Use Case 16: Preview Granule (metadata driven)
Use Case EIE16: Preview Granule (Metadata driven)
ESIP Earth Information Exchange
Version 1.0 draft
Prepared by Karl Benedict
Earth Data Analysis Center, University of New Mexico
November 22, 2005
- 1 1.Use Case Identification
- 2 2.Use Case Definition
- 2.1 2.1.Actors
- 2.2 2.2.Preconditions
- 2.3 2.3.Postconditions
- 2.4 2.4.Normal Flow
- 2.5 2.5.Alternative Flows
- 2.6 2.6.Exceptions
- 2.7 2.7.Extension Points
- 2.8 2.8.Priority
- 2.9 2.9.Frequency of Use
- 2.10 2.10.Business Rules
- 2.11 2.11.Special Requirements
- 2.12 2.12.Assumptions
- 2.13 2.13.Notes and Issues
1.Use Case Identification
1.1.Use Case Number
1.2.Use Case Name
Provide a standard preview of a data granule as referenced by an element in the granule metadata.
2.Use Case Definition
This use case represents a need to provide system users a preview of a data granule that they are considering for use or download. This preview would be encoded into the metadata for the granule, and be accessible via a simple URL. The preview may be generated by a service or represented by a static image file (browser supported) accessible via the URL, but access should be via a simple URL request.
- 1.User has been presented with a list of granules (Use case EIE09)
- 2.If the metadata for a listed granule provides a preview URL, a link to that URL will be included in the granule listing.
- 1.The user is provided with a preview image
- EIE16.0.1) When a list of granules is generated as a result of a granule listing, available preview URLs are read from the metadata records
- EIE16.0.2) Preview links are added to the listing of granules, as available.
Metadata do not contain preview URLs:
- EIE16.1.1) Granules lacking preview URLs are listed without corresponding links.
Preview file returned by URL is not a valid image file. Display an error message to the user and log the error.
2.9.Frequency of Use
Invoked multiple times per session
URLs corresponding with preview images must return a valid image file.
2.13.Notes and Issues
Recommendations regarding performance requirements and file sizes should be produced to provide a reasonable system response when providing preview images. Computationally intensive 'live' previews might be discouraged.