Documentation request: Unclear on constraints/expectations for channel names/units
Hi, this is a companion issue to #227 (closed), but here I'm asking about channels rather than axes.
- Is there a limit on the number of different "full-sized" channels (e.g. 3D for a dataset with 3 dimensions) that may be written to a VDS dataset?
- All the datasets that I see have "Amplitude" as the primary channel (channel 0) name. Is it legal to have a dataset where "Amplitude" is not the primary channel, or where it is not present at all?
- The datasets imported from SEGY all seem to have auxiliary "Trace" and "PDSTraceHeader" channels with per-trace values. Is it legal to create datasets that do not have those channels?
- What are the constraints on the names of channels?
- Are they restricted to solely the names #define'd in
GlobalMetadataCommon.h
in section "Attributes' names"? - Or, are they allowed to be any alphanumeric ASCII string?
- Or, are additional printable ASCII characters allowed as well (which ones?)?
- Or, is any printable string allowed? (Is the encoding required to be UTF-8 or something else?)
- Are they restricted to solely the names #define'd in
- What are the constraints on the units of channels?
- Are they restricted to solely the names #define'd in
KnownMetadata.h
withKNOWNMETADATA_UNIT_
prefixes / accessible from theKnownUnitNames
class? - Or, are they allowed to be any alphanumeric ASCII string? (And if so, is that round-trippable?)
- Etc.
- Are they restricted to solely the names #define'd in
As a motivation for this question, I might have need to create a channel named "Density" whose units are "g/cm^3" for instance. Or a channel named "Temperature" whose units are "degrees C", or "Salinity" with units "ppm". These are just examples off the top of my head, our own internal file formats allow for near-arbitrary channel names and units.
Thank you in advance for whatever information you can provide!