GRID BATHGRID67

Available as - [Outline] - [SGML]

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: E&S Chemistry
Publication_Date: 19971000
Title: GRID BATHGRID67
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 bathpt67. 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 sediment since the last century. Major sources include: ? 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. Bathymetric points collected in the 1867 survey were obtained from the U.S. Coast Survey Office. Data were derived from a paper map prepared by the U.S. Army Corps of Engineers. The coverage has 3750 points situated in an irregular network distributed throughout the bay and spaced approximately 200 to 300 m apart (Figure 1a). We noted that the x and y positional accuracy of the 1867 coverage appeared to have a shift when the outline of the bay was compared with the current bay outline (Figure 2). This was corrected using an affine coordinate transformation on twenty points located at locations presumed to be relatively stable on the shoreline of the bay. This transformation accounted for variability in scale, skewness, rotation and translation. The Root Mean Square Error of the transformation was 152 meters. The RMS error indicates how well the transformation matched the bay outline for all 20 data points across both data sets. It is a least square solution for the entire coverage. Several of the selected control points (i.e., Crab Harbor and one near McCoys Cove) may not have been as stable as we would like for this transformation. Excluding these points would only reduce the RMS error slightly. The transformed data set was used in the subsequent comparative analyses. The 1867 coverage also illustrated many landscape features which were not present in the 1957 and 1995 coverages due to revetment and other changes to the bay shoreline. Cape Meares Lake, Garibaldi, McCoys Cove, Larson Cove and the Jetty changed in the time period between 1867 and the more recent surveys due to construction activities and the spit breach. These areas were digitized and a new bay boundary coverage was prepared.

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:
FOR MORE DETAILED INFORMATION SEE TILLBATH.TXT
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 18670000
Currentness_Reference: Publication Date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None Planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -123.98551813
East_Bounding_Coordinate: -123.85875014
North_Bounding_Coordinate: 45.58738806
South_Bounding_Coordinate: 45.46764247
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: bathymetry
Theme_Keyword: surface
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: 1867
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: GRID BATHGRID57
Publication_Information:
Publication_Place: Corvallis,OR
Publisher: E&S Chemistry

Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Logical_Consistency_Report: Not applicable for raster data.
Completeness_Report: complete
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_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 errors associated with: 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 errors associated with: 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)
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: Interrain Pacific
Publication_Date: 19950000
Title: COVERAGE BATHPT67
Publication_Information:
Publication_Place: Portland,OR
Publisher: Interrain Pacific
Type_of_Source_Media: computer program
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 18670000
Source_Currentness_Reference: Publication Date
Source_Citation_Abbreviation: a
Source_Contribution: all (see Description in metadata for bathpt67)
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: Unknown

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell
Row_Count: 1414
Column_Count: 1025

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

BATHGRID67.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 14:41:09 1999