Class Name: Environment Root

Superclass - <SEDRIS Abstract Base>

Subclasses

Definition

An instance of this DRM class is the aggregating object for the <Feature Hierarchy> and / or <Geometry Hierarchy> that represent the instantiation of a collection of all data in a common SRF in a given transmittal. In other words, an <Environment Root> instance is the starting point for all objects in the same SRF in a transmittal.

Primary Page in DRM Diagram:

• 1

Secondary Pages in DRM Diagram:

• 16

Example

1. Earth.

2. An area of North America that straddles two UTM zones. The <Transmittal Root> would have two <Environment Root> components, one for each of the two UTM zones.

FAQs

Is an <Environment Root> required in a transmittal?

No. For example, a valid transmittal may contain only libraries, such as a <Transmittal Root> with a <Model Library> but without an <Environment Root>.

May a data provider supply multiple <Environment Root> instances in the same transmittal?

Yes, provided that each <Environment Root> instance has a distinct srf_info field (in accordance with the constraint <<Environment Root Spatial Reference Frame>>). See example 2.

Why can <Environment Root> have at most 2 <Hierarchy Summary Item> components?

See <<Hierarchy Summary Constraints>>.

Can <Environment Root> have both <Hierarchy Summary Item> and <Primitive Summary Item> components (as opposed to either/or)?

Yes.

Constraints

• <<Publishable Object>>
• <<Environment Root Spatial Reference Frame>>
• <<Hierarchy Summary Constraints>>
• <<Non Empty Environment Root>>

Composed of (two-way)

• zero or more <Base Time Data> instances (notes)
• zero or one <Feature Hierarchy> instance
• zero or one <Geometry Hierarchy> instance
• a bounded set of 0..2 <Hierarchy Summary Item> instances (notes)
• zero or one <Interface Template> instance (notes)
• zero or more <Primitive Summary Item> instances
• one <Spatial Extent> instance (notes)

Composed of (two-way metadata)

• zero or one <Access> instance
• zero or one <Citation> instance
• zero or more <Cross Reference> instances
• zero or one <Data Quality> instance
• zero or one <Description> instance

Component of (two-way)

• one <Transmittal Root> instance

Inherited Field Elements

Field Elements

Notes

Composed of Notes

Base_Time_Data

 These components are present only if they differ from the
 <Base Time Data> of the given <Environment Root> instance's
 <Transmittal Root> aggregate.

Hierarchy_Summary_Item

 The presence of these components depends on the <Feature Hierarchy>
 and <Geometry Hierarchy> components. See
 <<Hierarchy Summary Constraints>> for details.

Interface_Template

 If present, this provides access to all <Variable> instances
 defined within the scope of the given <Environment Root> instance,
 if any. If there are such <Variable> instances, an
 <Interface Template> shall be present; otherwise, it shall
 not be present.

Spatial_Extent

 This specifies the spatial extent of the given <Environment Root>
 instance, defining the maximum spatial extents of the component
 objects.

Fields Notes

srf_info

 The srf_info field specifies the SRF within which the given
 <Environment Root> instance is defined.