Difference between revisions of "WCS NetCDF Development"

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Back to [[WCS_Access_to_netCDF_Files]]
 
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'''Web Coverage Service Access from NetCDF Files.'''
 
 
 
The goal is to provide you an easy way to publish your data in NetCDF format.
 
 
 
The cross-platform toolkit from data to Web Service contains:
 
 
 
* Checking the CF compatibility of your data.
 
* Creating CF compatible NetCDF files from your data.
 
* Setting up a Web Coverage Service directly from your files with no extra configuration.
 
 
 
Below are sections and descriptions to all the tools we provide. Feel free to participate!
 
 
 
== Cross Platform Python-NetCDF Library ==
 
 
 
The most feature-rich library to access NetCDF files via python is PyNIO. Unfortunately it is unix-only. That's why '''nc3''' was created. The two purposes of '''nc3''' are:
 
 
 
* Provide simple read and write access to NetCDF files.
 
* WCS query: Extract a subcube from a NetCDF.
 
 
 
This is supposed to be a small library. The subcube query is supposed to be fast, everything else is supposed to be simple. If you do a lot of data processing using NetCDF or python, we recommend PyNIO.
 
 
 
== NetCDF Markup Language: NCML ==
 
 
 
Creating a NetCDF file via plain API is difficult, NCML allows you to describe dimensions, variables and attributes in one xml document. This simplifies creating an empty NetCDF file a great deal.
 
 
 
Example NCML use:
 
 
 
(enter sample URL here)
 
 
 
== CF-1.x Convention ==
 
 
 
It's not enough to have NetCDF as format, you also need to standardize the attribute names, how to store dimensions etc. To make it easy to create CF-1.x compatible files, we provide a python library '''cf1'''.
 
 
 
The main page for CF-1.4 documentation: http://cf-pcmdi.llnl.gov/
 
 
 
(enter our sample project here)
 
 
 
== Getting the binaries for Windows ==
 
 
 
Please follow the installation instructions in [[WCS_Wrapper_Installation_WindowsOP| Windows]] or [[WCS_Wrapper_Installation_LinuxOP| Linux]]. You have to install '''python 2.6''' and three libraries. Windows is up to date, Linux is being updated.
 
 
 
This is enough for those who just want to create NetCDF-CF files and serve them as WCS. The python code is still delivered as source, so you can change it, but if you do please get the source code the proper way. Without darcs repository, you will net be able to submit your improvements to common use.
 
 
 
== Getting The Source for Windows ==
 
 
 
We're using [http://www.darcs.net/ darcs]. It is a very flexible DVCS: Distributed Version Control System. The one big page documentation is [http://www.darcs.net/manual/bigpage.html here].
 
 
 
Download it from here for [http://wiki.darcs.net/Binaries#for-windows-without-cygwin Windows 2.2.1] and [http://wiki.darcs.net/Binaries Other Operating Systems].
 
 
 
If you are a Windows user we recommend integrated GUI [http://datafed.net/darcs/ TortoiseDarcs].
 
 
 
Once you have darcs installed, issue command:
 
 
 
<html>
 
<pre>
 
darcs get http://webapps.datafed.net/nest/OWS
 
</pre>
 
</html>
 
 
 
This will create directory '''OWS''' into your current folder. For windows, we recommend C:\. You need to have write rights in your current folder for temporary files.
 
 
 
Now you are free to edit any file.
 
 
 
* OWS stands for OpenGeoSpatial Web Services. Most popular is WMS, Web Map Service. This project may later include other web services besides WCS as well.
 
 
 
== Currently Existing Darcs Repositories ==
 
 
 
[http://webapps.datafed.net/nest/OWS Datafed]
 
 
 
[http://htap.icg.fz-juelich.de/darcs/OWS Juelich]
 
 
 
== Currently Live WCS Servers ==
 
 
 
List of installed WCS servers here.
 
 
 
== Existing Features of WCS ==
 
 
 
* describe kinds of dimensions
 
* kinds of lat/lon filters
 
* kinds of time filters
 
* [http://en.wikipedia.org/wiki/ISO_8601 ISO time format]
 
 
 
== Feature Requests of WCS ==
 
 
 
* Support both -180..180 and 0..360 coordinate systems.
 
* Allow queries across longitude, from 179..-179 or 359..1 as a two-degree query, as the spec says.
 
* Support bounds variables, especially for time dimension.
 
* Support WCS 1.0.0, it has filter for elevation/depth dimension, as well as WIDTH,HEIGHT and DEPTH sampling filters.
 
* Support NetCDF 4 and 2GB Files.
 
* Improve the admin tool to give better error messages and progress messages.
 
* Watch for [http://www.opengeospatial.org/projects/groups/wcs1.2swg WCS 1.2]
 
 
 
== Update Log ==
 
 
 
2009-07-15: Updated the Windows runtime and installation instructions.
 
 
 
2009-07-08: Started this page.
 
 
 
2009-07-02: First External darcs repository for OWS at Juelich.
 
 
 
2009-06-04: After being used for some datasets at Datafed, we get the first external developer, M. Decker, to contribute to the source code. He adds non-ascii character support.
 
 
 
2007-11-21: First Real Dataset online.
 
 
 
2007-11-12: First Linux port.
 
 
 
2007-10-22: Development starts for Windows.
 
 
 
== Web Resource Pages Tagged netCDF ==
 
* Recently tagged pages '''netCDF''': http://delicious.com/tag/netCDF
 
* Popular pages tagged '''netCDF''': http://delicious.com/popular/netCDF
 
* Pages tagged '''netCDF+API''': http://delicious.com/tag/netCDF+API
 
* Pages tagged '''netcdf+CF''': http://delicious.com/tag/netCDF+CF
 
 
 
----
 
* Russ Rew's (Unidata Developer) pages tagged netCDF: http://delicious.com/RussRew/netCDF
 
 
 
 
 
 
 
<rss>http://delicious.com/popular/netCDF</rss>
 

Latest revision as of 11:34, December 15, 2010