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 spatial reference frame in a given transmittal. In other words, an <Environment Root> is the starting point for all objects in the same spatial reference frame in a transmittal.

Primary Page in DRM Diagram:

• 1

Secondary Pages in DRM Diagram:

• 3
• 8
• 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>.

As a data provider, may I supply multiple <Environment Root> instances in the same transmittal?

Yes, provided that each <Environment Root> instance has a distinct srf_parameters 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

• <<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 Domain> instance (notes)

Composed of (two-way metadata)

• zero or one <Access> instance
• zero or more <Browse Media> instances
• zero or one <Citation> instance
• zero or more <Cross Reference> instances
• zero or one <Data Quality> instance
• zero or one <Description> instance
• zero or one <Keywords> instance
• zero or one <Point Of Contact> instance

Component of (two-way)

• one <Transmittal Root> instance

Inherited Field Elements

Field Elements

Notes

Composed of Notes

Base_Time_Data

 If different than the <Transmittal Root>'s <Base Time Data>

Hierarchy_Summary_Item

 Dependent on the <Feature Hierarchy> and <Geometry Hierarchy>
 components. See constraint
 <Hierarchy Summary Item For Environment Root and Models> for
 details.

 Briefly,

 1. If only a <Feature Hierarchy> is present, then at most one
    <Hierarchy Summary Item> instance may be present, namely,
    one which describes the <Feature Hierarchy>.

 2. If only a <Geometry Hierarchy> is present, then at most one
    <Hierarchy Summary Item> instance may be present, namely,
    one which describes the <Geometry Hierarchy>.

 3. If both a <Feature Hierarchy> and a <Geometry Hierarchy>
    are present, then each may have a corresponding
    <Hierarchy Summary Item> instance. It is permissible in
    this case for only one <Hierarchy Summary Item> instance
    to be present which corresponds to one of the two
    hierarchies, but if two <Hierarchy Summary Items> are
    present, then one shall correspond to the <Feature Hierarchy>
    and the other to the <Geometry Hierarchy>.

Interface_Template

 Provides access to all <Variables> defined within the scope of
 the <Environment Root>, if any. If there are such <Variables>,
 an <Interface Template> shall be present; otherwise, it shall
 not be present.

Spatial_Domain

 The spatial extent of the <Environment Root> - defines the maximum
 spatial extents of the component objects