Digital orthophoto quadrangle

Image:DOQ.gif

A digital orthophoto quadrangle

{{cite web

|url=http://edc2.usgs.gov/pubslists/factsheets/fs05701.pdf

|title=USGS GeoData Digital Orthophoto Quadrangles

|work=USGS Fact Sheet 057-01

|publisher=United States Geological Survey

|date=May 2001

|url-status=dead

|archiveurl=https://web.archive.org/web/20100527103950/http://edc2.usgs.gov/pubslists/factsheets/fs05701.pdf

|archivedate=2010-05-27

}}

(DOQ) is aerial photography or satellite imagery that has been corrected so that its pixels are aligned with longitude and latitude lines, and have a narrowly defined region of coverage. This is a widely used format introduced by United States Geological Survey (USGS). The correction technique is called image rectification and is a large part of photogrammetry.

{{cite web

|url=http://www.univie.ac.at/Luftbildarchiv/wgv/intro.htm

|title=Introduction to Photogrammetry

|work=The Aerial Archive

|publisher=Institute for Prehistory and Protohistory of the University of Vienna

|url-status=dead

|archiveurl=https://web.archive.org/web/20060924194938/http://www.univie.ac.at/Luftbildarchiv/wgv/intro.htm

|archivedate=2006-09-24

}}

DOQs produced by the USGS cover an area measuring 7.5-minutes longitude by 7.5-minutes latitude (the same area covered by a USGS 1:24,000-scale topographic map, also known as a 7.5-minute quadrangle) or 3.75-minutes by 3.75-minutes. The second format is also known as a digital orthophoto quarter quadrangle (DOQQ) because each covers one quarter of a quadrangle (four 1:12,000-scale DOQQs display the same area as one 1:24,000-scale DOQ).

{{cite web

| url = http://online.wr.usgs.gov/ngpo/doq/doq_history.html

| title = USGS DOQ History

| publisher = United States Geological Survey: Western Region

| accessdate = April 24, 2012

}}

{{cite web

| url = http://egsc.usgs.gov/isb/pubs/booklets/usgsmaps/usgsmaps.html#7.5-minute

| title = USGS 7.5-minute maps

| publisher = United States Geological Survey: Eastern Geographic Science Center

| accessdate = April 24, 2012

| archive-date = March 29, 2014

| archive-url = https://web.archive.org/web/20140329131119/http://egsc.usgs.gov/isb//pubs/booklets/usgsmaps/usgsmaps.html#7.5-minute

| url-status = dead

}}

{{cite web

|url=http://rockyweb.cr.usgs.gov/software/doqhead/readme.doq

|title=DOQHEAD Toolkit

|publisher=United States Geological Survey: Rocky Mountain Mapping Center

|date=June 22, 1998

|url-status=dead

|archiveurl=https://web.archive.org/web/20111018011505/http://rockyweb.cr.usgs.gov/software/doqhead/readme.doq

|archivedate=2011-10-18

}}