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mjgiarlo edited this page Sep 14, 2012 · 12 revisions

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Digital Image Library (Northwestern University Library)

Model and tests can be found here:

https://gist.github.com/3700575

Description

The Multiresimage model is used to represent an image object. The image itself is an external datastream retrieved by using Fedora disseminators to translate requests to our Aware Image Server. We have an archival version of the image (generally a TIFF file), as well as the display version (JPEG2000).

Relationships

belongs_to :admin_policy, :class_name=> "AdminPolicy", :property=>:is_governed_by

Each object belongs to AdminPolicy object ("is_governed_by"). This helps us enforce authorization to images by having each object subscribe to a policy object.

has_and_belongs_to_many :collections, :class_name=> "DILCollection", :property=> :is_member_of

Each image can belong to many ("is_member_of") user-generated Collections. Each user-generated Collection can have many images.

has_and_belongs_to_many :vraworks, :class_name => "Vrawork", :property => :is_image_of

Each image can belong to ("is_image_of") many VRA work objects. Each VRA Work object can have many images.

Datastreams

VRA: For the descriptive metadata about the image. See http://www.loc.gov/standards/vracore/schemas.html

DELIV-OPS: Uses the SVG schema to encode jp2 image path, size, crop, and rotation.

ARCHV-TECHMD: Technical metadata for the archival image.

ARCHV-EXIF: EXIF metadata for the archival image.

DELIV-TECHMD: Technical metadata for the JPEG2000 image.

ARCHV-IMG: External datastream that points to the archival image (served by web server)

DELIV-IMG: External datastream that points to the archival image (served by web server)

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