GeMS — Appendix 5

Overview

[Names of sections in this document have been highlighted in bold type. Substantive changes to the GeMS schema from NCGMP09 v.1.1 (U.S. Geological Survey National Cooperative Geologic Mapping Program, 2010) are indicated by magenta type. Other changes listed are modifications made to this documentation since NCGMP09 v.1.1]

Throughout document —

Changed name of schema from NCGMP09 to GeMS
Changed title of documentation to “GeMS (Geologic Map Schema)—A Standard Format for the Digital Publication of Geologic Maps”
Modified authorship statement
Added Table of Contents to front matter of document
Made revisions for clarity
Added several footnotes to help clarify terminology
Changed most instances of “geodatabase” to “database”
Reduced use of first-person voice
Recast diagrams of fields (and their values) into numbered tables that can be easily located using the Table of Contents
For all numbered tables (as applicable):

Added “Field name”, “Description”, and “Notes on usage” column headings to improve structure and organization
Made significant revisions for clarity, consistency, and completeness
Highlighted (using magenta bold type) the contents of fields that must be defined in Glossary table where applicable and explained this red bold type in bracketed headnotes
Moved descriptions of Type (or similar) fields to top of tables and moved descriptions of TableName_ID fields to bottom. Although field order is not prescribed in GeMS, a consistent field order makes the schema easier to comprehend; in addition, ArcGIS workflow considerations make it desirable to have the Type field (or similar) first
Removed RuleID and Override fields and values (inclusion of these fields in GeMS is perceived by the USGS–AASG–DMT community as an impediment to understanding the schema by those who do not use Esri’s cartographic representations; furthermore, those who use cartographic representations can always add these optional fields)
Stated that Notes fields are always optional
Changed “Nulls OK” to “Null values permitted”

Renumbered appendixes from A–E to 1–5

In Introduction section —

Changed intent from “proposes a schema” to “describes and defines a schema”
Changed “two decades” to “three decades”
Added evolution of the schema after NCGMP09 v.1.1
Deleted former Contents and Review, Comment and Revision sections
Moved Acknowledgments section to front matter, before Table of Contents

In Design Considerations section —

Moved Content of a Traditional Geologic Map and following sections into new Content of a Geologic Map section (see below)

In Content of a Geologic Map section —

Highlighted (using MAGENTA ALL CAPS bold type) fundamental map content within GeMS that is further discussed in sections that follow, where the GeMS schema is described in detail
Highlighted (using BLACK ALL CAPS bold type) secondary and supporting map content whose digital form is prescribed herein
Highlighted (using italic bold type) secondary and supporting map content for which a digital form is not specified herein
Made minor revisions to Symbolization discussion for clarity, consistency, and completeness
In Extensions to Traditional Geologic Map Content section:

Made significant revisions to Glossary of Terms section (renamed from Glossary)
Made significant revisions to Classification of Geologic Materials (renamed from General Lithology)
In Feature-Level Metadata section:

Significantly rewrote Locational Confidence (Spatial Accuracy) section; added new example picklist (table 1) for LocationConfidenceMeters values (goal is to better explain intent of LocationConfidenceMeters attribute and better illustrate its use)
Added new example picklist (table 2) for IdentityConfidence values to Scientific Confidence, Identity Confidence, and Existence Confidence section

Added new Working with Multiple Feature Attributes section

In Naming Database Elements section:

Changed CamelCase to the more accurate PascalCase
Reordered bullets to separate cognitive concerns from coding concerns

Revised Transparent Identifiers section for clarity
In File Formats section (renamed from Open File Formats):

Specified use of .gdb only (not .mdb)
Substantially revised discussion of text, table, and image formats for clarity

In Required, As-Needed, and Optional Elements of a Digital Geologic Map Publication section (renamed from Required, As-Needed, and Optional Contents of a Digital Geologic Map Publication) —

Removed mentions of mapXYZ-mdb.zip, base.mdb, in response to suggestions to deprecate .mdb format
Renamed base.gdb to mapXYZ-base.gdb
Recast list of required, as-needed, and optional map elements into tables 3, 4, and 5 for clarity

In The Database Design section (renamed from The Geodatabase Design) —

Noted, in initial paragraph, that additional optional elements are permitted by schema
In General Considerations section:

Renumbered figures 2A, 2B, and 2C to figures 2, 3, and 4, respectively
Added new Field Hygiene section:

Clarified that schema does not, in general, prescribe field lengths
Stated that required fields should not be deleted and that repurposing of required fields is prohibited
Described use of explicit null values
Stated that Notes fields are optional and may be omitted
Moved paragraphs 2, 3, and 4 of The Database Design section (originally named The Geodatabase Design) into Field Hygiene section
Added four new tables illustrating use of primary keys (TableName_ID field) and foreign keys TableNameID field)

In Type, MapUnit, Label, and Symbol Fields section (renamed from Type, Label, and Symbol Fields):

Added separate discussion of MapUnit field
Expanded discussion of Label field and how Label field differs from MapUnit field, especially when used with FGDCGeoAge font
Added new table 10 showing examples of values in Type, Symbol, and Label fields in a point feature class and resulting map images
Added new table 11 showing examples of values in MapUnit, IdentityConfidence, Symbol, and Label fields in MapUnitPolys feature class and resulting map images

In Directional Lines section:

Expanded discussion of “right-hand rule”

In Required Elements section:

In GeologicMap (Feature Dataset) section:

In MapUnitPolys (Polygon Feature Class) section:

Added further discussion of using FGDCGeoAge font to produce geologic age symbol characters
Added separate Topology Rules section

In ContactsAndFaults (Line Feature Class) section:

Added separate Topology Rules section

In DescriptionOfMapUnits (Nonspatial Table) section:

Deleted former table 1 and references thereto (material is now covered in appendix 3)
Deleted paragraph suggesting development of more structured DMU descriptions
In table 14:

Revised Name and Description fields to state that headings should be entered in the Name field and associated headnotes, if present, should be entered in the Description field
Added footnotes to Name and FullName fields stating that formal names should be verified in Geolex (see https://ngmdb.usgs.gov/Geolex/)
Added sentence to Name field stating that text in this field should have no font or hierarchy specifications
Rewrote HierarchyKey field description for clarity
Added example showing how ParagraphStyle field works (that is, values are type and paragraph specifications, which are defined in Glossary table)
Replaced GeneralLithology and GeneralLithologyConfidence fields with GeoMaterial and GeoMaterialConfidence fields

Added new Notes on the Content of the Description Field section that contains extensive new material on the content and writing of map-unit descriptions, mostly quoted from USGS’s “Suggestions to Authors of the Reports of the United States Geological Survey—Eighth Edition” (U.S. Geological Survey, in press) and R.E. Wells (USGS, written commun., 2010)
Added new Populating the DescriptionOfMapUnits Table section:

Moved discussion of GeoMaterial and GeoMaterialConfidence fields here
Added short paragraph that refers reader to appendix 3, which illustrates construction of HierarchyKey values

Added new Order and Rank of Map Units section:

Expanded discussion describing use of ParagraphStyle values

In DataSources (Nonspatial Table) section:

Added optional URL field
Deleted sentence at end that refers to ChangeLog

Added new GeoMaterialDict (Nonspatial Table) section (and new table 17)
Moved DataSourcePolys (Polygon Feature Class) section to Examples of Other As-Needed Feature Classes section (in As-Needed Elements section)
In Glossary (Nonspatial Table) section:

Deleted Qualifier and Property fields from list of fields for which all values must be defined in Glossary table (fields are within ExtendedAttributes table, which has been removed from this version)
Deleted GeoMaterial field from list of fields whose values must be defined in Glossary, as these values are now defined in GeoMaterialDict table (see appendix 1)
Deleted sentence “Lithology terms used in GeneralLithology must not be redefined from the NGMDB standard” from discussion (field name has changed, and topic is addressed in GeoMaterialDict section)

In As-Needed Elements section:

Clarified that, although GeMS does not prescribe the use of any particular as-needed feature classes, any feature class described here that is used by a GeMS database should conform to these descriptions
In Guidelines for Naming and Designing Additional Feature Classes section (renamed from Guidelines for Naming and Designing Additional Polygon, Line, and Point Feature Classes):

Changed “CamelCase” to the more accurate term “PascalCase”
Deleted last sentence requesting comments on naming of feature classes

In Structure of Point Data section:

In Point Feature Classes in General section:

Added short paragraph explaining utility of MapUnit field
Changed “Sample-oriented point feature classes shall have the fields” to “We also recommend that sample-oriented point feature classes include certain additional fields”
Renamed StationID field to StationsID field
Deleted MapX and MapY fields, as they are redundant in a feature class

Split former Some Examples of As-Needed Feature Classes section into two new sections (Examples of As-Needed Point Feature Classes and Examples of Other As-Needed Feature Classes)
In new Examples of As-Needed Point Feature Classes section:

In OrientationPoints (Point Feature Class) section:

Deleted last sentence that referred to ExtendedAttributes table
In table 22:

Added StationsID and MapUnit fields, for consistency with Point Feature Classes in General section
Renamed DataSourceID field to LocationSourceID field
Added OrientationSourceID field

In GeochronPoints (Point Feature Class) section:

In table 23:

Renamed StationID field to StationsID field
Renamed DataSourceID field to LocationSourceID field
Added AnalysisSourceID field
Added ErrorMeasure field

In Stations (Point Feature Class) section:

Added short paragraph explaining utility of ObservedMapUnit field

In table 24:

Changed “Null values not permitted” for MapUnit field to “Null values permitted only for points outside the extent of MapUnitPolys feature class”
Added “suggest setting default value = 0 ( = display at all scales)” for PlotAtScale field

In table 25:

Added “and affiliation” for Observer field

Added new MapUnitPoints (Point Feature Class) section

In new Examples of Other As-Needed Feature Classes section:

Added new MapUnitLines (Line Feature Class) section
In IsoValueLines (Line Feature Class) section:

In table 28:

Added ValueConfidence field

In Overlay Polygons (the MapUnitOverlayPolys and OverlayPolys Polygon Feature Classes) section (renamed from OtherPolys):

Added discussion of MapUnitOverlayPolys feature class
Renamed OtherPolys feature class to OverlayPolys feature class
Added separate Topology Rules section
Explanatory text revised significantly

In DataSourcePolys (Polygon Feature Class) section:

Changed from a required element to an as-needed element
Made minor revisions to introductory paragraph
Added separate Topology Rules section
Deleted topology rule “Polygon boundaries may in part be coincident” (deemed unnecessary)

Moved RepurposedSymbols (Nonspatial Table) section to Symbolization section below

In Symbolization section —

Made substantial revisions for clarity
Added new URL for Esri’s Geologic Mapping Template
Changed “we also require provision of an ArcReader document” to “we also suggest that an ArcReader document (.pmf file) be provided” (that is, changed inclusion of ArcReader document from required to optional)

In Shapefile Version of the Database section (renamed from Shapefile Versions of the Database) —

Dropped requirement for “simple” shapefile version and all references to its construction
Deleted Simple Version section
Deleted Open Version section

In Appendix 1. Terms and Definitions for the GeoMaterial and GeoMaterialConfidence Fields (renamed from Appendix A. Lithology and Confidence Terms for GeneralLithology) —

Made minor changes for clarity
Removed reference to future evolution of term list
Added new Scope and Intent section
In GeoMaterial Terms section (renamed from GeneralLithology):

Under term Sedimentary rock, added term Chert
Under term Carbonate rock, added terms Limestone and Dolomite
Under term Extrusive igneous material, added term Volcanic mass flow
Under term Regional metamorphic rock, of unspecified origin, added term Lower-grade metamorphic rock, of unspecified origin
Under term Metasedimentary rock:

Added term Meta-carbonate rock
Deleted term Marble

Under term Metaigneous rock:

Added term Meta-ultramafic rock
Added term Meta-mafic rock
Added term Meta-felsic and intermediate rock
Added term Meta-volcaniclastic rock

Numerous minor changes in term descriptions, for clarity and consistency
Moved Soller (2009) reference into new Reference Cited in Appendix 1 section
Placed references to sources of GeoMaterial terms into new Published and Unpublished Sources forTerms and Definitions (Modified as Needed) in the GeoMaterial Field, as Listed in Appendix 1 section

In Appendix 2. Optional Database Elements (renamed from Appendix B. Optional Elements) —

In Correlation of Map Units (Feature Dataset) section:

Deleted second paragraph
Added discussion of CMUMapUnitLines and CMUMapUnitPoints feature classes
In CMUMapUnitPolys (Polygon Feature Class) section:

Expanded discussion of ghost boxes

Deleted CMUPoints (Point Feature Class) section

Added new MiscellaneousMapInformation (Nonspatial Table) section because new MiscellaneousMapInformation table has been added
Deleted ExtendedAttributes and GeologicEvents sections because ExtendedAttributes and GeologicEvents tables have been deleted (to our knowledge, no one in the USGS–AASG–DMT community has implemented either the ExtendedAttributes or the GeologicEvents tables in a published database; however, this does not preclude the implementation of either table)
Added new Deprecated Nonspatial Tables section that refers those interested to NCGMP09 v.1.1 documentation for descriptions of ExtendedAttributes and GeologicEvents tables
Added reference for NCGMP09 v.1.1 and put it in new Reference Cited in Appendix 2 section

Deleted former Appendix C. Building a Compliant Database because this material, in revised form, appears in the wiki associated with the GeMS toolkit (see https://github.com/usgs/GeMS_Tools)

Added new Appendix 3. Parsing a Description of Map Units (DMU) into the DescriptionOfMapUnits Table and the HierarchyKey Field —

In new The DescriptionOfMapUnits Table section, added explanation of, and examples that illustrate, how to translate the contents of a Description Of Map Units (DMU) into the DescriptionOfMapUnits table
In new The HierarchyKey Field section, added description of, and examples that illustrate, the HierarchyKey field, giving rules for its construction
Placed references in new References Cited in Appendix 3 section

In Appendix 4. Frequently Asked Questions (FAQs) —

Added new question How do I get started?
For the question How do I represent dikes?, changed “OtherLines” in the second choice to “GeologicLines” (“OtherLines” was an error in v.1.1)
Added new questions How do I represent other small bodies of rock?, What about bedrock contacts under alluvium?, and How do I encode a stack-unit map? That is, I’d like to represent bedrock and overlying surficial geology in the same GeMS database. How might I do this?
For the question The Notes field is empty for all records in my ContactsAndFaults feature class. May I delete this field?, changed answer to indicate that Notes fields are optional and may be deleted
For the question What about my fault map? It doesn’t show geologic units, changed answer to suggest the encoding of faults in GeologicLines rather than ContactsAndFaults
For the question My report has an auxiliary map that shows the distribution of sedimentary facies in the Miocene. Where does this map fit in this design?, changed “feature class” in second sentence to “feature dataset” (“feature class” was an error in v.1.1)
For the question How can I tell if a database is GeMS-compliant?, substantially expanded answer
For the question How do I use a GeMS-compliant database to make a publication-quality map graphic?, made major revisions for clarity and completeness
Deleted question I’ve got a better design for a standard geologic-map database. How do I go about getting this proposal changed?
Placed references in new References Cited in Appendix 4 section

Added new Appendix 5. Changes from NCGMP09 v.1.1 to GeMS

References Cited in Appendix 5

U.S. Geological Survey, in press, Suggestions to Authors of the Reports of the United States Geological Survey, Eighth edition: U.S. Geological Survey website.

U.S. Geological Survey National Cooperative Geologic Mapping Program, 2010, NCGMP09—Draft standard format for digital publication of geologic maps, version 1.1, in Soller, D.R., ed., Digital Mapping Techniques ’09—Workshop Proceedings: U.S. Geological Survey Open-File Report 2010–1335, p. 93–146, 4 appendixes, https://pubs.usgs.gov/of/2010/1335/pdf/usgs_of2010-1335_NCGMP09.pdf.