Data: To get started, organize your data into the fewest logical units, e.g., data tables. Ideally, many tables of the same structure and content should be compiled into a single table. Spatial data files (e.g. shape files) of a common theme or scope should be zipped up in their respective folders.
Metadata: Essential metadata is the who, what, when, where, why and how – which will be placed in structured metadata. “Who, what, when, where” are essential documentation. “Why and how” aid in understanding the data and are generally described in text metadata fields.
You will be producing a “data package”, i.e., the published unit of data and metadata together. Data repositories that are designed for both archive and delivery (like EDI’s) have these features, which you should keep in mind
- metadata and data immutability, so that data are trustworthy (e.g., to repeat an analysis),
- data package versioning, with earlier revisions still available,
- DOI assigned for each new package or revision, so that data can be cited exactly
Below are guidelines for grouping data into packages. The main features to consider are
- similarity and relatedness of methods and observations, and
- temporal nature, i.e., whether sampling is completed or is planned to be ongoing
Groups of data units with fixed start/end dates: Often these are packaged together with one metadata file. A primary data table could be accompanied by a table of sampling sites or taxonomic information that contains more material than can be fit into structured metadata.
- Large sampling campaign where many parameters are measured (and possibly independent): These may benefit from being broken into several packages, all accompanied by some of the same metadata and each with some unique metadata.
Both patterns (one package or multiple) are valid. In addition to considering your own management constraints and circumstances, be aware of your data’s potential future uses, and whether certain data entities naturally belong together.
Ongoing time-series observations (instrumented or not): Remember that all data packages have static data entities, and so in the case of ongoing time-series, these are “snapshots” at points in time.
- continuous: all observations are groupled into a single unit (table), with plans to add data by revising the same package and updating metadata.
- non-continuous: a new packages is created for each logical unit (e.g., a summer sampling season), regardless of similarities or differences in methods.
There are advantages and disadvantages to both approaches.