Slides were taken of any headwater stream shown on the USGS map within the specified sites. The slides were projected onto the aerial photo at the appropriate scale, and the headwater stream locations were drawn on the aerial photo. Attachment B lists site and aerial photo numbers, and notes locations where streams were mapped onto aerial photos. Aerial photo distortion. This distortion originates from the lenses used for the original photograph and the enlargement, and from stretching or shrinking which occurs during the printing of the photo.
Distortion typically is greatest near the edges of photos.
Assessor's map drafting inaccuracy. Assessor's maps often do not align well with each other, nor with aerial photo locations of roads and property lines. Assessor's map copying distortion. Photocopied maps are typically smaller than what labeled dimensions indicate their actual size to be. GIS map inaccuracy.