GRID BATHGRID57

Available as - [Outline] - [SGML]

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: E&S Chemistry
Publication_Date: 19971000
Title: GRID BATHGRID57
Geospatial_Data_Presentation_Form: map
Publication_Information:
Publication_Place: Corvallis,OR
Publisher: E&S Chemistry
Online_Linkage: <http://www.orst.edu/dept/tbaynep/active.html>
Description:
Abstract:
Bathymetric surface grid derived from bathpt57. Several studies of sedimentation and sediment composition have been conducted in Tillamook Bay (e.g., Avolio 1973, Glenn 1978, Komar 1997). The latter report provides an overview of what is known about sedimentation of the bay, which is an important environmental concern because of its influence on habitat quality and navigation. Bathymetric surveys were conducted in 1867, 1957, and 1994/1995. E&S performed a comparative analysis for TBNEP of the available historical bathymetric data sets for the bay. The objective of this analysis was to quantify, to the extent possible, the changes in bathymetry that occurred between the times of the available surveys. It is considered likely that the bay has received excessive contributions of ? the breach of Bayocean Spit between 1952 and 1956 ? deforestation in the watershed ? the Tillamook Burns of 1933, 1939, 1945, and 1951 ? land use practices in the watershed, including road construction, agriculture, and urbanization The greatest impacts of these sources of sedimentation probably occurred prior to the 1957 bathymetric survey. In addition, the bay has been altered in a variety of other ways that have undoubtedly affected its bathymetry. These include the drainage of wetlands and construction of dikes and levees. The inlet from the ocean was modified by constructing jetties, and dredging of navigation channels has occurred throughout this century (Percy et al. 1974). The most catastrophic change occurred in 1952 when the spit was breached just north of the current location of Cape Meares Lake. This may have been due to erosion of Bayocean spit in response to construction of the north jetty. The breach remained open until a dike was constructed in 1956 to close it off.

Purpose:
We developed bathymetric maps for each of the data sets in a consistent fashion. This allowed direct comparison between surveys to permit quantification of the changes that occurred in the depth of the bay during the intervening periods. Several studies of sedimentation and sediment composition have been conducted in Tillamook Bay (e.g., Avolio 1973, Glenn 1978, Komar 1997). The latter report provides an overview of what is known about sedimentation of the bay, which is an important environmental concern because of its influence on habitat quality and navigation. Bathymetric surveys were conducted in 1867, 1957, and 1994/1995. E&S performed a comparative analysis for TBNEP of the available historical bathymetric data sets for the bay. The objective of this analysis was to quantify, to the extent possible, the changes in bathymetry that occurred between the times of the available surveys. FOR MORE DETAILED INFORMATION SEE TILLBATH.TXT
Supplemental_Information:
Much of this documentation was extracted from "BATHYMETRIC ANALYSIS OF TILLAMOOK BAY Comparison Among Bathymetric Databases Collected in 1867, 1957 and 1995"

by

Joseph A. Bernert and Timothy J. Sullivan see Tillbath.doc for more detail.

Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 19570700
Currentness_Reference: source data
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None Planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -123.96617779
East_Bounding_Coordinate: -123.85813604
North_Bounding_Coordinate: 45.57333077
South_Bounding_Coordinate: 45.45561705
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: Transportation
Theme_Keyword: Environmental monitoring
Theme_Keyword: Watershed management
Theme_Keyword: Sedimentation
Theme_Keyword: Freshwater ecosystems
Theme_Keyword: Sediment transport
Theme_Keyword: Surface waters
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: North America
Place_Keyword: United States of America
Place_Keyword: OR
Place_Keyword: Oregon
Place_Keyword: Tillamook Bay
Temporal:
Temporal_Keyword_Thesaurus: None
Temporal_Keyword: historical
Temporal_Keyword: 1957
Access_Constraints: none
Use_Constraints: see Distribution_Liability
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Joe Bernert or Tim Sullivan
Contact_Organization: E&S Chemistry
Contact_Address:
Address_Type: Mailing and Physical Address
Address: P.O. Box 609
City: Corvallis
State_or_Province: OR
Postal_Code: 97339
Country: USA
Contact_Voice_Telephone: (541) 758-6305
Contact_Electronic_Mail_Address: unknown
Native_Data_Set_Environment:
Windows_NT, 4.0, Intel ARC/INFO version 7.2.1
Cross_Reference:
Citation_Information:
Originator: E&S Chemistry
Publication_Date: 19971000
Title: COVERAGE BATHGRID95
Geospatial_Data_Presentation_Form: ARCINFO GRID
Series_Information:
Series_Name:
Issue_Identification:
Publication_Information:
Publication_Place: Portland, OR
Publisher: E&S Chemistry
Online_Linkage:

Data_Quality_Information:
Logical_Consistency_Report: Not applicable for raster data.
Completeness_Report: complete
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The variance associated with the 1957 bathymetric surface illustrates the unfortunate nature of this survey. The spacing of data points along the horizontal survey transects was much less than the spacing between transects. Thus, the variance is low in strips across the bay that lie about each of the transects The variance between transects is high (> 10 ft).The range (r) of the semivariogram for 1867 was 584 m, as compared with 271 m in 1957 and 481 m in 1995 .Other potential sources of error in the bathymetric maps include
1.positional accuracy of the collected data,
2.depth measurements,
3.data entry and processing,
4.changing scale between and within data sets,
and
5.the density and spatial configuration of the
data points (Burroughs 1986).
(see metadata for bathpt67)
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The range (r) of the semivariogram for 1867 was 584 m, as compared with 271 m in 1957 and 481 m in 1995 .Other potential sources of error in the bathymetric maps include
1.positional accuracy of the collected data,
2.depth measurements,
3.data entry and processing,
4.changing scale between and within data sets,
and
5.the density and spatial configuration of the
data points (Burroughs 1986).
(see metadata for bathpt57)
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Interrain Pacific
Publication_Date: 19950000
Title: COVERAGE BATHPT57
Publication_Information:
Publication_Place: Portland,OR
Publisher: Interrain Pacific
Type_of_Source_Media: computer program
Source_Citation_Abbreviation: a
Source_Contribution: all
Process_Step:
Process_Description:
The bathymetric coverages were developed by interpolating surfaces from the survey data points. Many different interpolation techniques exist for generating surfaces from point measurements. We chose to use ordinary kriging because it is well suited to irregularly spaced data, is custom fit with a geostatistical model, and allows for calculation of variance associated with the interpolation. Kriging is one of the most common geostatistical methods for interpolating point data into three-dimensional surfaces. It is a least squares prediction method that includes a spline interpolation (Jernigan, 1986), and it assumes that the spatial variability in a surface is statistically homogeneous throughout the data. Kriging calculates a weighted moving average equation which estimates the true value of a regionalized variable and site specific location (Deutsch and Journel 1992, Cressie 1991). In order to perform kriging, the spatial correlation structure of the data needs to be assessed. A variogram model provides the interpretation of the correlation structure of the data (Englund and Sparks 1988). The variogram is used to evaluate the spatial correlation of data points in the data base (Webster and Oliver 1990). This is determined by representing the correlation among sample points separated by specific distances (y(h)). The model was fitted interactively and graphical examination of the semivariogram assisted in determining a good model fit (Jernigan 1986). A Gaussian distribution was chosen to fit the model to the data. FOR MORE DETAILED INFORMATION SEE TILLBATH.TXT
Process_Date: 19971000

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell
Row_Count: 1396
Column_Count: 866

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Lambert Conformal Conic
Lambert_Conformal_Conic:
Standard_Parallel: 43
Standard_Parallel: 45.5
Longitude_of_Central_Meridian: -120.5
Latitude_of_Projection_Origin: 41.75
False_Easting: 400000.00000
False_Northing: 0.00000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 30.0
Ordinate_Resolution: 30.0
Planar_Distance_Units: 3.2808400000
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: GRS1980
Semi-major_Axis: 6378206.4
Denominator_of_Flattening_Ratio: 294.98

Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
depth VALUE in feet

BATHGRID57.VAT

COLUMN   ITEM NAME        WIDTH OUTPUT  TYPE N.DEC
    1  VALUE                  4    10     B      -
    5  COUNT                  4    10     B      -


Entity_and_Attribute_Detail_Citation: not available

Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Tillamook Coastal Watershed Resource Center
Contact_Position: G.I.S. Coordinator
Contact_Address:
Address_Type: mailing and physical address
Address: 6385 Tillamook Ave.
City: Bay City
State_or_Province: OR
Postal_Code: 97107
Country: USA
Contact_Voice_Telephone: (503)377-4000
Contact_Electronic_Mail_Address: requests@tcwrc.tbcc.cc.or.us
Contact_Instructions: Contact via email,mail,fax or telephone
Distribution_Liability:
no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The Tillamook Coastal Watershed Resource Center shall not be held liable for improper or incorrect use of the data described and/or contained herein.

Metadata_Reference_Information:
Metadata_Date: 19981215
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Tillamook Coastal Watershed Resource Center
Contact_Person: Ann Stark
Contact_Position: GIS Coordinator
Contact_Address:
Address_Type: mailing and physical address
Address: 6385 Tillamook Ave.
City: Bay City
State_or_Province: OR
Postal_Code: 97107
Country: USA
Contact_Voice_Telephone: (503)377-4000
Contact_Facsimile_Telephone: (503)377-4010
Contact_Electronic_Mail_Address: requests@tcwrc.tbcc.cc.or.us
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Access_Constraints: none
Metadata_Use_Constraints: none

Generated by mp version 2.4.10 on Wed Jul 28 14:40:48 1999