Metadata Objects for Linking Environmental Sciences

What are MOLES?

The Metadata Objects for LInking Environmental Sciences are documents which either provide descriptions of some key features of environmental data and their context or provide links to those descriptions. The key features which MOLES documents are designed to address are

  • Providing the context required to choose between two otherwise similar data objects (i.e. between two datasets measuring and/or simulating the same properties at the same time/location/resolution). This is to be achieved by encapsulating the descriptions themselves within the MOLES documents OR by providing links to documents constructed using other semantics (e.g. SensorML or Metafor documents) OR by including documents in those other semantics as "payload documents" within MOLES. In the latter two modes we think of MOLES as a "coathanger" to browse metadata. The importance of browse metadata is described in  Lawrence 2009.
  • Providing a method of semantically linking datasets, activities etc between institutions, so that not only are the links visible, but their meanings are visible. A concrete example of this application would be to provide a methodology for cross-institution projects to have metadata (and data) held locally in the institutions, but all institutions offering MOLES documents which essentially make the "project" website visible at all institutions.
  • Elucidating the relationships between activities, data, instruments, algorithms etc in a semantically consistent and standards compliant manner.

By construction, MOLES is intended to be a superset of so-called "discovery" metadata, and so MOLES documents can be parsed to extract discovery metadata documents.

MOLES is not intended to be the primary metadata storage mechanism at any institution, but it can be (and it is being used in this mode at  CEDA).

An introduction to the MOLES concepts appears here.

Go here to get started with MOLES information modelling.

See the meetings page for meeting details.

Other data modelling activities will be linked or described on the OtherApproaches page.

MOLES Intellectual Property

  • The MOLES specifications are in the public domain, anyone is free to use MOLES as and where they like. Anyone interested in the ongoing development of MOLES is welcome to join the MOLES  mailing list. If you want to actively contribute, you can sign up for write access to this trac instance. Currently the method to join this is
    •  Register with the badc (if you haven't already), and
    •  contact badc via the email address and ask for MOLES trac access!
  • Software to support MOLES forms part of a number of other projects, all of which have liberal (open source) licenses. Details of those projects will appear here soon.

MOLES Versions

  • MOLES V1 was developed during NDG and NDG2, and deployed in NDG2 at the Plymouth Marine Laboratory, British Atmospheric and Oceanographic Data Centres, NERC Earth Observation Data Centre and the Southampton Oceanography Centre (mostly as prototype servers). A number of major issues were identified with the structure and format of the XML schema which defined it. MOLES V1 is still deployed and supported to an extent, but during 2009/2010 we want to migrate any V1 instances to V2.
  •  MOLES V2 has been developed in response to the many things we obviously did wrong in the construction of MOLES 1, and as a prototype for MOLES V3. It is being deployed at  CEDA.
  • [MOLES V3] is under active development, with development goals being more standards compliance, easier deployment and use, and wider domain applicability.

Project Status

(Last updated Feb 14, 2011)

The establishment of the MOLES concepts, and initial implementations (V1) were funded by the  NERC DataGrid project. Work then progressed under two funding lines:

  • The so-called NDG3 project funded a) upgrading the MOLES information model to be more standards compliant (V3.2), and b) developing a plan for the integration of MOLES within the wider NERC community. That plan culminated in the details discussed in the November workshop.
  • The  BADC has funded the development and implementation of MOLES V2.0 as a persistence format at  CEDA.

Ongoing work is currently funded for the meantime within the resources of the project contributors. Significant development is expected in 2011, with V3.4 being finalised in February, to be immediately followed by V3.5. The primary difference between V3.4 and V3.5 will be that 3.4 will not handle computational objects.

Activity on the project can be followed by examining the timeline (above), and by looking at the meetings page. (Note that not all meetings result in an addition there - some meetings are only recorded by annotations to tickets.)

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