T-1873; Sheet No. 5, Topography of Gulf of Georgia, W T, Birch Bay to Boundary, 1888

Metadata:

Identification_Information
Data_Quality_Information
Spatial_Reference_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Puget Sound River History Project

Originator: Department of Earth & Space Sciences, University of Washington, Box 351310

Originator: Seattle, WA 98195

Publication_Date: 10/01/03

Title: T-1873; Sheet No. 5, Topography of Gulf of Georgia, W T, Birch Bay to Boundary, 1888

Geospatial_Data_Presentation_Form: map

Abstract:

Georeferenced United States Coast & Geodetic Survey Topographic Sheet T-1873; Sheet No. 5, Topography of Gulf of Georgia, W T, Birch Bay to Boundary, 1888; Scale: 1:10,000; Surveyor: J. J. Gilbert

Supplemental_Information: For a comprehensive historical and technical review of the production and interpretation of early Coast & Geodetic Survey T-sheets please refer to Shalowitz, A.L. 1964. Shore and Sea Boundaries, Volumes 2. U.S. Department of Commerce, U.S. Coast and Geodetic Survey, Washington, DC. This publication is available online at http://chartmaker.ncd.noaa.gov/hsd/shallow.htm

Time_Period_of_Content: 1888

Time_Period_Information: 1888

Single_Date/Time:

Calendar_Date: 1888

Currentness_Reference: 1888

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Keywords:

Theme:

Theme_Keyword: T-sheets

Theme_Keyword: Coastal Survey

Theme_Keyword: Land Cover

Theme_Keyword: Historical

Theme_Keyword: United States Coast and Geodetic Survey

Place:

Place_Keyword: Washington State

Place_Keyword: Puget Sound

Stratum:

Stratum_Keyword: Near Shore

Stratum_Keyword: Coast

Temporal:

Temporal_Keyword: 1888

Access_Constraints:

This georeferenced image may be freely downloaded and used. Please give credit to the Puget Sound River History Project, University of Washington.

http://riverhistory.ess.washington.edu

Use_Constraints:

This georeferenced image may be freely downloaded and used. Please give credit to the Puget Sound River History Project, University of Washington.

http://riverhistory.ess.washington.edu

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Brian Collins, Amir Sheikh

Contact_Organization:

Department of Earth and Space Sciences, University of Washington

Contact_Address:

Address_Type: mailing address

Address: Department of Earth and Space Sciences

Address: Box 351310

Address: University of Washington

City: Seattle

State_or_Province: WA

Postal_Code: 98195

Country: USA

Contact_Voice_Telephone: (206) 616-6584

Contact_Facsimile_Telephone: (206) 543-0489

Contact_Electronic_Mail_Address: bcollins@u.washington.edu

Contact_Electronic_Mail_Address: asheikh@u.washington.edu

Data_Quality_Information:

Positional_Accuracy:

Horizontal_Positional_Accuracy: 6 meters (using 6 reliable benchmarks)

To assess an independent check of the accuracy of the registration process, benchmarks located on the T-sheets were compared to published NGS benchmarks that were retraceable to the time of the surveyed T-sheet. (Published NGS benchmark information is located at http://www.ngs.noaa.gov/cgi-bin/datasheet.prl). Only benchmarks that could be established with a high degree of certainty that existed at the time of the original T-sheet survey and were not remounted were used in the final accuracy measurement. If no current benchmarks exist or if the benchmarks have been remounted in relation to the benchmarks on the T-sheet, hard points (areas that would expect little change since the original surveys) were used to give a general indicator of the T-sheet’s registration accuracy in lieu of a more rigorous method. Thus these hard point measurements must be viewed with some caution. It should be stressed that the accuracy assessment was to check the accuracy of the overall registration process, not necessarily the accuracy of the survey itself.

NOTE: Measured distances are rounded to the nearest meter. The hand-drawn representations of benchmarks on the T-sheets are often up to 10 meters in width. To assess an independent check of the accuracy of the registration process, the measured distance is from the NGS-published coordinates to the perceived middle of the benchmark depicted on the T-sheet. In addition, the overall shape of the benchmark symbol is sometimes obscured by other symbology on the T-sheet. Thus, there is a certain level of uncertainty introduced due to the ambiguous location of the benchmark on the T-sheet.

Horizontal_Positional_Accuracy_Report:

Seven benchmarks were identified on the t-sheet that had corresponding NGS datasheets. BIRCH POINT, CREEK, DRAYTON I, and TRAP were all monumented prior to t-sheet production. SEMIAHMOO LIGHTHOUSE was updated on the t-sheet in 1905, and BOUNDARY was monumented prior to observation in 1905, to mark the US/Canadian border. BARTON 1858 appear on the t-sheet and in the NGS datasheets, but it is unclear where the exact benchmark is noted on the t-sheet, so this point could not be used in the error assessment. So the following six benchmarks were used for the error assessment, giving an average horizontal positional accuracy of 5.64 meters.

	Station Name	PID	Date Mon/Obs	Current Survey Control NAD83 Longitude Latitude		Error Distance*
	Station Name	PID	Date Mon/Obs	Current Survey Control NAD83 Longitude Latitude		Error Distance*
1	BARTON 1858	TR2153	UNK	122 47 32.86752	48 55 55.14985	-
2	BIRCH POINT 1858	TR2156	1858	122 49 19.55533	48 56 30.37315	9.03125
3	CREEK	TR2582	1888	122 44 03.80409	48 57 48.56037	4.11279
4	DRAYTON I	TR2583	1888	122 47 21.49162	48 58 48.10052	5.767636
5	TRAP	TR2663	1888	122 45 57.12431	48 57 49.74333	5.626736
7	SEMIAHMOO LIGHTHOUSE IBC	TR2152	OBS 1905	122 47 02.68363	48 59 32.26665	2.310176
11	BOUNDARY MON 5 CD US	TR0620	1905	122 45 26.16551	49 00 07.52163	7.010107

*Measured distance between T-sheet benchmark & NGS-published benchmark

Lineage:

Technician: Elizabeth Cassel

Date: 11-18-03

Process_Step:

Process_Description: The georeferencing of T-sheets in the Puget Sound region was funded by the Puget Sound Nearshore Project (PSNERP) http://www.pugetsoundnearshore.org/

Scanned images were obtained from Information Manufacturing Corporation, 7000 Infantry Ridge Road, Suite 200, Manassas, VA 20109 Phone: (703) 393-6866.

The methodology used to georeference the T-sheets was modified from the previous work of Jennifer Burke (NOAA) in the Lower Columbia and Daniels et al (2001). The georeferencing and error assessment process were carried out using Erdas Imagine 8.6 and ArcGIS 8.3. For additional information concerning the georeferencing method please refer to: http://rocky2.ess.washington.edu/riverhistory/tsheets.php

Datum Shift:

Most T-sheets do not have a current datum represented on them (i.e. NAD 27, NAD 83). Graticules (tics) marking Latitude and Longitude in the early local Puget Sound Datum (PSD) and a later update to North American Datum (NAD) projection are most often present. To calculate the X, Y shift from NAD to NAD 27, X and Y values were used from datum difference tables for survey stations around most of Puget Sound (Patton, 1999). An overall datum shift was determined for the area covered by the T-sheet by averaging the shift from a number of survey stations in or nearby that area represented on the T-sheet.

The following survey stations were used to calculate the datum shift:

Blaine, 1888

Blaine Bdg. Mon. No. 5, 1905

Semiamos H'br. L. H. 1905

Creek, 1888

Trap, 1888

Drayton 1, 1858

Registration:

For georeferencing, tics were used only surrounding areas that depicted nearshore features on the T-sheet. This was mainly done to hasten the overall process due to the magnitude of the scope of the project while maintaining the best control around areas of interest. The sheets were then rectified using a 1^st order polynomial transformation. Points that produced relatively high RMS values, as well as tic points that consistently fell outside of 4.5 meters (on a 1:10,000 scale T-sheet) of their projected UTM coordinates were omitted.

The following tic marks were used for georeferencing the initial resample:

	Longitude		Latitude
	deg	min	deg	min
1	122	47	49	0
2	122	46	49	0
3	122	45	49	0
4	122	44	49	0
5	122	48	48	59
6	122	47	48	59
7	122	46	48	59
8	122	45	48	59
9	122	44	48	59
10	122	43	48	59
11	122	42	48	59
12	122	49	48	58
13	122	48	48	58
14	122	47	48	58
15	122	46	48	58
16	122	45	48	58
17	122	44	48	58
18	122	43	48	58
19	122	42	48	58
20	122	50	48	57
21	122	49	48	57
22	122	48	48	57
23	122	47	48	57
24	122	46	48	57
25	122	45	48	57
26	122	44	48	57
27	122	43	48	57
28	122	49	48	56
29	122	48	48	56
30	122	47	48	56
31	122	46	48	56
32	122	45	48	56
33	122	48	48	55
34	122	47	48	55
35	122	46	48	55

Three resamples were performed on this data. After the first resample, points 1, 3, 5, 12, 27, 28, and 35 had high RMS errors and high error distances, so points12, 28, and 35 were removed. This improved the errors of points 1 and 5. For the final resample, points, 3, 12, 27, 28, and 35 were removed, leaving the rest of the points with error distances under 5 meters, and RMS errors below 0.003.

Several factors that can introduce error into the registration process include:

The accuracy of the graticules and projection lines drawn on the map.

Non-uniform shrinkage of the original map due to age and storage conditions.

Distortion caused by the scanning process.

Loss of resolution and distortion due to image compression.

Ability of the technician to identify appropriate survey stations that correspond to the area of the T-sheet to compute the datum shift.

Ability of the technician to identify and locate appropriate tics on the T-sheet for the transformation.

The geometric transformation method employed.

References:

Daniels, R. C. and R.H. Huxford. 2001. An error assessment of vector data derived from scanned National Ocean Service topographic sheets. Journal of Coastal Research 17: 611 – 619.

Patton, R.S., 1999. Datum Differences: Atlantic, Gulf, and Pacific Coast of the United States. U.S. Department of Commerce, U.S. Coast and Geodetic Survey, Washington D.C. (Original publication: 1936)

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: Universal Transverse Mercator

Universal_Transverse_Mercator:

UTM_Zone_Number: 10

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.999600

Longitude_of_Central_Meridian: -123.000000

Latitude_of_Projection_Origin: 0.000000

False_Easting: 500000.000000

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row and column

Coordinate_Representation:

Abscissa_Resolution: 3.000000

Ordinate_Resolution: 3.000000

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Distribution_Information:

Resource_Description: Downloadable Data

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Metadata_Reference_Information:

Metadata_Date: 20020723

Metadata_Contact: