revised: 05-Feb-2015

NMBGMR Draft Geologic Data Model - v. 1.0.4
LINES: Contacts - Overlays

In the interests of standardization and interoperability, we are migrating our geologic maps into the USGS NCGMP09 data model. However, our well data model is still actively being used. Documentation for the NMBGMR geology data model is being provided for users with legacy data in this model. We also hope that it will provoke discussion in the ongoing effort to improve NCGMP09 and other models.


This feature class represents contacts bounding overlay polygons. These overlays may represent variations in lithology, texture, provenance, or some other field criteria of interest. These contacts are used to build polygons in Overlay_poly. These lines might not need to be displayed on standard bedrock geologic maps.

Field Name Field Alias Length
(text fields)
Field Type Field Value Default Allow Nulls? Attributes / Examples Description / Notes
FGDC_code " 16 String variable [null] TRUE 30.3.12 FGDC geologic symbol reference number.
OvrlyClass OverlayClass 50 String variable [null] TRUE unspecified, textural, provenance, depo-system, fault, map-boundary, shoreline, etc. Basis for overlay
IDmethod " 50 String CVD [null] TRUE see: IDmethod The basis for identification of this feature.
Confidence " 16 String CVD [null] TRUE unspecified, certain, probable, uncertain

Confidence regarding the existence/identification of this feature.

Exposure " 16 String CVD [null] TRUE unspecified, exposed, obscured, concealed Exposure of this feature at the surface.
OvrlyBndy OverlayBoundary 50 String CVD [null] TRUE unspecified, sharp, gradational, indistinct, intertonguing, wavy, irregular, planar, mapped extent, fault, intrusive Overylay boundary description
Name " 50 String variable [null] TRUE ? Feature name (will generally be NULL)
DsplyScale DisplayScale   Long Integer CVD 24000 TRUE see: DisplayScale Denominator of display scale: display feature at scales larger than number specified (=< denominator). Zero indicates data that should never be displayed.
SourceID " 128 String variable [null]   unknown; unspecified; Smith, 2006b [variable] Feature level metadata (who mapped this); related to bibliographic detail
Comments " 255 String variable [null] TRUE Free text e.g. identified from detailed stereo photos Comments about this particular feature.