EML Beta6 to EML2 Converter

[Dan Higgins]

Hi All,

    I just thought that I would let you know that XSLT stylesheets to 
convert eml-beta6 to eml2 now are available. As indicated below, these 
are primarily for use with morpho, which currently produces beta6 
packages. The stylesheets are available in the eml package on cvs 
(cvs.ecoinformatics.org) in the 'eml/lib/beta6toeml2' directory or the 
transformation is now available as an export function in the version of 
Morpho at the head of the morpho CVS directory. (A formally released 
installer version should be available shortly.)

    Comments, questions, corrections, bug reports are all wecome.

Dan Higgins

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Mar 26, 2003
Exporting EML2 documents from Morpho

Morpho currently uses EMLBeta6 for modules in the packages it creates. 
Because there are a number of existing data packages in this format, the 
ability to export those packages to the newer EML2 format has been added 
to Morpho. Beta6 packages are made up of a number of distinct files 
(modules) linked by the 'triples' in the dataset module. The 'Export to 
EML2' function in the current version of Morpho (i.e. the version at the 
head of the CVS repository) combines these modules into a single EML2 
document.

To create an EML2 document, select the 'Export..." menu item. A dialog 
with three export functions appears - one exports a package to a local 
directory, one to a zip file, and the last creates an eml2 type document 
from an existing Morpho datapackage. Note that only metadata is placed 
in the exported EML2 document. All data files are referenced through the 
'distribution/online/url' element with a URL which downloads the data 
from a Metacat server.

The 'Export to EML2' does have some limitations. Currently 'software' 
and top-level 'citation' modules are not handled (although there are no 
known packages with these top level modules). Also, certain EML2 
elements such as the measurementScale elements of 'nominal', 'ordinal', 
'interval', and 'ratio' do not exist in Beta6, so the values chosen are 
somewhat arbitrary. In the case of the existing transformation, all 
string attributes are set to 'nominal', there are no 'ordinal' values, 
and all numeric attributes are set to 'ratio' or 'interval' depending on 
whether negative values are included in the range. Also, any units that 
cannot be located in the units-dictionary are converted to 'customUnits' 
and information needs to be added to the 'additionalMetadata' element by 
a human to describe these custom units.

I highly recommend running the resulting EML2 documents through the 
eml-validator (onlline at knb.ecoinformatics.org). For the most part, 
the resulting EML2 documents should be valid; however, the data in some 
valid Beta6 documents  will result in invalid EML2 documents since the 
XMLSchema requirements of EML2 are more severe than the DTD requirements 
of Beta6. Some human editing may thus be  required.

-- 
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Dan Higgins                                  higgins at nceas.ucsb.edu
http://www.nceas.ucsb.edu/    Ph: 805-892-2531
National Center for Ecological Analysis and Synthesis (NCEAS) 
735 State Street - Room 205
Santa Barbara, CA 93195
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