Up to this point, we have not considered how geoinformation, such as fields and objects, is represented in a computer. Now that we have discussed the main characteristics of geographic phenomena (Learning path: Spatial Data modelling - Geographic Phenomena), let us examine computer representations in more detail.
Phenomena with intrinsic continuous and/or infinite characteristics therefore have to be represented with finite means (computer memory) for computer manipulation, yet any finite representation scheme is open to errors and interpretation. To allow for this, fields are usually implemented with a tessellation approach, and objects with a (topological) vector approach. In this learning path we will first discuss tessellations (regular and irregular) and vector-based representations and how these are applied to represent geographic fields and objects.
Tessellations can be regular or irregular. We will start with "Regular Tessellation" followed by "Irregular Tessellation".
Tessellations can be regular or irregular. We will now discuss the "Irregular Tessellation".
Tessellations do not explicitly store geo-references of the phenomena they represent. In vector representations, georeferences are explicitly associated with the geographic phenomena. Examples of vector representation are discussed in the next concepts.
Examples of vector representations are discussed in the next concepts. To start, we will examine the TIN representation for geographic fields, which is a hybrid between tessellations and vector representations.
The next vector representation to be discussed is the "Point representation".
In vector representations, lines are used to represent one-dimensional objects.
In the next concept we will discuss Area representations. Areas can be represented with and without topology. The Topological area data model will be discussed in the next Learning path (Spatial Data Modelling - Topology and Time).