Oregon Digital Ortho Quads
Oregon Digital Ortho Quad (DOQ) Processing
The CD number is based for the lat/long of the SE corner of the 1 degree block of 64 quads. (i.e. 44121). The CD name is composed of the east or west half of a 1:250,000 scale
quad, the name of the quad and the quadrant of the half (i.e. Bend West).
Key to files on CDROM:
1) README.HTML - This file.
2) SID Images - (i.e. s44121c5.sid) s+ohio code quad number.
3) SDW world file - (i.e. s44121c5.sdw) geo-referencing file for image.
4) document directory - A directory containing the following documentation files:
4a) INDEX.HTML - Contains: a) Primary county, b) State,
c) quad code, d) producing agency (GS = USGS, FS = USFS), e) file size in MB, f) pixel size in meters,
g) quadname, and h) image date(s).
4b) INDEX.JPG - A JPEG image showing the location of the DOQ's within Oregon.
4c) or250.jpg - A JPEG image showing the 1:250,000 quad tiles in Oregon.
4d) DOQ_QQ.HTML - A generic USGS metadata file for orthos in HTML format.
The images in this directory were created by USGS & the USFS and are in the
public domain. No warranty or liability is given or implied for the quality of the
data. Errors or omissions should be reported to the Oregon Geospatial Data (OGDC)
Clearinghouse at 503-378-2166.
The images have been projected in to the Oregon Geographic
Information Council (OGIC) standard projection (Oregon Lambert).
Map Projection:Lambert Conformal Conic
Grid Coordinate System:Oregon Lambert Projection
PARAMETERS
43 00 00.000 /* 1st standard parallel
45 30 00.000 /* 2nd standard parallel
-120 30 0.000 /* central meridian
41 45 0.000 /* latitude of projection's origin
400000.00000 /* false easting (meters), (1,312,335.958 feet)
0.00000 /* false northing (meters)
Horizontal Units:International Feet (.3048 meters or 3.280839895 feet / meter)
Horizontal Datum:North American Datum of 1983-91 (HPGN)
Vertical Datum:North American Vertical Datum of 1988
Spheroid:GRS 1980
A description of the coordinate system is found at the OGDC page:
http://www.gis.state.or.us
The process used to create the files and a current status map may be found at:
http://www.gis.state.or.us/doq
The USGS DOQ web page may be found at:
http://www-wmc.wr.usgs.gov/doq/
June 22, 2001