Resolution: 1.0 Meter

Band: 1-band: Panchromatic

USDA Agricultural Adjustment AdministrationBlack and WhiteScanned and georectified using ERDAS ImagineFlying height 40,000 feet, 6-inch focal length cameraScale: 1:20,000SRS: NAD83 HARN Delaware State Plane meters

These are scanned images from aerial photography flow in 1937/38 by the Agricultural Stabilization and Conservation Service, maintained by the National Archives. These images are presented as individual tiles, county-wide and state-wide mosaics. Initial purpose was to provide base for digitizing Historic Forest Cover in Delaware. The data set could be used for other similar change analyses.

1. Heads-up digitizing was used to create ground control points on the 1937 Images using the 1997 Imagery as a reference. Every attempt was made to create GCPs at a standard scale of 1:3,000, however, due to photo quality this was not always possible. The scanned images were then registered to those points. The ground control points were stored for each image tile along with the RMS error from the registration process. See the included tutorial file for more detail on the registration process. This document was used for training and reference by staff members doing the processing. 2. Registered images (1937 Corrected) were subsetted (i.e. cropped) to remove photograph borders, fiducial marks, and distorted edges. 3. Image subsets (1937 Sub) were grouped together by county and combined into image mosaics.

Resolution: 1.0 Meter

Band: 1-band: Panchromatic

USDA Agricultural Adjustment AdministrationBlack and WhiteScanned and georectified using ERDAS ImagineFlying height 40,000 feet, 6-inch focal length cameraScale: 1:20,000SRS: NAD83 HARN Delaware State Plane meters

These are scanned images from aerial photography flow in 1937/38 by the Agricultural Stabilization and Conservation Service, maintained by the National Archives. These images are presented as individual tiles, county-wide and state-wide mosaics. Initial purpose was to provide base for digitizing Historic Forest Cover in Delaware. The data set could be used for other similar change analyses.

1. Heads-up digitizing was used to create ground control points on the 1937 Images using the 1997 Imagery as a reference. Every attempt was made to create GCPs at a standard scale of 1:3,000, however, due to photo quality this was not always possible. The scanned images were then registered to those points. The ground control points were stored for each image tile along with the RMS error from the registration process. See the included tutorial file for more detail on the registration process. This document was used for training and reference by staff members doing the processing. 2. Registered images (1937 Corrected) were subsetted (i.e. cropped) to remove photograph borders, fiducial marks, and distorted edges. 3. Image subsets (1937 Sub) were grouped together by county and combined into image mosaics.