Mark A. Fonstad James J. Major James T. Dietrich Gabriel W. Gordon Charles M. Cannon James E. O'Connor 20240222 raster digital data https://doi.org/10.5066/P1ELGYBG This data release consists of high quality georeferenced orthophoto mosaics of a 160 kilometer long portion of the Columbia River between Portland and The Dalles, Oregon created from aerial photographs collected in 1935 by the U.S. Army Corps of Engineers. The dataset comprises three GeoTIFF files, each covering about 40-60 kilometers. This metadata document summarizes the entire data release. See attached metadata records for information on the individual mosaics. The original photographs were acquired prior to completion of three major dams in this reach of the Columbia River. Therefore, the dataset is useful for comparison of pre-dam valley-bottom conditions to modern conditions along the Columbia River corridor. 193509 ground condition Complete None planned -122.8092 -120.8834 45.7735 45.4269 ISO 19115 Topic Category inlandWaters imageryBaseMapsEarthCover USGS Thesaurus aerial photography geospatial datasets None structure from motion historical imagery USGS Metadata Identifier USGS:65a1dad5d34e5af967a450d7 Geographic Names Information System (GNIS) Mosier The Dalles Hood River Oregon Columbia River Wishram Washington Portland Vancouver Camas Bridal Veil None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Mark A. Fonstad University of Oregon Associate Professor physical

107F Condon Hall

Eugene OR 97403 5413464208 fonstad@uoregon.edu OrthophotoOfColumbiaRiver1935_browse.jpg Browse image of the entire 1935 orthophoto collection. JPEG Aerial photographs were acquired and provided by U.S. Army Corps of Engineers, orthophotographs were created by University of Oregon Maarten Bakker Stuart N. Lane 20161108 publication https://doi.org/10.1002/esp.4085 Patrice E. Carbonneau James T. Dietrich 20160802 publication https://doi.org/10.1002/esp.4012 James T. Dietrich 20160101 publication https://doi.org/10.1016/j.geomorph.2015.05.008 Mark A. Fonstad James T. Dietrich Brittany C. Courville Jennifer L. Jensen Patrice E. Carbonneau 20121108 publication https://doi.org/10.1002/esp.3366 Mark A. Fonstad James J. Major Jim E. O'Connor James T. Dietrich 2017 publication Fonstad, M. A., Major, J. H., O'Connor, J. E., and Dietrich, J. T. (2017, December). Reconstructing the 1935 Columbia River Gorge: A Topographic and Orthophoto Experiment. In AGU Fall Meeting Abstracts (Vol. 2017, pp. EP34B-05). https://ui.adsabs.harvard.edu/abs/2017AGUFMEP34B..05F/abstract Mike R. James Stuart Robson 20140531 publication https://doi.org/10.1002/esp.3609 Quinn W. Lewis Edward Park 20170809 publication https://doi.org/10.1080/24694452.2017.1343658 Thad Wasklewicz Zhen Zhu Paul Gares 20171030 publication https://doi.org/10.1186/s40645-017-0144-7 Comparison of the 1935 orthophotographs to National Agriculture Imagery Program digital orthophotographs from 2005 suggest that errors in image alignment are generally less than 5 meters, but may be locally greater than 15 meters. Contact Mark Fonstad for more details pertaining to data quality and accuracy. No formal logical accuracy tests were conducted. Data are complete for areas where photos were georeferenced within study area. No formal horizontal accuracy tests were performed. Comparison of the 1935 orthophotographs to National Agriculture Imagery Program digital orthophotographs from 2005 suggest that errors in image alignment are generally less than 5 meters, but may be locally greater than 15 meters. Contact Mark Fonstad for more details pertaining to positional accuracy. U.S. Army Corps of Engineers, Portland District Office 1935 raster digital data Digital and/or Hardcopy 193509 ground condition Columbia River Aerial Photographs, 1935 The scanned aerial photographs are the source of the orthophotographs. U.S. Department of Agriculture, Farm Service Agency, Aerial Photography Field Office 2005 remote sensing image aerial photograph 20050718 20050804 ground condition NAIP 2005 The aerial photographs provided a base layer to compare positional accuracy of the 1935 orthophotos. Photographs were acquired courtesy of the U.S. Army Corps of Engineers, Portland District, scanned by Chris J. Edwards in May 2015. Supplemental scans were conducted in February 2016 by Geoffrey Marcus, University of Oregon. 2015 718 9-inch by 90inch stereo aerial photographs with approximately 60% overlap (approximate scale 1:16,000) were scanned at approximately 1200 dpi resolution, rotated, decollared, and tonally corrected. They were georectified using Agisoft Metashape version 1.5 and control points visible from in Lidar acquired between 2007 and 2015. Publications describing structure from motion (SfM) methods and error assessment are included in the cross-reference section of this document. Contact Mark Fonstad for more details pertaining to methods and software used. 2017 Mark A. Fonstad University of Oregon Associate Professor physical

107F Condon Hall

Eugene OR 97403 5413464208 fonstad@uoregon.edu Each mosaic was converted from geodatabase raster format to GeoTiff using ArcGIS Pro 3.1.1. 20231012 Distorted, blurry, or blank portions of each mosaic were clipped out using ArcGIS Pro 3.1.1. 20240213 HillsboroPortlandCamas_Ortho.tif 2 band raster geospatial data file. Producer Defined Value Unique numeric values contained in each raster cell. Producer Defined 0.0 255.0 BridalVeilBonnevilleHoodRiver_Ortho.tif 2 band raster geospatial data file. Producer Defined Value Unique numeric values contained in each raster cell. Producer Defined 0.0 65535.0 WhiteDallesWishram_Ortho.tif 2 band raster geospatial data file. Producer Defined Value Unique numeric values contained in each raster cell. Producer Defined 0.0 65535.0 GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. GeoTIFF https://doi.org/10.5066/P1ELGYBG None 20240222 U.S. Geological Survey, SOUTHWEST REGION Gabriel W. Gordon Geologist mailing address

1819 SW 5th Ave #336

Portland OR 97201 US 503-251-3241 ggordon@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998