Harford County Geological Fault Lines

DOCUMENTATION REVISION: 16 Oct 1995

DGN FILE NAME: getec.dgn

MGE PROJECT: /usr2/prj/apgdshe2

DESCRIPTION: Harford County Geological Fault Lines

GEOGRAPHIC EXTENT: Harford County

ENTITY CLASS: geology_tectonic

ENTITY NAME: getec_fault_line_l

ENTITY TYPE: line       LEVEL: 3   STYLE: 0   WEIGHT: 2   COLOR: 7

ATTRIBUTE TABLE NAME: gefault

COLUMN NAME       TYPE       COMMENTS
---------------   ------     -------------------------------------------------
mslink            integer    Feature linkage. 
mapid             integer    A system generated ID.
fault_id          char(20)   Unique identification number.
meta_id           char(20)   Foreign Key. (*)
img_set_id        integer    Foreign Key. (*)
fault_name        char(30)   Name of the geologic fault. (*)
penet_num         integer    Penetration number associated with the fualt. (*)
sdat_rel_d        char(15)   Reliability of the slip data for the fault. (*)
sep_horiz         double     Horizontal separation for the fault. (*)
sep_u_d           char(15)   Unit of measure for the separation above. (*)
sep_vert          double     Vertical separation for the fault. (*)
strike            double     The strike of the fault. (*)
strike_u_d        char(15)   Unit of measurement for the strike above. (*)
symmetry_d        char(6)    Boolean indicating whether fault is symmetrical.(*)
tdat_rel_d        char(15)   Descriptor for the reliability of fault top data(*)
depth_top         double     Vertical distance from surface to fault top. (*)
dip_src_d         char(15)   Descriptor for the source of fault dip data. (*)
dip_typ_d         char(15)   Descriptor for the type of dip for the fault. (*)
dip_angle         double     Estimated angle for the dip of the fault. (*)
dip_aximu         double     Estimated azimuth for the dip angle. (*)
azimu_u_d         char(15)   Units of measurement for the azimuth. (*)
faul_typ_d        char(15)   Descriptor for the type of the fault. (*)
feat_occ_d        char(15)   Descriptor for the feature occurrence. (*)
fault_desc        char(60)   Description of the geologic fault. (*)
abv_grnd          integer    Horizontal distance of fault at surface. (*)
below_grnd        integer    Horizontal distance of fault below ground. (*)
extent_u_d        char(15)   Units of measure for distances. (*)
geo_block         char(8)    Geologic block associated with the fault. (*)
interprt          char(20)   Interpreter of data with respect to the fault. (*)
data_rel_d        char(15)   Reliability of data regarding the fault. (*)
x_coord_1         double     X coordinate for line endpoint. (*)
y_coord_1         double     Y coordinate for line endpoint. (*)
z_coord_1         double     Z coordinate for line endpoint. (*)
x_coord_2         double     X coordinate for line endpoint. (*)
y_coord_2         double     Y coordinate for line endpoint. (*)
z_coord_2         double     Z coordinate for line endpoint. (*)
coordpj_id        char(20)   Foreign key to coordinate projection system. (*)
user_flag         char(6)    Locally controlled attribute which can be used to 
                              flag records. (*)

* Column appears in the Tri-Service standard, but information was not
  available in the original source; these fields are therefore blank.

DATA CREATION DATE: 16 Oct 1995

MAP PROJECTION: Universal Transverse Mercator (UTM)
                Zone 18
                Units:    Feet
                Spheroid: WGS84
                Datum:    WGS84

SOFTWARE VERSION: Intergraph MGE 5.0 / RIS 5.0

ORIGINAL SOURCE INFORMATION:
  Data was translated to Intergraph from the Arc/Info coverage
  geology/harford_fault.

  Media: 41" x 39" paper map
  Title: Geologic Map of Harford County
  Author/Agency: State of Maryland, Maryland Geological Survey, Geology of the
    crystalline rocks by D. Southwick, Geology of the coastal plain by J. Owens
  Date: 1968
  Scale: 1:62,500
  Projection: Unknown.
  Geographic Control: The map was tableted using latitude and longitude
    coordinates.  In Arc/Info the data was projected from lat/long to UTM,
    and then re-projected to change the datum to WGS84.  The datum conversion
    did improve the fit substantially, but it still did not match reference
    data well enough.  Georeferencing was further improved by identifying
    common landmarks in regional/tiger_county, regional/dlg100_hydro, and
    boundaries/dpw_bounds and transforming the geological data.
  Data Conversion: PC AutoCAD v12 was used to digitize the data.  The data was
    transferred to Arc/Info using a DXF transfer file.

ASSOCIATED DGN FILES: gesur.dgn

COMMENTS:
  Faults were shown as dashed lines that included some larger gaps.  Their
  exact extent was not always obvious.