Online Links:
To provide a digital topographic map of the San Francisco Bay region to the public.
1. Composite of the culture, culture-names, land net and primary roads 2. Composite of the drainage and drainage names 3. Composite of intermediate and index contours 4. Secondary roadsScanning was done on a Scitex R280 at a resolution of 20 points/millimeter (508 dpi). The Scitex R280 was used to edit the raster scans and to separate the index and intermediate contours into separate coverages. The raster scans were then vectorized on the Scitex R280 with a curvetype of 1 and a tolerance of 1. The vectorization process distorts characters representing letters and numbers, as well as some other symbols, rendering them unreadable in some instances. The vectorized scans were imported into ARC/INFO using the SCITEXLINE command. ARC/INFO was used to modify edge joins, and to remove duplicate names (in adjacent sheets) and marginal information (to allow for mosaicing of adjacent sheets). Each file was converted from digitizer inches to UTM meters using latitude/longitude intersections on the scanned separates as reference points.
Are there legal restrictions on access or use of the data?Access_Constraints: none
Use_Constraints: none
This report is preliminary and has not been reviewed for conformity with U. S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U. S. Government.
This database, identified as "A digital version of the 1970 U.S. Geological Survey topographic map of the San Francisco Bay Region, three sheets, 1:125,000," has been approved for release and publication by the Director of the USGS. Although this database has been reviewed and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. This database is released on condition that neither the USGS nor the U. S. Government may be held liable for any damages resulting from its use.
| Data format: |
ARC/INFO coverage Description of coverage Sheet 1 (sht1.tar.gz) sh1c.e00 Culture sh1d.e00 Drainage sh1ir.e00 Intermediate contours sh1ix.e00 Index contours sh1r.e00 Roadsin format ARCE (version 7.x) Size: 9 |
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| Network links: |
http://pubs.usgs.gov/of/1997/of97-500/sht1.tar.gz |
| Data format: |
ARC/INFO coverage Description of coverage Sheet 2 (sht2.tar.gz) sh2c.e00 Culture sh2d.e00 Drainage sh2ir.e00 Intermediate contours sh2ix.e00 Index contours sh2r.e00 Roadsin format ARCE (version 7.x) Size: 18.3 |
|---|---|
| Network links: |
http://pubs.usgs.gov/of/1997/of97-500/sht2.tar.gz |
| Data format: |
ARC/INFO coverage Description of coverage Sheet 3 (sht3.tar.gz) sh3c.e00 Culture sh3d.e00 Drainage sh3ir.e00 Intermediate contours sh3ix.e00 Index contours sh3r.e00 Roadsin format ARCE (version 7.x) Size: 24.3 |
|---|---|
| Network links: |
http://pubs.usgs.gov/of/1997/of97-500/sht3.tar.gz |