Types of Object Based Data Models: Spaghetti Model and Vertex Dictionary Model (Especially for GATE-Geospatial 2022)

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1. Spaghetti Model

Spaghetti model is the simplest vector data structure. This model is the most natural and most logical model. In the spaghetti data model, each entity on a map becomes one logical record in the digital file, and is defined as a string of x, y coordinates. In this model the map is maintained as the conceptual entity. Each piece of analog map is considered as spaghetti and each piece of spaghetti acts as a single entity. Any polygons that lie adjacent polygons share the same string of spaghetti.

This Figure Shows Spaghetti Model

Advantages of Spaghetti Model

  • Good for computer-assisted cartographic production where no topologic relation is required.

Disadvantages of Spaghetti Model

  • No spatial relationships are reordered
  • Common boundary of two adjacent polygon are stored twice
  • Inefficient for most type of spatial analyses
  • Correction and updates of the data must rely on visual checks of graphic output.
  • Although all entities are spatially defined, no spatial relationships are encoded.

2. Vertex Dictionary Model

Vertex dictionary uses a similar approach as spaghetti but a smarter structure. It uses two files to store the vector data. The first file stores the vertices and the second file stores the description of objects as shown in figure.

Figure Shows Vertex Dictionary Mode

In this model, if some vertices are shared by two adjacent polygons, these vertices are not required to store twice. However, topological relationships are not well defined in this model. The problem of island polygon still exists. Therefore, it is reduced for data analysis and query.

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