Initial conversion of spec to markdown.

Lots of reorganization remaining.

docs/_bookdown.yml

@@ -6,6 +6,9 @@ rmd_files: ["index.Rmd",
     "../README.md",
     "contributors.md",
     "eml-220info.md",
+    "ch1-spec-preface.md",
+    "ch2-spec-overview.md",
+    "ch3-spec-architecture.md",
     "release-notes.md",
     "about-this-book.md",
     "references.md"]

docs/ch1-spec-preface.md

@@ -0,0 +1,93 @@
+# Chapter 1. Preface
+
+## Introduction
+
+The Ecological Metadata Language (EML) is a metadata standard developed
+by the ecology discipline and for the ecology discipline. It is based on
+prior work done by the Ecological Society of America and associated
+efforts (Michener et al., 1997, Ecological Applications). EML is
+implemented as a series of XML document types that can by used in a
+modular and extensible manner to document ecological data. Each EML
+module is designed to describe one logical part of the total metadata
+that should be included with any ecological dataset.
+
+## Purpose Statement
+
+To provide the ecological community with an extensible, flexible,
+metadata standard for use in data analysis and archiving that will allow
+automated machine processing, searching and retrieval.
+
+## Features
+
+The architecture of EML was designed to serve the needs of the
+ecological community, and has benefitted from previous work in other
+related metadata languages. EML has adopted the strengths of many of
+these languages, but also addresses a number of short-comings that have
+proved to inhibit the automated processing and integration of dataset
+resources via their metadata.
+
+The following list represents some of the features of EML:
+
+-   Modularity: EML was designed as a collection of modules rather than
+    one large standard to facilitate future growth of the language in
+    both breadth and depth. By implementing EML with an extensible
+    architecture, groups may choose which of the core modules are
+    pertinent to describing their data, literature, and software
+    resources. Also, if EML falls short in a particular area, it may be
+    extended by creating a new module that describes the resource (e.g.
+    a detailed soils metadata profile that extends eml-dataset). The
+    intent is to provide a common set of core modules for information
+    exchange, but to allow for future customizations of the language
+    without the need of going through a lengthy \'approval\' process.
+
+-   Detailed Structure: EML strives to balance the tradeoff of too much
+    detail with enough detail to enable advanced services in terms of
+    processing data through the parsing of accompanied metadata.
+    Therefore, a driving question throughout the design was: \'Will this
+    particular piece of information be machine-processed, just human
+    readable, or both?\' Information was then broken down into more
+    highly structured elements when the answer involved machine
+    processing.
+
+-   Compatibility: EML adopts much of it\'s syntax from the other
+    metadata standards that have evolved from the expertise of groups in
+    other disciplines. Whenever possible, EML adopted entire trees of
+    information in order to facilitate conversion of EML documents into
+    other metadata languages. EML was designed with the following
+    standards in mind: Dublin Core Metadata Initiative, the Content
+    Standard for Digital Geospatial Metadata (CSDGM from the US
+    geological Survey\'s Federal Geographic Data Committee (FGDC)), the
+    Biological Profile of the CSDGM (from the National Biological
+    Information Infrastructure), the International Standards
+    Organization\'s Geographic Information Standard (ISO 19115), the ISO
+    8601 Date and Time Standard, the OpenGIS Consortiums\'s Geography
+    Markup Language (GML), the Scientific, Technical, and Medical Markup
+    Language (STMML), and the Extensible Scientific Interchange Language
+    (XSIL).
+
+-   Strong Typing: EML is implemented in an Extensible Markup Language
+    (XML) known as [XML Schema](http://www.w3.org/XML/Schema), which is
+    a language that defines the rules that govern the EML syntax. XML
+    Schema is an internet recommendation from the [World Wide Web
+    Consortium](http://www.w3.org), and so a metadata document that is
+    said to comply with the syntax of EML will structurally meet the
+    criteria defined in the XML Schema documents for EML. Over and above
+    the structure (what elements can be nested within others,
+    cardinality, etc.), XML Schema provides the ability to use strong
+    data typing within elements. This allows for finer validation of the
+    contents of the element, not just it\'s structure. For instance, an
+    element may be of type \'date\', and so the value that is inserted
+    in the field will be checked against XML Schema\'s definition of a
+    date. Traditionally, XML documents (including previous versions of
+    EML) have been validated against Document Type Definitions (DTDs),
+    which do not provide a means to employ strong validation on field
+    values through typing.
+
+-   There is a distinction between the content model (i.e. the concepts
+    behind the structure of a document - which fields go where,
+    cardinality, etc.) and the syntactic implementation of that model
+    (the technology used to express the concepts defined in the content
+    model). The normative sections below define the content model and
+    the XML Schema documents distributed with EML define the syntactic
+    implementation. For the foreseeable future, XML Schema will be the
+    syntactic specification, although it may change later.