, or track ID. A track line is a graphic line that connects those observations. For example, if all the observations of a single vehicle's position over time belong to a single track, a track line could be used to connect the dots and show the path of the vehicle. Track lines allow you to easily see the path followed by any tracked object.
Although track lines are most commonly used with point tracking layers, they can also be used for line and polygon tracking layers. When used with a line tracking layer, the track line connects the midpoints of each line feature. When used with a polygon tracking layer, the track line connects the centroids of each polygon feature.
The symbology used by your track lines can be customized in the same way as for a line feature class. However, it is important to understand that track lines are not features. They cannot be selected on the map nor used as input for other processes.
Learn how to symbolize track lines
To use this feature effectively, your tracking layer must have an appropriate track ID defined.
After you create track lines for a layer, the lines can be smoothed to create a more fluid and visually appealing display. In some cases, smooth track lines may also provide a more accurate estimation of the path followed by vehicles.
Symbolizing directional vectors
Directional vectors are arrows that indicate the direction in which a tracked object is heading and how fast it is going. Directional vectors can only be symbolized for point tracking layers. Directional vectors can be symbolized for all events in a tracking layer or only for the most current events from each track. In any case, the directional vector for each data point is calculated from two data points, the current data point and the previous point.
The length of a directional vector is expressed in units of time. For example, you can set the directional vectors for a tracking layer to be one minute long. This means that each directional vector would indicate where a tracked object is predicted to be one minute in the future if it stays on its current course at its current speed. Because directional vectors are calculated from only two data points, their accuracy depends on the accuracy of your data. They may not always truly represent the heading and speed of an object.
The symbology used by directional vectors can be customized in the same way as for a line feature class. However, it is important to understand that track lines are not features. They cannot be selected on the map or used as input for other processes.
Learn how to symbolize point data using directional vectors
To use this feature effectively, your tracking layer must have an appropriate track ID defined.
Labeling event attributes
In several tracking applications, such as aircraft tracking, it is useful to be able to label tracked objects with more than one attribute. For this reason, Tracking Analyst provides enhanced labeling for tracking layers. Up to six different attributes can be used to label each tracking feature. You can configure which attributes you want to display and specify the order in which they are displayed. You can also change the font used in labels and modify the positions of the labels relative to your features.
Labeling most current events
The enhanced labeling of Tracking Analyst can also be used to label only the most current events from each track. This is recommended when you only want to see one set of labels for each tracked object.
Learn how to label most current events with up to six attributes
To use this feature effectively, your tracking layer must have an appropriate track ID defined.
If your labeling needs are simpler than this, Tracking Analyst provides a quicker and easier way to label the most current events in your tracking layer with a single attribute. For example, if you are tracking a fleet of vehicles and you want to label the most current position of each vehicle with a vehicle name, this procedure would be recommended.
Learn how to label most current events with a single attribute
Using global symbology properties
Tracking Analyst provides the ability to set global properties for directional vectors and attribute labeling. Global properties are stored in your map document and define the default settings that are used for all tracking layers in the map document. If you do not want to use global properties, these symbology settings can be modified individually for each tracking layer. After you set the directional vector or event attribute properties for a single layer, you can always revert to the global properties for that layer with a single click.
Learn how to set global directional vector properties
Learn how to set global event attribute properties for labeling