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>From: Lihua Li <address@hidden> >Organization: University of Massachussetts >Keywords: 199408222035.AA12492 netcdf Lihua, > I'd like to open some netCDF files and access data from them,but I >have no idea about how to do that. Would you please introduce me some >helpful materials and sample programs and tell me where I can obtain them. >Thank you very much! netCDF is a file format for holding data in a platform independant manner. I have appended the netCDF README file for your information. There are some sample files available on anonymous ftp to unidata.ucar.edu in the pub/netcdf/sample_data directory. Theses files are binary in nature, so remember to set your ftp transfer to binary mode. In order to look at these files (that are binary in nature), you need to create software to look at them. We provide a "library" that can be built on a number of platforms that allow you to create programs that will be able to read netCDF files. The UNIX version of the distribution (on our ftp area) has a utility called "ncdump" that allows you to view the contents of a netCDF file in ascii form. I suggest you look over the readme, then look around our ftp area for netcdf. You could then down load netcdf (netcdf.tar.Z), uncompress and untar it, then build it on a system there. We use the netCDF format to hold various weather and related data. Mike Wright Unidata netCDF Version 2.3.2 June 1993 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 common C and FORTRAN interfaces for applications and data. It has been tested on various common platforms, including several versions of UNIX, VMS, MSDOS, and OS/2. 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. 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. A variety of analysis and display packages have been developed to analyze and display data in netCDF form. You can obtain a copy of the latest version of netCDF software using anonymous FTP from host: unidata.ucar.edu file: pub/netcdf/netcdf.tar.Z Included in this distribution are: the C source for the netCDF data access library, sources for the FORTRAN jacket library for various systems, documentation for the netCDF library and utilities in the form of a netCDF User's Guide, source for the netCDF utilities ncdump and ncgen, a directory of test programs to verify the correct implementation of the netCDF library in new environments, and a directory of XDR (eXternal Data Representation) source code for environments that do not support XDR. Other files available for anonymous FTP from the pub/netcdf/ directory of unidata.ucar.edu include README general information about netCDF FAQ Frequently Asked Questions (with answers) about netCDF. utilities.txt a list of software packages currently available or under development for manipulating and displaying netCDF data guide.ps.Z a compressed PostScript file of the NetCDF User's Guide. This is included in the netcdf.tar.Z distribution, so you don't need both. ncprogs.ps a draft PostScript document describing an initial set of netCDF operator and utility programs under development ncprogs.txt an ASCII version of ncprogs.ps conventions.info a draft document of some proposed netCDF conventions cdl/ a directory containing some examples of CDL files (an ASCII representation for netCDF files). msdos/ a directory containing executables and binaries for netCDF under MSDOS 5.0. These can also be built from the sources in netcdf.tar.Z, if you have the necessary Microsoft compilers. mac/ a directory containing notes and Macintosh MPW makefiles for porting netCDF to an Apple Macintosh. These were contributed by Chuck Denham, U.S. Geological Survey. A mailing list, address@hidden, exists for discussion of the netCDF interface and announcements about netCDF bugs, fixes, and enhancements. To subscribe, send a request to address@hidden An archive of past postings to the netcdfgroup mailing list is available for anonymous FTP from the file mail-archives/netcdfgroup of unidata.ucar.edu. A recent paper that provides a good introduction to the use of netCDF appeared in Jenter, H. L. and R. P. Signell, 1992. "NetCDF: A Freely-Available Software-Solution to Data-Access Problems for Numerical Modelers". Proceedings of the American Society of Civil Engineers Conference on Estuarine and Coastal Modeling. Tampa, Florida. This paper is available via anonymous FTP from host: crusty.er.usgs.gov file: pub/netcdf.asce.ps Specific questions about netCDF that are not of interest to the netcdfgroup mailing list may be sent to address@hidden.