Data Hierarchy

The data in Vulcan is structured into five levels:

Design Files Layer Object Coordinates

  1. At the topmost level is your current working directory. This is the folder from which you start Vulcan.
  2. Each folder is divided into various design databases. Each design database may contain data relating to single map sheets covering the same defined area (see Creating a Job Specification File ). Alternatively, a file may be dedicated to a particular type of data, for example contours, roads or to a particular discipline, for example geology, survey.

    In any Vulcan session, the contents of all files may be edited, underlayed (as a non-editable layer), or composited to create new data files.
  3. Each database is divided into logical data groups called layers. A layer usually brings together a group of similar objects and data. For example, in a file representing a map sheet, all 200 metre contours may be in one layer and 100 metre contours in another layer. Vulcan also reserves special layers for its own use.
  4. Layers in turn are divided into graphical entities which are called objects. An object usually defines a physical feature, such as a single contour string or a block of annotation text. It is at the object level that graphical attributes, such as colour, line type and pattern fill, are defined.
  5. The final level is the individual coordinate point or line of text in the object. Each point or text line may be independently edited.

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