59e04ae071
cloud using a variant of the Zarr protocol and storage format. This enhancement is generically referred to as "NCZarr". The data model supported by NCZarr is netcdf-4 minus the user-defined types and the String type. In this sense it is similar to the CDF-5 data model. More detailed information about enabling and using NCZarr is described in the document NUG/nczarr.md and in a [Unidata Developer's blog entry](https://www.unidata.ucar.edu/blogs/developer/en/entry/overview-of-zarr-support-in). WARNING: this code has had limited testing, so do use this version for production work. Also, performance improvements are ongoing. Note especially the following platform matrix of successful tests: Platform | Build System | S3 support ------------------------------------ Linux+gcc | Automake | yes Linux+gcc | CMake | yes Visual Studio | CMake | no Additionally, and as a consequence of the addition of NCZarr, major changes have been made to the Filter API. NOTE: NCZarr does not yet support filters, but these changes are enablers for that support in the future. Note that it is possible (probable?) that there will be some accidental reversions if the changes here did not correctly mimic the existing filter testing. In any case, previously filter ids and parameters were of type unsigned int. In order to support the more general zarr filter model, this was all converted to char*. The old HDF5-specific, unsigned int operations are still supported but they are wrappers around the new, char* based nc_filterx_XXX functions. This entailed at least the following changes: 1. Added the files libdispatch/dfilterx.c and include/ncfilter.h 2. Some filterx utilities have been moved to libdispatch/daux.c 3. A new entry, "filter_actions" was added to the NCDispatch table and the version bumped. 4. An overly complex set of structs was created to support funnelling all of the filterx operations thru a single dispatch "filter_actions" entry. 5. Move common code to from libhdf5 to libsrc4 so that it is accessible to nczarr. Changes directly related to Zarr: 1. Modified CMakeList.txt and configure.ac to support both C and C++ -- this is in support of S3 support via the awd-sdk libraries. 2. Define a size64_t type to support nczarr. 3. More reworking of libdispatch/dinfermodel.c to support zarr and to regularize the structure of the fragments section of a URL. Changes not directly related to Zarr: 1. Make client-side filter registration be conditional, with default off. 2. Hack include/nc4internal.h to make some flags added by Ed be unique: e.g. NC_CREAT, NC_INDEF, etc. 3. cleanup include/nchttp.h and libdispatch/dhttp.c. 4. Misc. changes to support compiling under Visual Studio including: * Better testing under windows for dirent.h and opendir and closedir. 5. Misc. changes to the oc2 code to support various libcurl CURLOPT flags and to centralize error reporting. 6. By default, suppress the vlen tests that have unfixed memory leaks; add option to enable them. 7. Make part of the nc_test/test_byterange.sh test be contingent on remotetest.unidata.ucar.edu being accessible. Changes Left TO-DO: 1. fix provenance code, it is too HDF5 specific. |
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|---|---|---|
| .github | ||
| cmake | ||
| conda.recipe | ||
| ctest_scripts | ||
| dap4_test | ||
| debug | ||
| docs | ||
| examples | ||
| h5_test | ||
| hdf4_test | ||
| include | ||
| libdap2 | ||
| libdap4 | ||
| libdispatch | ||
| libhdf4 | ||
| libhdf5 | ||
| liblib | ||
| libnczarr | ||
| libsrc | ||
| libsrc4 | ||
| libsrcp | ||
| nc_perf | ||
| nc_test | ||
| nc_test4 | ||
| ncdap_test | ||
| ncdump | ||
| ncgen | ||
| ncgen3 | ||
| nctest | ||
| nczarr_test | ||
| NUG | ||
| oc2 | ||
| plugins | ||
| unit_test | ||
| .gitignore | ||
| .travis.yml | ||
| acinclude.m4 | ||
| appveyor.yml | ||
| bootstrap | ||
| cmake_uninstall.cmake.in | ||
| CMakeInstallation.cmake | ||
| CMakeLists.txt | ||
| COMPILE.cmake.txt | ||
| config.h.cmake.in | ||
| config.h.cmake.in.old-works | ||
| configure.ac | ||
| COPYRIGHT | ||
| CTestConfig.cmake.in | ||
| CTestCustom.cmake | ||
| dods.m4 | ||
| FixBundle.cmake.in | ||
| INSTALL.md | ||
| lib_flags.am | ||
| libnetcdf.settings.in | ||
| Makefile.am | ||
| mclean | ||
| nc-config.cmake.in | ||
| nc-config.in | ||
| netcdf.pc.in | ||
| netCDFConfig.cmake.in | ||
| PostInstall.cmake | ||
| postinstall.sh.in | ||
| README.md | ||
| RELEASE_NOTES.md | ||
| test_common.in | ||
| test_prog.c | ||
| test-driver-verbose | ||
| wjna | ||
Unidata NetCDF
About
The Unidata network Common Data Form (netCDF) is an interface for scientific data access and a freely-distributed software library that provides an implementation of the interface. The netCDF library also defines a machine-independent format for representing scientific data. Together, the interface, library, and format support the creation, access, and sharing of scientific data. The current netCDF software provides C interfaces for applications and data. Separate software distributions available from Unidata provide Java, Fortran, Python, and C++ interfaces. They have been tested on various common platforms.
Properties
NetCDF files are self-describing, network-transparent, directly
accessible, and extendible. Self-describing means that a netCDF file
includes information about the data it contains. Network-transparent
means that a netCDF file is represented in a form that can be accessed
by computers with different ways of storing integers, characters, and
floating-point numbers. Direct-access means that a small subset of a
large dataset may be accessed efficiently, without first reading through
all the preceding data. Extendible means that data can be appended to
a netCDF dataset without copying it or redefining its structure.
Use
NetCDF is useful for supporting access to diverse kinds of scientific data in heterogeneous networking environments and for writing application software that does not depend on application-specific formats. For information about a variety of analysis and display packages that have been developed to analyze and display data in netCDF form, see
More information
For more information about netCDF, see
Latest releases
You can obtain a copy of the latest released version of netCDF software for various languages:
Copyright
Copyright and licensing information can be found here, as well as in the COPYRIGHT file accompanying the software
Installation
To install the netCDF-C software, please see the file INSTALL in the netCDF-C distribution, or the (usually more up-to-date) document:
Documentation
A language-independent User's Guide for netCDF, and some other language-specific user-level documents are available from:
- Language-independent User's Guide
- NetCDF-C Tutorial
- Fortran-90 User's Guide
- Fortran-77 User's Guide
- netCDF-Java/Common Data Model library
- netCDF4-python
A mailing list, netcdfgroup@unidata.ucar.edu, exists for discussion of the netCDF interface and announcements about netCDF bugs, fixes, and enhancements. For information about how to subscribe, see the URL
Feedback
We appreciate feedback from users of this package. Please send comments, suggestions, and bug reports to support-netcdf@unidata.ucar.edu.