The SEDRIS Data Representation Model
APPENDIX A - Classes
Property Value

Class Name: Property Value

Superclass - <Property>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies a property of the attributed DRM object and its value in terms of

  1. its meaning (specified using an EAC, SE_Index_Code, or SE_Variable_Code),
  2. its unit of measurement (such as metres),
  3. and its data storage type (such as EDCS_Integer).

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

Example

  1. The <Property Value> instances of a representation of a lake might include the EAC_SURFACE_MATERIAL_TYPE of the lake.

  2. Consider the man-made materials that can be found on any surface, such as cloth, carpet, asphalt, silk, metal, and natural materials, such as wood. To specify the material making up a wooden wall represented by a <Polygon> instance, the data provider represents it as depicted in Figure 6.48.

    Property Value, Example 1

    Figure 48 — <DRM Property Value> example

  3. Consider an <Areal Feature> instance representing a surface covered with vegetation. To specify the type of vegetation, the data provider gave it a <Property Value> component with a meaning of EAC_VEGETATION_TYPE, and the value specifying the exact type of vegetation.

  4. Consider an <Areal Feature> instance labeled as "Red Field", because the surface represented has clay soil present. To describe the soil composition at some point or for some surface, <Property Value> instances are used, so a <Property Value> instance of the appropriate attribute is attached to the <Areal Feature> instance.

  5. Consider acoustic response (that is, changes to characteristics of objects in response to acoustic stimuli) such as the resonant frequency of a plate, response (such as echo, phase shift, absorption, diffraction), or frequency.

  6. Consider electromagnetic emission, that is, the emission characteristics of a geometric object or feature, including the electromagnetic wavelengths, amplitudes, and directionality. Examples include

    1. The thermal signature of a rock at noon is described by its electromagnetic emission.
    2. The headlight of a truck.
  7. Consider electromagnetic response (that is, changes to characteristics of objects in response to electromagnetic stimuli). Some examples of such properties include reflective and specular characteristics of a surface.

  8. Consider hydrology (that is, an attribute describing some aspect of the flow of water at a location or on a surface). For the <Polygon> instances that represent Salmon Creek, an example hydrology property represented by <Property Value> instances is the average speed of currents in the stream bed.

  9. <Property Value> instances can provide metrics or measurements that relate to scalar properties, such as the elevation at a particular location.

FAQs

No FAQs supplied.

Constraints

Composed of (two-way) (inherited)

Component of (two-way)

Inherited Field Elements

SE_Property_Code meaning; 1
SE_Boolean apply_property_inheritance; 2

Field Elements

EDCS_Attribute_Value value; 3

Notes

Fields Notes

meaning

The meaning field specifies the meaning of the <Property> instance.

apply_property_inheritance

If apply_property_inheritance is SE_TRUE for the <Property> instance P, P shall be inherited; otherwise, P shall not be inherited.

value

The value field specifies the value of the given property.


Prev: Property Table Reference Control Link. Next: Proximity Data. Up:Index.

Last updated: July 26, 2006 Copyright © 2006 SEDRIS