The Place Object allows the provision of a unit, which presumably modifies the interpretation of its altitude field. However, this relationship is not specified in the text and no default unit is provided.
I suggest the need for a Place primer topic stating that unit modifies altitude. If producers provide an altitude, then unit is a required field and must be provided. If no altitude is provided, unit must not appear. However, if altitude is provided without a unit, readers may assume the default value meters.
It should also be stated that altitude should be interpreted as distance above, or below, mean sea level on Earth rather than distance relative to the surface at the given latitude/longitude or any other point. (Note: This assumption, while appropriate for altitudes on Earth, would not apply on non-Earth bodies that typically have no "sea-level.")
Finally, I suggest that it be stated that latitude, longitude, and altitude, as defined in the current version of the vocabulary, apply only to places which are on the planet Earth. And, it would be useful to clarify that the coordinate reference system for latitude and longitude is EPSG:4326; the EPSG code for WGS84.
Note: I am preparing a FEP to define an extension defining a new crs field that would provide for specification of the coordination reference system to be used in interpreting these values. This extension would allow the use of alternative CRS's on Earth as well as extend the use of Place to the description of locations on non-Earth bodies.
Please Indicate One:
Please Describe the Issue:
The Place Object allows the provision of a
unit
, which presumably modifies the interpretation of itsaltitude
field. However, this relationship is not specified in the text and no default unit is provided.I suggest the need for a
Place
primer topic stating thatunit
modifiesaltitude.
If producers provide analtitude
, thenunit
is a required field and must be provided. If noaltitude
is provided,unit
must not appear. However, ifaltitude
is provided without aunit
, readers may assume the default valuemeters.
It should also be stated that
altitude
should be interpreted as distance above, or below, mean sea level on Earth rather than distance relative to the surface at the given latitude/longitude or any other point. (Note: This assumption, while appropriate for altitudes on Earth, would not apply on non-Earth bodies that typically have no "sea-level.")Finally, I suggest that it be stated that
latitude
,longitude
, andaltitude
, as defined in the current version of the vocabulary, apply only to places which are on the planet Earth. And, it would be useful to clarify that the coordinate reference system forlatitude
andlongitude
is EPSG:4326; the EPSG code for WGS84.Note: I am preparing a FEP to define an extension defining a new
crs
field that would provide for specification of the coordination reference system to be used in interpreting these values. This extension would allow the use of alternative CRS's on Earth as well as extend the use ofPlace
to the description of locations on non-Earth bodies.