Open wiesehahn opened 2 months ago
So I just learned that "creation_year" and "creation_doy" are actually referring to the production time and not the aquisition time (see https://github.com/ASPRSorg/LAS/issues/138).
In this case I think populating datetime
derived from these attributes might at least be misleading. Although definition is vague too ("likely the aquisition time").
hi @wiesehahn yeah the LAS creation date is ambiguous unfortunately... It would be better to try to extract the datetime information from individual points, but then probably use start/end datetime rather than a single datetime, given that a single file may be composed of multiple swaths from different dates or weeks. Maybe this could be done with an extra command line option, and by default use just the header info.
populating datetime
with metadata from File Creation Day of Year
and File Creation Year
is even more confusing as there is an optional attribute created
(https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md#date-and-time) which would perfectly fit for those metadata.
So personally I would be definitely in favor of populating created
by File Creation Day of Year
and File Creation Year
. And get start_datetime
and end_datetime
(https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md#date-and-time-range) from timestamps of individual points if this would be possible in an efficient manner. I guess this also fits https://github.com/radiantearth/stac-spec/blob/master/best-practices.md#datetime-selection.
Then it would just be of question how to define datetime
? While this is not trivial e.g. same as start_datetime
or end_datetime
would fit better than creation date for most use-cases I guess
datetime
is defined aswhich is also assumed for vpc creation
However I am unsure if this is what "creation_year" and "creation_doy" are defined as (see https://github.com/ASPRSorg/LAS/issues/148) there it simply says
And from my experience this is what providers populate it with, the date at which the file was created after inital processing, so usually this is days to month later than the aquisition date.
In my understanding the definition is unclear and the implementation here is correct, however I am not sure.
Any thoughts on this?