clause-4-change-log.adoc

Change Log

Notes on the "meaning" of column headings.

• Source - Source of the change. In the case of the I3S Community Standard, the value is always "Other" indicating that the changes were submitted from an external source.

• Identifier - As the changes to the I3S Community Standards were submitted by the Esri I3S community, there are no Change Request or GitHub issue identifiers. Hence the value used in this document is N.A. for Not Applicable.

• Type - Type of change. Always "A" for administrative.

• Section - The section number modified in the updated document.

• Description - Brief text describing the change.

• Purpose - the reason for the change. Suggested reasons are:

  • Clarity

  • Consistency

  • Deprecated

  • Interoperability

  • Perfunctory

  • Readability

  • Usability

A word on "deprecated". For the purposes of this I3S revision, deprecated properties do not impact backwards compatibility. Deprecated properties in version 1.1 were optional in version 1.0. Further, these deprecated classes/properties will remain in the OGC I3S Community Standard until such time as Version 2 of this Community Standard is approved. At that time, this deprecated class will be removed from the standard. This will aloow adequate time for any I3S implementations to remove deprecated elements from their product and applications.

Change Table

Table 1. Change Log

Source	Identifier	Type	Section	Description	Purpose
Other	N.A.	A	Introduction	Added additional informative text to the first and second paragraph. Add Point Clouds to the bullet list.	New informative content
Other	N.A.	A	3.0 Terms and Definitions	Added an additional informative sentence to Term 4.11 Oriented Bounding Box. In support of the new Point Clouds Layer type, added terms and definitions for LiDAR, Near Infrared, and Point Clouds	New informative content
Other	N.A.	A	Section 6.1	Reworded all the design principals.	Readability and Clarity
Other	N.A.	A	Section 6.2	Reworded the Overview to enhance “readability” Added Point Clouds to the bullet list and to Table 1.	Readability and Clarity
Other	N.A.	A	Section 7.1 Coordinate Reference Systems	Added a new introductory informative paragraph for clarification and to reduce complexity in the text	Clarity
Other	N.A.	A	Section 7.1.2 CRS use and requirements in I3S	Add the clarifying sentence: “Note that all I3S profiles support writing 3D content in two modes: global and local. In global mode, only the geographic CRS WGS84 (EPSG 4326) is supported for both index and vertex positions.”	Clarity
Other	N.A.	A	Section 7.3.1 I3S - Indexing Model and Tree Structure	A number of grammatical changes to improve flow and “readability”.	Readability
Other	N.A.	A	Section 7.3.2 Geometry Model and Storage	A number of grammatical changes to improve document flow and “readability”.	Clarity and readability.
Other	N.A.	A	Section 7.3.3 Textures	A few edits that improve document flow and “readability” were applied.	Readability
Other	N.A.	A	7.3.4 Attribute Model and Storage	A few edits that improve document flow and “readability” were applied. Links to related attribute classes were added.	Interoperability and Readability
Other	N.A.	A	7.5 Level of Detail	A few edits that improve document flow and “readability” were applied.	Readability
Other	N.A.	A	7.5.1 Discrete LoDs	A few edits that improve document flow and “readability” were applied.	Readability
Other	N.A.	A	7.5.2 Representation of input data	A few edits that improve document flow and “readability” were applied.	Readability
Other	N.A.	A	Section 7.5.3.1 Node Switching	Added the following informative paragraph clarifying what node switching is: Node switching lets clients focus on the display of a node as a whole. A node switch occurs when the content from a node’s children is used to replace the content of an existing node. This can include features, geometry, attributes and textures. Node switching can be helpful when the user needs to see more detailed information.	Clarity
Other	N.A.	A	Section 7.5.4 Levels of Detail Generation	Reformatted Table 2 to be consistent and to include Point Cloud Layers and (planned) Building Scene Layers.	Interoperability
Other	N.A.	A	Section 7.5.4.7 (now 7.6.4.7) Class IndexScheme	This class has been deprecated in the version 1.1 of the OGC I3S Community Standard. However, this class remains in the standard for backwards compatibility. Developers should not implement this class. This class will be removed in a future I3S version. See additional note below table.	Deprecated
Other	N.A.	A	Section 7.5.5 LoD Selection Metrics	Corrected an error in the example. Added definitions for maxScreenThresholdSQ, maxScreenThresholdSQ, screenSpaceRelative, distanceRangeFromDefaultCamera, effectiveDensity. The latter two definitions are new in version 1.1 of the OGC document. They were added in support of Point Clouds. Added a new table to better summarize available properties.	Clarity and Enhancement. See Substabtive Changes for more information
Other	N.A.	A	7.6.3.1 Class SceneServiceInfo	A few edits that improve document flow and “readability” were applied.	Readability
Other	N.A.	A	7.6.4.1 Class 3dSceneLayerInfo	Added a sentence to clarify the relationship between this class and sub-class drawingInfo.	Clarity. See also Substantive Changes for more information.
Other	N.A.	A	7.6.4.2 Class Store	Added more informative text for the resourcePattern property. Old description was limited and confusing. Added more informative text for the normalReferenceFrame property. Old description was limited and confusing. Added more informative text for the lodType property. Old description was limited and confusing. Added more informative text for lodType value descriptions (MeshPryamid, AutoThinning, Clustering, and Generalizing)	Clarity
Other	N.A.	A	7.6.4.2 Class Store	The property indexScheme was deprecated. This was an optional property	Deprecated
Other	N.A.	A	7.6.4.3 GeometryStore	Renamed as this class was incorrectly labeled in version 1.0. The class name should have been defaultGeometrySchema. Added more informative text for the topology property. Old description was limited and confusing	Clarity and Interoperability
Other	N.A.	A	7.6.5.1 3dNodeIndexDocument	Updated table of properties to include property “obb”, which is new for this revision. Corrected an error in the clause title. In version 1.0, the title stated, “Node”. This should have been 3dNodeIndexDocument. All examples and other references were correct in version 1.0.	Clarity and Interoperability
Other	N.A.	A	7.6.5.2 nodeReference	Updated table of properties to include property “obb”, which is new for this revision.	Interoperability
Other	N.A.	A	7.6.5.4 Class Feature	This class is deprecated in version 1.1. FeatureData contains the properties originally in class Feature.	Deprecated
Other	N.A.	A	7.6.5.5 Class LodSelection	The maxValue, avgValue, and minValue properties have been deprecated in version 1.1. These were optional properties. See additional note below table.	Deprecated
Other	N.A.	A	7.6.6 FeatureData	Added reference to Point Clouds	See Substantive Changes for more information.
Other	N.A.	A	7.6.6.5 Class GeometryReferenceParams	Added a new optional property called “type”. The type denotes whether the following geometry is defined by using array buffer views (ArrayBufferView), as an internal reference (GeometryReference), as a reference to a shared Resource (SharedResourceReference) or embedded (Embedded).	Interoperability
Other	N.A.	A	7.7.1.2 Class Texture	Added the ‘image’ property and reference to the ‘image class’ as this was missing from the table of properties in version 1.0 of the Community Standard.	Interoperability
Other	N.A.	A	7.7.1.4 Class Renderer	Added informative text to better define UniqueValue and ClassBreaks	Clarity.
Other	N.A.	A	8.1 Textures and all subsections	A number of minor grammatical edits for clarity and additions to the informative content are incorporated.	Clarity and Readability
Other	N.A.	A	8.3 Attributes including 8.3.1 and related sub-clauses	A number of minor grammatical edits for clarity and additions to the informative content are incorporated.	Clarity and Readability
Other	N.A.	A	8.3.2 REST API for Accessing Attribute Resources	Minor grammatical edits were made.	Readability
Other	N.A.	A	8.3.3 A typical usage pattern of the attributes REST API	Minor grammatical edits were made. Also, the attributeStorageInfo properties originally listed as bullets are now organized into a table for clarity and are available in clause 7.6.4.6.	Clarity and Readability
Other	N.A.	A	8.3.4 Attribute Resources: Details	Minor grammatical edits were made.	Readability
Other	N.A.	A	9.0 New chapter that provides details on the I3S Layer Structures	A variety of information on the various layer structures, such as Point Scene Layers, were scattered through the document and in the annexes. Further, there were no examples. Version 1.1 now provides details and implementation examples for each of the supported layer types. More information is provided below.	Clarity, Readability, Interoperability
Other	N.A.	A	10.1 (Was 9.1) Flexibility	Minor grammatical edits were made for clarity.	Clarity
Other	N.A.	A	10.2 (Was 9.2) Summary of I3S Defining Characteristics	Minor grammatical edits were made for clarity.	Clarity
Other	N.A.	A	11 (Was 10.0) Persistence	Minor grammatical edits were made for clarity.	Clarity

Additional Note on deprecated properties in Class LodSelection

The maxValue, avgValue, and minValue properties in Class LodSelection are deprecated. The LodSelection object provides information on a given metric determined during the cooking process of an I3S store. This metric can be used by the client to determine whether a representation is of the right quality level for rendering or whether a different representation is needed.

Publishers (aka “cookers”) can add as many LodSelection objects as desired but must provide one so the layer’s lodType is not null.

Additional Note on IndexScheme

The IndexScheme class has been deprecated as the class was useful only for informational reasons. Furthermore, it made it onerous for content generators to explicitly document the data partitioning scheme used to generate an I3S content. As an I3S client’s data discovery and traversal is purely driven by the node index document, information supplied by the IndexScheme class is not necessary for traversal or for efficient loading of content. As a result, this class is deprecated.