Library visibility on the Web
-----------------------------

Introduction
~~~~~~~~~~~~

Evergreen follows a number of best practices to
make Library data integrate with the rest of the
Web.  Evergreen's public catalog pages are
designed so that search engines can easily extract
meaningful information about your library and
collections.  Evergreen is also preparing for an
eventual shift toward linked open bibliographic
data.

Catalog data in search engines
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Each record in the catalog is displayed to search
engines using http://schema.org[schema.org] microdata.

[IMPORTANT]
Make sure your system administrator has not added
a restrictive robots.txt file to your server.
These files restrict search engines, up to the
point of not allowing search engines to index your
site at all.

Details of the schema.org mapping
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 * Each item is listed as a
   http://schema.org/Offer[schema:Offer], which is
   the same category that an online bookseller might
   use to describe an item for sale.  These Offers
   are always listed with a price of $0.00.
 * Subject headings are exposed as
   http://schema.org/about[schema:about]
   properties.
 * Electronic resources are assigned a
   http://schema.org/url[schema:url]
   property, and any notes or link text
   are assigned a
   http://schema.org/description[schema:description]
   property.
 * Given a Library of Congress relator code for
   1xx and 7xx fields, Evergreen surfaces the URL
   for that relator code along with the
   http://schema.org/contributor[schema:contributor]
   property to give machines a better chance
   of understanding how the person or organization
   actually contributed to this work.
 * Linking out to related records:
   ** Given an LCCN (010 field), Evergreen links to
      the corresponding Library of Congress record
      using http://schema.org/sameAs[schema:sameAs].
   ** Given an OCLC number (035 field, subfield `a`
      beginning with `(OCoLC)`), Evergreen links to
      the corresponding WorldCat record using
      http://schema.org/sameAs[schema:sameAs].
   ** Given a URI (024 field, subfield 2 = `'uri'`),
      Evergreen links to the corresponding OCLC
      Work Entity record using
      http://schema.org/exampleOfWork[schema:exampleOfWork].


Viewing microdata
^^^^^^^^^^^^^^^^^
You can learn more about how Evergreen publicizes
these data by viewing them directly.  The 
http://linter.structured-data.org[structured data linter]
is a helpful tool for viewing microdata.

. Using your favorite Web browser, navigate to a
  record in your public catalog.
. Copy the URL that displays in your browser's
  address bar.
. Go to http://linter.structured-data.org
. Under the _Lint by URL_ tab, paste your URL
  into the text box.
. Click _Submit_

Other helpful features for search engines
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 * Titles of catalog pages follow a
   "Page title - Library name" pattern to provide
   specific titles in search engine results pages,
   browser bookmarks, and browser tabs.
 * Links that robots should not crawl, such as search
   result links, are marked with the
   https://support.google.com/webmasters/answer/96569?hl=en[@rel="nofollow"]
   property.
 * Catalog pages for record details and for library
   descriptions express a
   https://support.google.com/webmasters/answer/139066?hl=en[@rel="canonical"]
   link to simplify the number of variations of page
   URLs that could otherwise have been derived from
   different search parameters.
 * Catalog pages that do not exist return a proper
   404 "HTTP_NOT_FOUND" HTTP status code, and record
   detail pages for records that have been deleted
   now return a proper 410 "HTTP_GONE" HTTP status code.
 * Record detail and library pages include
   http://ogp.me/[Open Graph Protocol] markup.
 * Each library has its own page at
   _http://localhost/eg/opac/library/LIBRARY_SHORTNAME_
   that provides machine-readable hours and contact
   information.

SKOS support
~~~~~~~~~~~~

Some vocabularies used (or which could be used) for
stock record attributes and coded value maps in Evergreen
are published on the web using SKOS. The record
attributes system can now associate Linked Data URIs
with specific attribute values. In particular, seed data
supplying URIs for the RDA Content Type, Media Type, and
Carrier Type has been added.

This is an experimental, "under-the-hood" feature that
will be built upon in subsequent releases.