The active page is now the  new moles website

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, Phil.Trans.Roy.Soc.A., to appear.
  • 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 (currently in DIF format, but soon to be ISO19115/19139 compliant).

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).

Current Objectives

The main objectives within NDG3 are to

  1. Improve the code and support for MOLES V1.3 for those sites with MOLES 1.3 data
    • MOLES V1 was developed during NDG and NDG2, and deployed in NDG2. 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.
      • Better support for BODC MOLES documents is anticipated under the NDG-MSI in the MILK stack.
  2. Complete the development of the MOLES V2 information model (and supporting code), and deploy at BADC and NEODC.
    • 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 which we hope to be more standards compliant. It is being deployed at  CEDA (BADC and NEODC) using their own internal funding.
      • It will be integrated into MILK in the NDG-MSI.
  3. The development of the MOLES V3 information model.
    • Community workshops and information modelling will take MOLES1 and MOLES2 and develop a new information model which is more complementary with other key existing standards (including ISO19115 and Observations and Measurements).
      • UML and documentation will be developed in the NDG-MSI.

Useful MOLES pages


  • Load a collection of MOLES documents into eXist - sample code.

Current tickets (some of which may be historical) are:

MOLES - Video and Audio

NDG3: Capability, Discovery, Vocab, Software, MOLES, Security, Community, Roadmap, Management