XMP Schema for Rail Photos - v1.0

Introduction

This page describes a custom XMP metadata schema I have developed and use for cataloguing my railway photos, and contains the technical information you will require in order to view or use this metadata and integrate it into desktop searching tools. XMP is Adobe's eXtensible Metadata Platform which provides a framework for embedded document metadata and is used by Photoshop and other Adobe applications for management of metadata embedded into image files such as JPEGs and TIFFs. XMP is an XML format based on the public Resource Description Framework (RDF) standard.

I now use this technology for incorporating metadata into my photographs - all signal photos added to this site since 13/8/06 include XMP metadata using this schema in addition to the standard ones.

This page contains the following information:

the schema's URI, preferred XML namespace prefix and GUID;
the specification of the schema's properties and their vocabularies;
some further explanatory notes; and
additional resources and references, including a Photoshop custom metadata panel for this schema and some configuration files to help incorporate it into standard desktop searching tools on Windows using IFilterShop's XMP IFilter desktop file search plugin v2.0.

Schema namespace URI

http://www.roscalen.com/RailwayPhotos/1.0/

Preferred schema namespace prefix

RailPhoto

GUID

I have allocated this schema a GUID of {32D05854-40C7-44DB-B41E-1443376DE391} for use with IFilterShop's XMP IFilter desktop file search plugin v2.0.

Properties

Property	Value Type	Category	Description
signalboxes	bag Text	External	An unordered array listing the signalbox(es) appearing, or controlling the signals appearing, in the photo.
line	Text	External	The line on which the photo was taken.
companies	bag Text	External	An unordered array listing the companies who owned the line(s) shown in the photo, eg Great Western Railway, London & North Western Railway, etc. Multiple entries should be made for joint lines.
category	closed Choice	External	Category of photo (see below).
importance	closed Choice	External	Importance of photo (see below).
grade	Text	External	A quality grading assigned to the photo. I use an A+ to E- system, but it is not obligatory to follow that convention.
sequence	Integer	External	The sequence number of the photo within the full collection. I have assigned sequence numbers to my slide collection, but no longer do so for newly taken digital photos.
item	Integer	External	The sequence number of the photo within its category. I have assigned category sequence numbers to my slide collection, but no longer do so for newly taken digital photos.
substitution	Boolean	External	If set to true this property indicates that the photo in question is a later substitute for an earlier one of the same subject which was of poorer quality.
epoch	Text	External	An unformatted string into which the approximate date when the photo was taken, eg "May 73", can be entered in cases where the exact date is not known. Labelled as When taken: on the custom Photoshop metadata panel provided below. Where I do have the exact date available, I store this in the IPTC Core/Photoshop DateCreated property and leave this property unset.
film	Integer	External	The sequence number of the film on which the photo was taken. I assigned each slide film I used a sequence number, but this property is clearly not relevant to digital photos.

Category code vocabulary

Value	Description
1 - 4DD train	The class-4DD double-decker train that used to run on the BR Southern Region
2 - Birmingham New St Signal	The unique colour-light signals that used to be at Birmingham New Street.
3 - Signalling	Signalling generally.
4 - Cadburys	Cadbury's private locos and rolling stock used at their former sidings at Bournville.
5 - General Trains	Other, non-signalling-related rail photos.
6 - Train Interiors	Photos of train interiors.
7 - Model Railways	Photos of model railways.
8 - Trams	Photos of trams and tramways.
	This property may also be left unset.

Importance level vocabulary

Value	Description
1 - High	Of wide interest.
2 - Normal	Important for reference purposes.
3 - Low	Of marginal importance.
	This property may also be left unset.

Notes

This schema is designed to be used in conjunction with the standard Photoshop, Dublin Core, and IPTC Core schemas (it is also complementary to EXIF). The custom panel also includes fields linked to the following standard properties from those schemas:
- dc:title
- Iptc4xmpCore:Location
- photoshop:City (labelled as Town: on the panel to reflect UK practice)
- photoshop:State (labelled as County: on the panel to reflect UK practice)
- photoshop:Country (populated as England, Wales or Scotland in my British photos)
- Iptc4xmpCore:CountryCode (ISO country code, eg GBR)
- photoshop:DateCreated
The category code vocabulary may be extended in future versions. The current list is a legacy classification based on the system I used for cataloguing my slide collection. Category codes are numbered because the numbers were what I annotated my slide mounts with.

Resources

Custom metadata panel for Adobe Photoshop CS2. Saving this file in an appropriate directory will allow you to view metadata from this schema using the Photoshop File Info dialogue or the metadata pane in Bridge. The appropriate directories for Windows users are normally C:\Program Files\Common Files\Adobe\XMP\Custom File Info Panels or C:\Documents and Settings\{user}\Application Data\Adobe\XMP\Custom File Info Panels; for Macintosh users, {root volume}/Library/Application Support/Adobe/XMP/Custom File Info Panels or {home directory}/Library/Application/Adobe/XMP/Custom File Info Panels. Subsitute the appropriate actual strings for the italicised portions in braces. In either case, saving in the first directory makes the panel available to all users of the machine, while the second directory is local to the current user.
a schema configuration file for use with IFilterShop's XMP IFilter plugin v2.0, which now supports custom XMP schemas thus allowing metadata values to be used in Windows file searches. This only includes some of the custom properties, so you can customise it if you wish to include others or remove some of the ones I use - see the Readme file provided with the XMP IFilter for further information and instructions.
a Windows regedit script to create the registry keys required to register this schema with the XMP IFilter. This file assumes you have installed the above schema configuration file in the directory C:\Documents and Settings\All Users\Application Data\RailwayPhotos - if not, you will need to edit the last line of this script accordingly before executing it.
the XMP SDK on Adobe's site contains important reference information including the XMP Specification;
Adobe's site also contains further information on developing custom panels for Photoshop and other Adobe applications; and
for information about RDF, visit www.w3.org/RDF/.