MN DNR PHOTO CD ARCHIVE

This compact disk contains scanned images of aerial photographs originally flown for the U.S.Geological Survey.  They were recorded in 2001 as part of a Minnesota Department of Natural Resources program to organize and preserve old aerial photography.

PHOTO PROJECT:   Photographs on this disk were taken vertically with a 9"x9" format metric camera using black-and-white negative film. 

Project Code:   GS-SD
Original Scale:   1:23,600

Flown:     Project completed 24 April 1952.

Coverage:     DNR Engineering 15' quadrangles W21 and W22,  named Chatfield and Lewiston.  W21 now contains Chatfield, Eyota, Pilot Mound and St. Charles 7.5' quadrangles.  W22 now contains Arendahl, Lewiston, Rushford W and Utica 7.5’ quadrangles.  The coverage area includes portions of Fillmore, Olmsted and Winona Counties, Minnesota.      

Airphoto Contractor: Park Aerial Surveys, Louisville KY

Camera Focal Length: 154.91mm

The SD project is recorded on a single CD.  Photos in this project were originally taken with greater than 50 per cent endlap; to conserve space, only alternate (odd-numbered) photos have been scanned and recorded, with some exceptions.  Gaps in coverage may exist. 

FILE FORMAT:  All photo files are in uncompressed TIFF format, and can be opened, viewed and printed using standard image handling software.  All are oriented with north upwards.  They have not been rectified or georeferenced; users who wish to import them into geographic information systems must find means of fitting them to whatever datasets they are to be employed with.

FILE NAMES:   Photos are identified by project code, roll number and frame number, using the convention XXXyyZZZ.tif:
     
     XXX = project code
     yy = roll number within project
     zzz = frame number within roll
     tif = Tag Image File Format

INDEXING:  The index directory contains two 30 x 60-minute maps in GIF format (the Austin MN and LaCrosse WI/MN USGS 1:100,000 topographic quadrangles) showing flight lines and photo centers.  Like the photos, they can be opened and viewed in standard imaging software.  Approximately every fourth photo center is labeled.  A subdirectory contains scanned index photomosaics of the Lewiston 15’ quadrangle only.

PRODUCTION:  TIFF files were produced by scanning 9"x9" black-and-white prints on desktop scanners at 300 pixels per inch using Hewlett-Packard Precision Scan Pro software.  CDs were produced with Adaptec Easy-CD Pro software.

Inquiries may be directed to:

DNR Resource Assessment 
413 SE 13th Street
Grand Rapids MN 55744
218-327-4449

or to:

DNR Engineering Bureau
500 Lafayette Road
St. Paul MN 55108 
651-296-2119