Minnesota Geological Survey
Southwestern Minnesota Regional Assessment; RHA-2
GIS data base. 1996

This index lists the significant covers used in the generatation of
the plates for the Southwestern Minnesota Regional Assessment.
Digital work was performed from summer of 1993 - winter 1995.

The cover names include an identifing prefix of sw.

Base layers (except township) modified from TIGER census data.  
Surficial geology linework by Carrie Patterson & other MGS staff 
with digital editing & cleanup by MGS GIS staff.

All coverages were converted from single precision, UTM zone 15 -
shifted, NAD27 to double precision, UTM zone 15, unshifted NAD83 in
February of 2008.


Base layers:
 
swpgpa	 =  polygon cover of the project area
swpglk 	 =  modified polygon cover of lakes
swlnhy 	 =  line cover of rivers
swlnrd 	 =  line cover of major highways, also points for hiway symbols
swpgco 	 =  polygon cover of county outlines
swpgmcd  =  polygon cover of township-range grid
swptll	 =  point cover for latitude-longitude tics


Surficial Geology:

swpgsg   =  polygon cover of surficial geology units
swlnsg   =  line cover of surficial geology linear features
swptrs   =  point cover of sand and gravel pits and quarries
swptp1   =  point cover of Giddings, outcrop, cuttings and bucket auger sites 
swlngp   =  line/point cover of seismic lines and because they are so small
            at map scale a point to identify as a marker symbol on map 


Bedrock topography and Drift Thickness:

swptbt  =  point cover of bedrock control locations from drilling logs
swlnbt  =  line cover of bedrock topographic contours
           (derived from generating a grid (POINTGRID) from the bedrock control 
           points, converting those grid points to an arc cover (GRIDARC). 
           Dale Setterholm then interpreted the contours and edited them by hand
           to create the final bedrock topography linework, which was then digitized
           for this coverage.