Event (Table) Type

Events are divided into point events and line events, which are respectively stored in a point event table and a line event table.

• Point Events and Point Event Table

  A point event occurs at a precise point on the route. For example, traffic accidents on highways, speed measuring instruments on expressways, bus stops, valves on pipelines, etc. In the point event table, each point event corresponds to a route ID (route identification field), and a field is used to store the location describing the point event, namely the scale field.

  of point events

  Figure: Schematic diagram

• Line Event and Line Event Table

  A wire event occurs on a segment of a route. For example, the paving material of a section of road, traffic congestion, the diameter of the pipeline, the section where the collapse occurred, etc. As shown in the following figure, in the line event table, each line event must contain a route ID (route identification field), and the start and end scale fields are used to store the location describing the event.

  Figure: Line Event Intent

  Start Scale Field: is used to store the scale value corresponding to the start point of the line event on the route.

  End Scale Field: is used to store the corresponding scale value of the end point of the line event on the route.

Generate Event Table

Generate Event Table is the process of generating a property table containing point or line events. The event table can be entered manually, or it can be combined with the Route Dataset Generate Event Table through an existing point or Line Dataset.

According to the different types of generated events, it can be divided into the generation of point event table and the generation of line event table.

• Build Point Event Table A point event table is generated

  from the point data and Route Data. Generate a buffer area for LineM according to the specified search radius. This area is called the search range. The points that fall within this area are used in the Generate Event Table, and each point corresponds to an event. Finding points outside the range does not generate an event. For the generated point data, two Property Fields will be added to store the route ID and M value respectively.

  of point event table generation

  Figure: Schematic diagram

• Generate Line Event Table Similar

  to the point event representation generation, a line event is generated for each line if the line object falls completely within the search range. The Property Field contains the route ID, the scale value of the line start point, and the scale value of the line end point. Line objects that do not fall or partially fall within the search range do not generate line events. The following figure is a schematic diagram for generating the line event table. The maximum straight-line distance from the line L2 to the route is greater than search radius, so the corresponding event will not be generated.

  of line event table generation

  Figure: Schematic diagram