Reviewing the entity types in CDB 1.2 and in GGDM/NAS, one substantive question is how to approach entity types that can either be freestanding objects in the outdoor environment or components, furniture, or fixtures inside building interiors.
Using themes to organize feature types particularly exposes this problem if we add separate themes for building interiors.
Option 1:
Should a separate entity type be present for exterior vs. interior versions of the same object, with the two versions assigned to different themes?
Option 2:
Should only one version of an entity type be defined for a particular conceptual item, but allow entity types to be assigned to more than one theme?
Consider:
Option 2 is more closely aligned with the upstream GGDM and NAS data model - NAS entities can be assigned to any number of themes - but is a change from the original CDB X proposed design. However, there may be cases where the indoor and outdoor versions of a feature may have substantial semantic differences where different types may be appropriate - this then gets into the name uniqueness issue.
As a purely practical matter this has limited impact on CDB content since building interior elements tend to be used in very different datasets than outdoor environment elements. However, if the different types should both exist, there should be clear semantic differences to know when to use each one.
Examples:
AL260 Wall vs. UK004 Wall_Generic (and subcodes) - but is an outdoor wall as a fortification/barrier the same as a structural wall for a building partition?
AL195 Ramp vs. UG017 Ramp - can be indoor or outdoor as well as attached to a building vs. freestanding, also can be an earthwork or natural terrain feature vs. constructed of masonry, wood, or metal
AQ150 Stair (GGDM) vs. AQ150 Stair_or_Step vs. UG018 Stair vs. UG022 Stair_Set - can be indoor or outdoor as well as attached to a building vs. freestanding
AL175 Courtyard (GGDM) vs. UG009 Courtyard - do these have same semantics? GGDM version includes both an outdoor area surrounded by a building as well as a generic courtyard bounded by walls and multiple buildings
General (will document later) - pretty much any piece of furniture, appliance, clutter, device, or equipment could either be freestanding outdoors vs. an element inside a room
Reviewing the entity types in CDB 1.2 and in GGDM/NAS, one substantive question is how to approach entity types that can either be freestanding objects in the outdoor environment or components, furniture, or fixtures inside building interiors.
Using themes to organize feature types particularly exposes this problem if we add separate themes for building interiors.
Option 1: Should a separate entity type be present for exterior vs. interior versions of the same object, with the two versions assigned to different themes?
Option 2: Should only one version of an entity type be defined for a particular conceptual item, but allow entity types to be assigned to more than one theme?
Consider: Option 2 is more closely aligned with the upstream GGDM and NAS data model - NAS entities can be assigned to any number of themes - but is a change from the original CDB X proposed design. However, there may be cases where the indoor and outdoor versions of a feature may have substantial semantic differences where different types may be appropriate - this then gets into the name uniqueness issue.
As a purely practical matter this has limited impact on CDB content since building interior elements tend to be used in very different datasets than outdoor environment elements. However, if the different types should both exist, there should be clear semantic differences to know when to use each one.
Examples: AL260 Wall vs. UK004 Wall_Generic (and subcodes) - but is an outdoor wall as a fortification/barrier the same as a structural wall for a building partition? AL195 Ramp vs. UG017 Ramp - can be indoor or outdoor as well as attached to a building vs. freestanding, also can be an earthwork or natural terrain feature vs. constructed of masonry, wood, or metal AQ150 Stair (GGDM) vs. AQ150 Stair_or_Step vs. UG018 Stair vs. UG022 Stair_Set - can be indoor or outdoor as well as attached to a building vs. freestanding AL175 Courtyard (GGDM) vs. UG009 Courtyard - do these have same semantics? GGDM version includes both an outdoor area surrounded by a building as well as a generic courtyard bounded by walls and multiple buildings General (will document later) - pretty much any piece of furniture, appliance, clutter, device, or equipment could either be freestanding outdoors vs. an element inside a room