I. IDENTIFICATION INFORMATION 1. Theme: Bathymetric surface, Yakutat Bay Data set name: yak_bath 2. Originator: Interrain Pacific 3. Date: 2/15/97 4. Edition: 5. Description: This layer contains an interpolated bathymetric surface for Yakutat Bay, Alaska. This coverage interpolated from NOS bathymetric point data. Interrain Pacific augmented the NOS data with information from NOAA nautical charts for some areas of the outer coast. 6. Data Set Status: ___In preparation, Anticipated Completion_____ _X_Completed and operational ___On going; Update Frequency:____ Data Set Status Comments: 7. Geographic Coverage Description: This bathymetric layer covers Glacier Bay and Icy Strait from Excursion Inlet to Cape Spencer. Please check appropriate USGS 1:250,000 maps: ___Atlin ___Juneau _X_Mount Fairweather ___Port Alexander ___Skagway ___Sumdum _X_Yakutat 8. West Bounding Coordinate: 149 30 00 W 9. East Bounding Coordinate: 145 00 00 W 10. North Bounding Coordinate: 61 30 00 N 11. South Bounding Coordinate: 59 45 00 N 12. Theme keywords: _X_bathymetry _X_oceanography _X_shoreline 13. Access Restrictions: Data transfer costs will be based on staff time and media costs. 14. Use Restrictions: Data may not be sold. 15. Processing Information: Software used to automate: ARC/INFO Software Version: 7.x Hardware Platform: SUN Operating System used: UNIX File Name: bath_ln File Size: 73 mb Feature Type: ___Point (data point) ___Line (Arc) ___Polygon _X_Grid ___Text ___Other 16. Raster File Form ___ADRG ARC Digitized Raster Graphic (ARC/INFO GRID format) ___ADRI ARC Digitized Raster Imagery ___BIL Imagery, band interleaved by line ___BIP Imagery, band interleaved by pixel ___BSQ Imagery, band sequential ___DEM USGS Digital Elevation Model ___ERD74 ERDAS image files version 7.4 ___ERD81 ERDAS IMAGINE image files, ver8.1 ___GRAS3 GRASS (Geographic Resources Analysis Support System)v3 ___GRAS4 GRASS (Geographic Resources Analysis Support System) v4 ___IDL Interactive Data Language image file ___MOSS Multiple Overlay Statistical System export file ___TIFF Tagged Image File Format _X_Other Arc/Info Grid II. DATA QUALITY INFORMATION 1. Attribute Accuracy Explanation: General comparisons have been conducted between this coverage and NOAA nautical charts, and indicated reasonably good agreenment. During the processing of data from the NOS Hydrographic CD, we several many points with spurious data. Particular examples are points indicating a depth >0 where no land was present. The slope (bath_slp) layer was particularly useful in identifying spurious data. For the purpose of the bathymetric surface, all points with a positive depth (i.e. land) were deleted. This fixed most problems, but some may still exist. In addition, in areas without NOS surveys, we extracted points based no digital nautical charts. This helped complete the surface in a very general way, but are not as accurate as areas with formal NOS hydrographic data. 2. Attribute Accuracy: __________% __X__Unknown_____ _ _no accuracy assessment performed on dataset 3. Description of Data Completeness:. 4. Minimum Mapping Unit: _25m______________ _ __Unknown ____n/a 5. Positional Accuracy Comments: The NOS point data used to generate the gridded data includes data from many years. Positional accuracy of the point data is variable depending on the technology used to geo-reference. The depth and units of measurement for depth of the point data imply different levels of accuracy (i.e., 6 3/4 fathoms would likely have lower vertical accuracy than 63.4 meters). The number and position of points used to generate the gridded data is not known. The gridding process generalizes the point data. 6. Source Information: National Geophysical Data Center, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder CO 80303-3328 (303)497-6141. Contact person: Lt. Todd Bergren 7. Date of Source Data: VARIES 8. Scale of Source Data: >80% of all NOS Hydrographic survey points were within 25m of their nearest neighbor. 9. Data Processing Description: Point data was extracted from the NOS Hydrographic CD, and standardized into a consisten horizontal datum (NAD27). Interrain Pacific hand-digitized holes in the NOS data from NOAA digital nautical charts, and used ARC/INFO TIN routines to develop a surface interpolation. Subsequently, Interrain Pacific created a bathymetric grid based on the TIN representation of the combined bathymetric databases. III. SPATIAL DATA ORGANIZATION INFORMATION 1. Data Structure: ___point (x,y) ___vector(line >1 x,y) _X_raster (grid cell) ___tin (3 dimensional x,y,z) ___Other__________ 2. Raster File Row: 4278 3. Raster File Column: 4123 4. Raster File Vertical: 5. Raster File Number of Bytes per Pixel: 6. Raster file origin: X=373892.599, Y=6446838.998 IV. SPATIAL REFERENCE INFORMATION 1. Map Projection Name Projection: UTM Zone: 8 Datum: NAD27 Units: METERS Spheroid: Clarke1866 V. ENTITY AND ATTRIBUTE INFORMATION 1. Attribute Labels: VALUE indicated DEPTH in METERS 2. Attribute Definition Source: NOAA/NGDC E/GC3; 325 Broadway, Boulder CO 80303 (303) 479-6376 (Contact person: LT. Lee M. Cohen) VI. DISTRIBUTION INFORMATION 1. Distributor: Interrain Pacific 2. Distribution Liability: This information should NOT be used for navigation. Interrain Pacific makes no express or implied warranties with respect to the character, fitness, function, accuracy, or capabilities of the information presented or the appropriateness for any users purposes. In no event will Interrain Pacific be liable for any incidental, indirect, special, consequential or other damages suffered by the user of this information or other person. 3. Standard Order Process: Data will be provided on tape or CD-ROM based on a written request. 4. Hardware media type: 8mm tape, CD-ROM. 5. File Decompression Technique: None. 6. Decompressed Data Transfer Size: VII. METADATA REFERENCE INFORMATION 1. Metadata Date: March 3, 1997 2. Metadata Contact: Interrain Pacific VIII. CONTACT INFORMATION 1. Primary Contact Person: Interrain Pacific 2. Contact Mailing Address: 1200 NW Front Ave., Suite 470A Portland, OR 97209 3. Contact Voice Telephone: (503) 226-8108 4. Contact Facsimile Telephone: (503) 226-8110 5. Contact Electronic Mail Address: interrain@igc.apc.org