San Francisco Bay Area, California, Nautical Chart, 1877 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Entrance to San Francisco Bay, California, from a trigonometrical survey under the direction of A.D. Bache, Superintendent of the Survey of the Coast of the United States ; triangulation by R.D. Cutts, asst. & A.F. Rodgers, sub-asst. ; topography by R.D. Cutts, asst., A.M. Harrison & A.F. Rodgers, sub-assts. ; hydrography by the party under the command of Lieut. Comdg. James Alden, U.S.N. assist. It was published by The Survey in 1877. Scale 1:50,000. Covers the San Francisco Bay Area. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows coastal features such as lighthouses, buoys, beacons, rocks, channels, points, coves, islands, bottom soil types, wharves, and more. Includes also selected land features such as roads, railroads, drainage, land cover, selected buildings, towns, and more. Relief shown by hachures and spot heights; depths by sounding, shading, and contours. Includes inset map: Sub-sketch of entrance to San Francisco Bay (Scale 1:400,000), and inset views: View of the entrance to San Francisco Bay, Alcatraz N.E. by E. 1/2 (by compass 10 miles) -- View of the entrance to San Francisco Bay from Yerba Buena Id. -- View of the entrance to San Pablo Bay from near Angel Id. Also includes text and tables. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Historic paper maps can provide an excellent view of the changes that have occurred in the cultural and physical landscape. The wide range of information provided on these maps make them useful in the study of historic geography, and urban and rural land use change. As this map has been georeferenced, it can be used in a GIS as a source or background layer in conjunction with other GIS data.

source map publication date.

map.

None.

The georeferenced raster is a faithfully reproduced digital image of the original source map. Some differences may be detected between the source graphic used and the raster image due to the RGB values assigned that particular color. The intent is to recreate those colors as near as possible. Data completeness for raster digital image files reflect content of the source graphic. Features may have been eliminated or generalized on the source graphic due to scale and legibility constraints The horizontal positional accuracy of a raster image is approximately the same as the accuracy of the published source map. The lack of a greater accuracy is largely the result of the inaccuracies with the original measurements and possible distortions in the original paper map document. There may also be errors introduced during the digitizing and georeferencing process. In most cases, errors in the raster image are small compared with sources of error in the original map graphic. The RMS error for this map is 114.02878 feet. This value describes how consistent the transformation is between the different control points (links). The RMS error is only an assessment of the accuracy of the transformation.

ESRI ArcCatalog 9.2.

Not applicable.