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USDA - Natural Resource Conservation Service


National Digital Orthophoto Program(NDOP) DOQQ's


Table of Contents

SECTION 1  Application Software Compatibility
SECTION 2  File Structure


SECTION 1  Application Software Compatibility

The Digital Orthophoto Quarter Quads(DOQQ) files on this 
CD-ROM disk are ArcView 3.x, Arc/Info, FGI(FOCS Geospatial 
Interface), GRASS and ERDAS compatible.  This disk contains 
two files, a DOQQ raw file and a header file for each DOQQ.  
The DOQQ raw file has an extension of .bsq(1 Band B&W) or 
.bip(3 Band CIR).  The header file has an extension of .hdr. 
The header file is required by ArcView 3.x and Arc/Info.  
The header file is written to a projection datum of NAD83.
  

SECTION 2

This CD-ROM disk contains DOQQ's in a ISO 9660 Level 2 format.  
ISO 9660 Level 2 format supports up to 30 character filenames.  
The DOQQ filenames used on this disk are the "QUADRANGLE_NAME"
and "QUADRANT" embedded in the DOQQ raw file header.  The 
underline symbol is used instead of spaces for separation 
of name/quadrant. The following is an example of the first few 
lines in a DOQQ header file(New Keyword Format). 


BEGIN_USGS_DOQ_HEADER                                              *

QUADRANGLE_NAME "SUNSET FLAT"                                      *

QUADRANT NE                                                        *

NORTH_LATITUDE   37 37 30.000                                      *


etc...