Resource Availability
The availability of a resource is expressed using the following constrained vocabulary:
- online (free)
- online (portal)
- online (login)
- unpublished (digital)
- published (digital)
- published
- unpublished
Introduction
Media resources like images or sounds are typically available in different quality levels (e. g., high-resolution, web-optimized, or different thumbnail sizes), under different URIs. The availability of resources at different quality levels may differ. The Best Quality may be available only after login, or even offline, lower qualities may be online and free. We use a “denormalized” structure, i.e. for each quality level fields for URI, Availability, Size, Image Width, Image Height, Duration, Format, License, etc. exist.
For online digital resources we use URLs (Universal Resource Locators, i. e. the addresses one would type into the address field of a web browser). However, a resource may be available only after browsing (link points to a portal), after login (URL access is interrupted by login procedure) or it may be offline (digital or non-digital, published or not). The following table explains the possible values for resource availability:
| Availability Value | Description | URI examples |
|---|---|---|
| online (free) | This is a publicly visible URI, where the resource is immediately accessible . | http://server.it/path/file123.jpg |
| online (portal) | This is a publicly visible URI, where the resource is accessible only after browsing or searching by a human (i.e. the URL is only a portal) | http://server.it/path/file123.jpg |
| online (login) | This is a URL that is not publicly accessible, because authorization (e.g. login or sign-in using username, password, token, etc.) is required | http://server.it/path/file123.jpg |
| unpublished (digital) | Local digital files are indicated by this value or prefix (compare http://en.wikipedia.org/wiki/File:URI). Use “file://” as a value if you want to keep the file location private, use it as a prefix if you want to share local file locations (e. g to simplify communication). file:// may also refer to unpublished local CDs. | file://Oudemans/Storage/Fungi/234.jpg |
| published (digital) | Use as value or prefix for published digital content that is not available online (especially published CDs). Please try to create a valid URN for these, preferably based on ISBN codes, as shown in the example. See also the field “Published Source”, which may repeat some of this information in free form text and greater detail. | urn:isbn:234-23-23444-X |
| published | Use this for published, non-digital content. See also the field “Published Source”. | urn:isbn:234-23-23444-X |
| unpublished | Use this for unpublished, non-digital content like printed photos, slides, analogue tapes, etc. Use information like author, year, title, project, etc. to create a unique descriptive string after the “urn:unpublished:” | urn:unpublished:CollectionMatt_(old) |
Note to Key to Nature data providers: The first survey flat-table exchange standard used to use URI prefixes. This is no longer supported, the Availability field must be used instead.
