Hi all: as part of working on OGC API - Coverages support in pygeoapi, I'm writing the equivalent of what WCS GetCoverage would do; that is, clip by bbox and subset by bands if requested.

An initial implementation can be found in this branch.

At the moment, the data is returned as JSON-ified ndarrays. I would like to return the data in its native format. What would be a general approach here? Would one use a MemoryFile, write to it, and then read it back to the caller?

Thanks

..Tom

(sorry, just getting back to this!)

Thanks Sean. Indeed the MemoryFile strategy works as expected:

import sys

import rasterio
from rasterio.io import MemoryFile

with rasterio.open(sys.argv[1]) as src:
    with MemoryFile() as memfile:
        profile = src.profile
        with memfile.open(**profile) as dest:
            dest.write(src.read())

Are there any known issues with reading/subsetting, and writing back a NetCDF via MemoryFile? Traceback:

(pygeoapi) (base) tomkralidis@aruba:~/Dev/pygeoapi/pygeoapi-tomkralidis$ python dd.py tests/data/CMIP5_rcp8.5_annual_abs_latlon1x1_PCP_pctl25_P1Y.nc 
Traceback (most recent call last):
  File "rasterio/_io.pyx", line 1135, in rasterio._io.DatasetWriterBase.__init__
  File "rasterio/_err.pyx", line 205, in rasterio._err.exc_wrap_pointer
rasterio._err.CPLE_OpenFailedError: Unable to create netCDF file /vsimem/fa663a74-d548-494d-a2ab-880bdff831c4/fa663a74-d548-494d-a2ab-880bdff831c4. (Error code 2): No such file or directory .

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "dd.py", line 9, in <module>
    with memfile.open(**profile) as dest:
  File "/Users/tomkralidis/opt/miniconda3/lib/python3.7/site-packages/rasterio/env.py", line 382, in wrapper
    return f(*args, **kwds)
  File "/Users/tomkralidis/opt/miniconda3/lib/python3.7/site-packages/rasterio/io.py", line 136, in open
    nodata=nodata, sharing=sharing, **kwargs)
  File "rasterio/_io.pyx", line 1139, in rasterio._io.DatasetWriterBase.__init__
rasterio.errors.RasterioIOError: Unable to create netCDF file /vsimem/fa663a74-d548-494d-a2ab-880bdff831c4/fa663a74-d548-494d-a2ab-880bdff831c4. (Error code 2): No such file or directory .

Versions:

>>> import rasterio
>>> rasterio.__version__
'1.1.5'
>>> rasterio.gdal_version()
'3.0.4'

Thanks

..Tom

Per https://gdal.org/user/virtual_file_systems.html#drivers-supporting-virtual-file-systems and confirmed by Even R, GDAL's NetCDF driver cannot write to /vsi*. Perhaps a workaround can be to drop to a tempfile approach when writing NetCDF.

Thanks again for the clarifications.