PETROLEUM_WELLS_IN was created from data in the Indiana Geological Survey
Petroleum Well Database (Microsoft Access 2000). By the year 2001,
well locations in UTM (Universal Transverse Mercator)
coordinates had been tentatively determined for every well in Indiana.
The determination of these coordinates spanned some 7 years and involved a
variety of methods, including digitizing from 1:24,000 topographic maps,
batch processing software (GeoGraphix GES 97.5) for converting descriptive
locations to coordinate locations, and interactive on-screen measuring using
DRGs (digital raster graphics). The end result of these methods varied
somewhat and some current well spots may be slightly mislocated. Well
locations in the PDMS are being reviewed at present for accuracy. The
method by which a well is spotted in the PDMS, is recorded in the PDMS as
either (1) MEASURED, (2) GPS, or (3) IMPORTED.
(1) MEASURED refers to locations that have been measured on-screen using
Digital Raster Graphic Quads (DRG - digital USGS 1: 24,000 topographic maps) in ESRI
ArcView (before 2001) or ArcGIS. Measured locations generally are considered
accurate to the limits of the well description translated to a map
resolution of 1:24,000 (roughly 50 ft., however, the relative accuracy
of a location, as compared with other measured locations nearby, normally would be much greater).
(2) GPS refers to locations with coordinates determined by Global Positioning
System (GPS). Locations have not, as yet, been determined using GPS.
(3) IMPORTED refers to wells with a location determined by digitizing from
paper 1:24,000 topographic maps or by batch processing software.
All well locations in Indiana have been visually examined and compared with
earlier manually spotted well location maps at a scale 1 inch = 1 mile.
Obvious discrepancies have been corrected by measuring the well locations
on-screen on a DRG (digital USGS 1: 24,000 topographic maps). However,
lesser accuracy is likely for the well locations in many densely drilled areas.
These locations will eventually become MEASURED as time permits.
NOTE: Several wells in this dataset fall slightly outside the state
boundary as depicted on USGS 1:24,000-scale topographic
maps. The location of these wells have been verified, and the wells are
valid components of the PDMS Database. Therefore, clipping this dataset
to the state boundary would result in a spatial dataset that does
not fully reflect the contents of the IGS Petroleum Database (PDMS