====== The Spatial Information Object ======

Vector data represents geography as a collection of discrete identifiable units or objects. In Orbit Technology, every single object is considered as an **Spatial Information Object** or **SIO**. 
A Spatial Information Object consists of two components:
  * **Spatial Component**
  * **Attribute Component**

===== Spatial Component =====

A Spatial Information Object refers to a feature in reality,  by considering those features as geometrical shapes. Three types of geometry are distinguished:
  * **Points**
  * **Lines**
  * **Areas (polygons)**

==== The Object ====

The Spatial Component of an object is a series of coordinates that together form a figure. In most cases, this is a single figure. 

{{:technologies:basic_concepts:sio-spatialcomp.png?800&nolink|}}

==== Parts of an Object ====

This list of coordinates can form more than one figure. These single figures within an object are called Parts. 
For example an object of type area with 2 parts. The inner part excludes a portion from the outer part, creating a so called donut. 
An object (Point, Line, Area) can have an unlimited amount of parts, each of from the same Model-type (Point, Line or Area)

{{:technologies:basic_concepts:sio-spatialcompmulti.png?800&nolink|}}

==== Segments ====

Segments are portions of a part, a pair of coordinates. They do not appear as such in the coordinate list, but are used in some functions to work with a portion of a part rather than the whole part or the object.
For example the 'Delete' function exists in all varieties : delete object, delete part, delete segment, remove point.

===== Attribute Component =====

The Attribute Component holds the descriptive data in tabular form. This consists out of one or more Attribute Sets (or Attribute Tables) which is the equivalent of a table definition : a range of fields with their datatype definition.
For each Attribute Set, the Attribute Component can hold one or more data rows. Each row contains a value for each field in the Attribute Set.
{{:technologies:basic_concepts:sio-attributecomp.png?800&nolink|}}