revised: 05-Feb-2015

NMBGMR Draft Geologic Data Model - v. 1.0.4
Cross Sections

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.


Cross sections, identified on the geologic map by Sect_line, can be included as a separate CrossSection feature datasets within the geodatabase. Each cross section can be named Xsect_AA, Xsect_BB, etc. Besides having all the map data in one place, the advantage of including cross sections within the geodatabase is that they can be symbolized using the same symbol sets and fills used on the map. Each feature dataset will need to have a cartesian coordinate system with the same measurement units as the elevation field (usually feet for 7.5-minute quadrangles).

Each cross section will require: a frame consisting of a bottom and left and right sides and elevation tics and labels; Linear Features and their point symbology; and lithologic polygons. Except for the Exposure field (see below), the contact, fault, and lithologic polygon feature classes will have identical attibutes to the corresponding feature classes on the geologic map. The exposure field will be replaced with a boolean Subsurface field which will specify whether the feature class represents features in the sub-surface or features projected above the surface. This will allow alternate symbolization, like transparency effects, to be applied to features above the surface. Any other feature classes required for a cross section can be duplicated from feature classes used to construct the geologic map (like overlays, alteration, metamorphic grades, etc.)