Año Nuevo to Santa Cruz, California –A Photographic Tour of the Coastline
by Henry Chezar and Florence L. Wong
U.S. Geological Survey Digital Data Series DDS-61
Version 1.0
Note: The interactive maps do not seem to work with Firefox; use Internet Explorer or Safari instead.
Introduction
From 1995 to 1999 the United States Geological Surveyconducted a multifaceted scientific study of theseafloor geology and geologic processes within theMonterey Bay National Marine Sanctuary. Included in thisstudy and presented here is a digital photographic surveydocumenting the coastal morphology and stratigraphy between Point AñoNuevo and Santa Cruz, California, with precision-navigated overlappingimages. Another part of the study is producing a digitaldatabase of seafloor geologic maps. A comparison of thenewly acquired seafloor maps and coastline images provides ameans of visualizing the transition from sea to land.
The more than 500 digital coastline images included onthis CD-ROM are linked by interactive location maps. TheHTML and image files are also accessible by standardbrowser and image software.
Photographic Method
The sea-level images of the coast were collected fromaboard the research vessel RV David Johnston onNovember 4, 1998. We motored from Año Nuevo southward to Santa Cruz at an average speed of 12 knots (22km/hr) and acquired more than 500 overlapping,high-resolution digital images. Each photograph encompassesapproximately 200 m of coastline depending on the distancefrom shore. Overlaps between adjacent photographs aretens of meters.
The photographs were taken with a 35-mm high-resolutiondigital camera connected to a portable global positioningsystem (GPS) receiver with a horizontal accuracy of lessthan 3 meters. For most of the images, the GPS data (date,time of day, latitude, longitude, and altitude) arerecorded in the upper left corner of the image. The GPSdata are of the ship positions only and are best read onthe higher-resolution (300 dpi) images. Because of therapid camera firing rates needed to acquire overlappingimages, the GPS information would sometimes be missing,duplicated or erroneous because of inadequate satellitedownload time. In those situations, an interpolatedposition is inserted in the sequence log (photolog.txt).As all images were taken at sea level, the altitude data oneach image should be ignored.
The images were captured in Kodak compressed TIFF format.Each image, when uncompressed with Kodak software, has afile size of 4.5 Mb (megabytes). To fit all the images onone CD-ROM, each TIFF file was desampled and converted to ahigh-quality JPEG (xxx.jpg) image that is just under 1 Mbin size (300 dots per inch at 3 x 5 inch). A second set ofimages was desampled to about 30 to 50 kb (72 dots per inchat 4 x 5 inch) for more rapid viewing.View the Images
The images are linked to a series oflocation maps. The hierarchy of links looks likethis:
Regional map (92 kb)
Detailed map (window x)
72 dpi image
300 dpi image
The regional map displays the 23 areas into which thephotographic images were divided. Each number on theregional map is a link to a detailed map (for example,window 8) that includes a sequence of about 30 images withan overlap of 5 images (for example, windows 8 and 9 have 5images in common). Each of the points on a detailed map islinked to a 72 dpi version of the image captured at thatlocation. Along with each 72 dpi image another link willdisplay the higher-resolution 300 dpi image.
Use the Images
The maps and images may be viewed directly with commonlyavailable browser and image software. To use an image inanother application, use the "Save image as" feature ofyour browser or go directly to the image files. The imagesand other files are arranged in folders or directories onthis CD-ROM as follows:
Quick Start