Hello Jia
No worry for the delay. I'm often late myself.
Le 2023-11-20 à 05 h 56, Jia Yu a écrit :
the Sedona community will start to try the COG writer in late January
or early Feb 2024. By that time, we will drop the support of Java 8 to
be aligned with Apache SIS.
Thanks for the information. We can target a SIS 1.5 release in January
then. In the mean time, snapshots will continue to be pushed from time
to time on the Apache snapshot repositories. Please let me know if you
face issues.
In addition, do you have any plan to implement a native Java reader
and writer of PROJJSON string? (…snip…) We recently ran into a problem
in Sedona GeoParquet reader and writer: no existing pure Java library
that can read and write a CRS in PROJJSON format. However, PROJJSON
somehow is the CRS representation required by GeoParquet spec:
This is under discussion. PROJJSON is currently a format which is
specific to the PROJ project, not yet a standard. However, it has been
brought to the Open Geospatial Consortium (OGC) CRS Standard Working
Group (SWG) for standardization. I'm a member of this group and attended
to the initial discussion. The group is open to standardizing that
format, but may want to do some changes if they consider that some
aspects of PROJJSON are incorrect. On the other hand, PROJ is reluctant
to allow changes because PROJJSON is already used. In an attempt to find
an agreement, the CRS SWG has updated its charter as below:
/---- Quote from CRS SWG charter ----/
The new SWG work item is to define and support an encoding of the
self-contained and compact description of Coordinate Reference
Systems and Coordinate Operations through a simple JSON schema. The
draft standard delivered will be consistent with OGC Abstract
Specification Topic 2 and ISO 19111. This offers the following
advantages:
* Provides a JSON encoding of coordinate reference systems
descriptions for use where JSON may be considered a more natural
data schema than Well Known Text.
* Ensures that a JSON schema is available that will be kept in
alignment with OGC Abstract Specification Topic 2 and ISO 19111.
* Recognizing the PROJ6 origins of the PROJJSON schema
contribution being used as the starting point of this work,
effort will be made to try to avoid compatibility issues and to
clearly document any issues identified or object names that
deviate from the original OGC Abstract Specification Topic 2 and
ISO 19111. If an unresolvable conflict is identified, OGC
Abstract Specification Topic 2 and ISO 19111 will guide the
resolution and such an issue will be clearly documented.
/---- End of quote ----/
The CRS SWG has not yet started its work on a CRS JSON. In the last 10
years, progresses in CRS SWG were done a lot thanks to Roger Lott, who
has done a tremendous amount of work in editing ISO 19111 (a.k.a. OGC
Topic 2) and 19162 (a.k.a. WKT 2). For now Roger is busy with GGXF,
which is in final stage for becoming a standard. Maybe after that, we
will see progress in CRS JSON.
Meanwhile, GeoParquet is submitted for becoming an OGC standard, but is
not yet a standard. An OGC GeoParquet working group has been recently
created for that purpose. I joined that group as well, but did not yet
attended a meeting. I assume that the CRS representation in GeoParquet
will be a topic of some meetings. We do not know yet what will be the
group decision: will they keep PROJJSON unchanged? Wait for a CRS JSON
to be standardized before to standardize GeoParquet? Allow an
alternative encoding such as ISO 19162?
On Apache SIS side, some JSON parsing exists in the "incubator" group of
modules. The "incubator" group contains modules that are not yet part of
Apache SIS releases, because not considered mature yet. One of them is a
"Coverage JSON" module. The experience gained there may be used for a
"CRS JSON" support later. Another incubator module of potential interest
is a Shapefile reader and writer.
About the time frame: we applied to a GeoParquet funding made available
by OGC, with a proposal to do the development in Apache SIS.
https://www.ogc.org/requests/funding-available-for-creating-geoparquet-developer-resources/
If our submission is accepted, it would vastly speedup the development,
with at least a temporary solution for "CRS JSON" due in the time frame
of that project. If not accepted, we will probably try to do it anyway,
but it would take longer (we don't know how long).
Martin
