Chromite deposits in central part Stillwater Complex, Sweet Grass County,
Montana: A digital database for the geologic map of the east slope of Iron
The digital geologic map of the east slope of Iron Mountain, Sweet Grass
County, Montana was prepared from preliminary digital datasets digitized by
Optronics Specialty Co., Inc. from a paper copy of plate 10 from UGSG Bulletin
1015-D (Howland, 1955).The files were prepared and transformed to the Montana
State Plane South projection by Helen Z. Kayser (Information Systems Support,
Inc.). Further editing and attributing was performed by Lorre A. Moyer in
2001. The resulting spatial digital database can be queried in many ways to
produce a variety of derivative geologic maps.
This GIS consists of two major ArcInfo datasets: one line and polygon file
(ironmtn) containing geologic contacts and structures (lines) and geologic map
rock units (polygons), and one point file (ironmtnp) containing structural
Howland, A.L., and Moyer, L.A., 2001, Chromite deposits in central part Stillwater Complex, Sweet Grass County, Montana: A digital database for the geologic map of the east slope of Iron Mountain: U.S. Geological Survey Open-File Report 01-321, U.S. Geological Survey, Menlo Park, CA.
Grid_Coordinate_System_Name:State Plane Coordinate System State_Plane_Coordinate_System:
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 0.000004
Ordinates (y-coordinates) are specified to the nearest 0.000004
Planar coordinates are specified in Survey feet
The horizontal datum used is North American Datum of 1927.
The ellipsoid used is Clarke 1866.
The semi-major axis of the ellipsoid used is 6378206.4.
The flattening of the ellipsoid used is 1/294.98.
U.S. Geological Survey Open-File Report 01-321 contains a detailed
description of each attribute code and a reference to the associated map
symbols on the map source materials. The GIS includes a geologic linework
arc attribute table, ironmtn.aat, that relates to the ironmtn.con (contact
look-up table), ironmtn.st2 (structure look-up table), and the ironmtn.ref
(source reference look-up table) files; a rock unit polygon attribute table,
ironmtn.pat, that relates to the ironmtn.ru (rock unit look-up table) and
ironmtn.ref (source reference look-up table) files; and a geologic map
symbol point attribute table, ironmtnp.pat, that relates to the ironmtnp.sym
(structural point data look-up tables) and ironmtnp.ref (source reference
look-up table) files.
In 2000, the U.S. Geological Survey contracted Optronics Specialty Co., Inc.
(Northridge, CA) to scan and vectorize the geologic map of the east slope of
Iron Mountain (Howland, 1955, plate 10). Helen Z. Kayser (contractor)
transformed the GIS provided by Optronics from scanner inches to a state plane
coordinate system (Montana South). Lorre A. Moyer then edited and attributed
the spatial digital data files with an interim geologic data model in 2001.
This dataset was developed to provide a geologic map GIS of the east slope of
Iron Mountain, Sweet Grass County, Montana for use in future spatial analysis
by a variety of users. These data can be printed in a variety of ways to
display various geologic features or used for digital analysis and modeling.
This database is not meant to be used or displayed at any scale larger than
1:3077 (for example, 1:2000 or 1:1500).
Optronics Specialty Co., Inc. (Northridge, CA) scanned and vectorized the
geologic map of the east slope of Iron Mountain (Howland, 1955, plate 10).
Helen Z. Kayser (contractor) transformed the GIS provided by Optronics from
scanner inches to a state plane coordinate system (Montana South). Lorre A.
Moyer then edited and attributed the spatial digital data files with an
interim geologic data model.
Date: 05-Dec-2001 (process 2 of 2)
Creation of original metadata record
Person who carried out this activity:
How consistent are the relationships among the observations, including topology?
Polygon and chain-node topology present. Segments making up the outer and
inner boundaries of a polygon tie end-to-end to completely enclose the area.
Line segments area set of sequentially numbered coordinate pairs. No
duplicate features exist nor duplicate points in a data string.
Intersecting lines are separated into individual line segments at the point
of intersection. Point data are represented by two sets of coordinate
pairs, each with the same coordinate values. All nodes are represented by a
single coordinate pair which indicates the beginning or end of a line
segment. The neatline was generated by mathematically generating the four
sides of the quadrangle, densifying the lines of latitude and projecting the
file to Montana State Plane zone 4526.
This digital database is not meant to be used or displayed at any scale larger
than 1:3077 (such as 1:2000).
Any hardcopies utilizing these data sets shall clearly indicate their source.
If the user has modified the data in any way they are obligated to describe
the types of modifications they have performed on the hardcopy map. User
specifically agrees not to misrepresent these data sets, nor to imply that
changes they made were approved by the US Geological Survey.
The U.S. Geological Survey (USGS) provides these geographic data "as is".
The USGS makes no guarantee or warranty concerning the accuracy of
information contained in the geographic data. The USGS further makes no
warranties, either expressed or implied as to any other matter whatsoever,
including, without limitation, the condition of the product, or its fitness
for any particular purpose. The burden for determining fitness for use lies
entirely with the user. Although these data have been processed
successfully on computers at the USGS, no warranty, expressed or implied, is
made by the USGS regarding the use of these data on any other system, nor
does the fact of distribution constitute or imply any such warranty.
In no event shall the USGS have any liability whatsoever for payment of any
consequential, incidental, indirect, special, or tort damages of any kind,
including, but not limited to, any loss of profits arising out of use of or
reliance on the geographic data or arising out of the delivery,
installation, operation, or support by USGS.
This digital geologic map GIS of the east slope of Iron Mountain, Sweet
Grass County, Montana is not meant to be used or displayed at any scale
larger than 1:3077 (for example, 1:2000).