1) Geographical visualization
The geographical visualization is performed using the dataset DS’ by layers with icons and arrows over Google Map (using Google Maps API v.3) (Fig.7). The arrows are used for indication of the chronicle order and the direction of the container movements. Helmet [32] summarizes in his study that the arrows are the perfect way for presenting lineal structure of data and for presenting different characteristics in multidimensional data, good practice is the usage of different colors, icons. That’s why we use different icons indicating different characteristic of the container during its travel. The center of the map and the zoom are calculated in order to include all the locations of the container movement data. The visualization of the arrow layer is optional and the user controls it by the check-box. The icons present each location from the extracted container dataset and the numbers and filling indicate for the sequence number of the location in the extracted container history and the container status at this location. Only one hundred numbered icons are used, so if the requested container history contains more than 100 locations, the location after the 100th are drown by black icon without number. This limitation is accepted because a trajectory with more than 100 locations is non-understandable. When the user moves over some icon, a little info-window is visualized showing the name of the location (Fig.7), when the mouse is over arrow – another info-window showing info for the departure and destination location is shown.
For each icon an info-window is available after click on the icon (Fig.8). This info-window includes detailed information about the events and status of the container at this location, and the date range of the stay.
Figure 7. Container history visualization.
More detailed information is available in the tab “Details for Selected Location” (Fig.8) where the user can see: listing of all vessels, voyages, carriers, involved in event(s) at the selected locations, previous and next few locations (the current location is highlighted with a green background) and geographical details for the location.
Figure 8. Detailed information for selected location.
The location listing can be used by the user for visualization of sub-set of the extracted container history, called sub-history. Once the container history has been extracted for the specific period of time, the user can define a sub-history for geographical reviewing by selecting a location target in the location listing (Fig.9). The target is presented by blue background in the location listing and in the geographical visualization by a red icon with the sequence number of the corresponding location in the selected sub-history. A target can be only a clean location. The sub-history is determined by three parameters – target, position of the target in the sub-history and length of the sub-history. All of them are user defined. The length of the sub-history in the current version of