Playback

Owned by Isabelle Avery (Unlicensed)
Last updated: Jan 04, 2023 by Charlotte Dakin-Norris
5 min read

Introduction

This section discusses the Playback tab, and it's ability to examine a diverse range of data from the ClearWay™ and AdvanceGuard® systems.

The purpose of the Playback tab is to query, review, analyse, and compare all track, alarm, carriageway/area and system data. The results can then be used for traffic analysis, for finding patterns of behaviour, for making data predictions, for extracting specific statistics, and as evidence of past incidents. Data results are presented in result tables as well as graphs for clear, visual data absorption and understanding.

Contents

Running a Query

There are four steps to running a query:

  1. Select the Time Period - use a time preset, the Time Bar or a custom date range to select a time period over which to query the database.

  2. Select the Query Type - select one or more query types to run.

  3. Select the Query Filters - for each selected query type, apply any required filter criteria.

  4. Run the Query - run the query and analyse the result. You can now refine the search criteria and repeat the process if required.

Selecting the Time Period

The first step is to select the time period. There are several ways to select the time period using the options available on the Time Bar. By default the time period is set for the last hour, so if this is adequate then you are ready to go.

Time Bar

Time Presets: Select a quick time period preset. All the presets represent a time from now into the past for the period selected. For example selecting 1h will search for data over the last hour from the time the preset was selected.

Custom Time Period: Select Custom to set a user-defined start and end time for the query

Time Bar: Use the time bar to visually select a start and end time. Each end of the selection can be dragged with the mouse to increase or reduce the time, and the entire time window can be moved by using Ctrl+Drag.

Selected Time: This represents the start and end time based on the currently selected period, regardless of which option was used to select it.

Time Scale: This option sets the scale of the Time Bar. This value sets the total amount of time visible on the Time Bar.

Which ever option is used to select the start and end times, the resulting time period will be displayed on the Time Bar. So even if you start with a preset you can still make further adjustments on the Time Bar as required.

Selecting the Query Types

All the available query types are listed in the left hand panel. To select one or more queries to run, you must select the check box next to the query name. In the illustration below both the System Log Query and Alarm Query have been selected. When the query is run, it will search for both types of data within the selected time frame.

When you select a query type, this automatically exposes the filter criteria which are applicable for the selected query. Typically queries do not have any default filters so they will return all data for the selected time period. By applying filters you will be reducing the amount of data returned which should make the query faster and help you find your results much easier.

Selecting the Query Filters

Once you have selected the query types, the individual filters for each query are available to set as required. Each query will offer filters which are applicable to the data being searched. Some query filters are quite complex and involve several layers, for example, using a carriageway as a filter in a ClearWay™ query will offer additional filters to select one or more sections, if required.

Complete the query filters details as required. Remember filters parameters can be easily changed and the query re-run.

Note that all selected filter criteria are used together with AND logic, which means all the conditions selected in the filters must match for the data be returned. If you are struggling to find data, you can relax the search criteria by removing filters so more data is returned.

Running the Query

Once you have set all the required query filters you can run the query by selecting the Query button.

Query Results

By default the results are limited to 5000 records. If the query would have returned more data then you will only see the first 5000 results. However you can adjust this limit using the Record Limit slider.

Increasing this limit to its maximum may have a detrimental impact of system performance, particularly on busy systems with large databases. We also recommend user a lower limit with targeted filters to ensure you return the minimum amount of data required.

Depending on the type and number of queries you selected you will get a number of results. These will typically take the form of a results list, but may also include graphs to help visualise the data. Each selected query will generate its own results set.

Query Types

The query types vary from depending on whether you are using AdvanceGuard® or ClearWay™. However there are a number of queries common to both products:

AdvanceGuard® & ClearWay™ :

  • Alarm Locations AG & CW

  • False Alarms AG & CW

  • Alarm Query AG & CW

Log Queries

  • Audit Log Query

  • System Log Query

System Alarm Query -

False Alarm Tracks -

& :

  • Track Query

  • ATI AG & CW

  • Lost AG & CW

ClearWay™ Specific Queries:

:

  • Carriageway Statistics

  • Carriageway Traffic Analysis

  • Highways Log Query

Exporting Results

Most data can be exported as CSV by selecting the Export button on the relevant results panel. For example alarm results can be exported as CSV by selecting the Export button from the Alarm result list.

 

Safety is everything.