Client:  Douglas County
Contact:  County Surveyor's Office, Terrie Franssen
Job Name:  2004/2005 Digital Orthophotos
Job Number: 1796

Primary Format:  GEOTIF, uncompressed, scan-lined (not tiled) with .tfw world file

Pixel Resolution:  1.5 ft./pixel
Rotation:  0 degrees (top is north)
Rectified Image Extents:  To extents of tile boundaries

Post-Processing/Resampling: SID images, Generation 2 @ 20:1 compression (good/high quality), default zoom levels
                            JPEG compression, Image Alchemy @ quality factor = 10 (low quality/high compression)
                            JPEG compression, Image Alchemy @ quality factor = 5 (even smaller files, lower quality)

Georeference filese to include:  GEOTIF (coordinates in TIF header), .tfw TIF world file, 
                                .jfw JPEG world file, .sdw SID world file and .TXT text metadata file	

DATUM:   Horizontal:  NAD 83/91 State Plane, Oregon South Zone (3602)
         Vertical:    NAVD 88 
CONTROL: Air-borne GPS control provided by:  ORION GPS, Contact:  John Putnam, P.L.S.
         Ground control provided by:  None/USGS Quad Map
UNITS:   International Feet

ACCURACIES:     Control / Aerotriangulation Results:  +/- 5'
	        Digital Orthophotos: Approximately +/- 20' Horizontal, or as supported by USGS DEM data accuracies
	        Vertical Accuracies:  Elevation data was not collected from this flight.
                                      Flight would support ASPRS Class I 10' contours, though additional ground 
                                      control may be required.

DATE(S) OF PHOTOGRAPHY:  Fall 2004:  9/22/04, 9/24/04, 10/12/04 (majority of flights)
                         Spring 2005:  3/14/05 (southern most flights + reflight for smoke near T 23 R 9,10)

SOURCE PHOTO SCALE:  1" = 1700' (1:20,400)
CAMERA:  BERGMAN PHOTOGRAPHIC SERVICES, INC., ZEISS TOP 30 (12" Lens)
CALIBRATION DATE:  Mar. 17, 2004
CALIBRATED FOCAL LENGTH:  305.045 MM

ORTHOPHOTO IMAGES PREPARED BY:  
  DAVID C. SMITH & ASSOCIATES, INC.; PORTLAND OREGON
  1734 SE Tacoma Street, Portland, Oregon, 97202
  Project contact:  Doug Smith, 503 232-5285; Doug@Davidsmithmapping.com

PROCESS:
  Color film was scanned on a Wehrli RM-6 roll feed photogrammetric scanner
  w/ infra-red scan scratch removal module.  Air-borne GPS control was aerotriangulated
  using as primary control using KLT Atlas softcopy bundle adjustment software.  
  Image points from existing USGS DRG's and USGS DEM's were used for rough verification 
  of aerotriangulation results.

  Orthophoto imagery was rectified to existing USGS DEM data with no additional supplemental 
  breaklines or data.  Bridges were edited/corrected to align with roads where visibly displaced.

  Orthophoto imagery was auto-mosaiced using KLT Atlas and OrthoVista 3.4.2 and then manually 
  reviewed / edited at all mosaic lines.
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