T-2301; Washington Sound, Part of San Juan Island, Pear Point to Eagle Point, Washington, 1897

Metadata:

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-2301; Washington Sound, Part of San Juan Island, Pear Point to Eagle Point, Washington, 1897

Geospatial_Data_Presentation_Form: map

Abstract:

Georeferenced United States Coast & Geodetic Survey Topographic Sheet T-2301; Washington Sound, Part of San Juan Island, Pear Point to Eagle Point, Washington, 1897; 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: 1897

Time_Period_Information: 1897

Single_Date/Time:

Calendar_Date: 1897

Currentness_Reference: 1897

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: 1897

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: 5 meters (using 11 reliable benchmark)

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:

Of the sixteen benchmarks noted on this t-sheet twelve datasheets were found. One of these datasheets was for a lighthouse visible on the t-sheet but monumented in 1940 – the nearby benchmark as noted on the t-sheet did not have a datasheet. The others were all monumented in 1897 – the same year as the mapping. The overall average difference in location was 5.1 meters, and the average for the eleven was 4.9 meters.

Station Name	PID	Current Survey Control NAD83		Distance From Tsheet, using NEAR
Station Name		Current Survey Control NAD83		Distance From Tsheet, using NEAR
		Long	Lat
PEAR RESET	TR2079	122 58 57.59687	48 30 52.72732	4.4
LITTLE ISLAND RESET	TR2223	123 00 47.65871	48 31 05.61167	1.8
DINNER ISLAND RESET	TR2218	123 00 29.65353	48 30 26.39827	3.9
ARGYLE RESET	TR2212	123 00 57.69972	48 30 21.31633	4.6
TOM RESET	TR2337	123 01 05.39481	48 29 47.42329	6
LOW POINT RESET	TR2334	123 00 27.52334	48 29 03.32995	8.2
HARBOR ROCK RESET	TR1808	122 58 13.89483	48 28 11.51175	3.4
AVENUE RESET	TR1801	122 57 36.25039	48 27 52.18728	12.2
TRAP RESET	TR1803	122 57 25.48223	48 27 28.93707	1
CATTLE POINT LIGHT	TR1802	122 57 47.99819	48 27 02.30612	7.3
SAN JUAN	TR2335	123 02 13.18200	48 27 36.26808	2.6
FORT RESET	TR2338	123 00 56.48933	48 27 47.26337	6.3

Lineage:

Technician: Joanna Marsolek Date: 9-23-03

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 University of Washington Libraries at http://www.wsulibs.wsu.edu/holland/masc/sanjuanindex.html

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:

San Juan, 1867

Bellevue, 1854

James North, 1854

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	123	3	48	32
2	123	2	48	32
3	123	1	48	32
4	123	0	48	32
5	122	59	48	32
6	122	58	48	32
7	123	3	48	31
8	123	2	48	31
9	123	1	48	31
10	123	0	48	31
11	122	59	48	31
12	122	58	48	31
13	123	3	48	30
14	123	2	48	30
15	123	1	48	30
16	123	0	48	30
17	122	59	48	30
18	122	58	48	30
19	123	2	48	29
20	123	1	48	29
21	123	0	48	29
22	122	59	48	29
23	122	58	48	29
24	122	57	48	29
25	123	2	48	28
26	123	1	48	28
27	123	0	48	28
28	122	59	48	28
29	122	58	48	28
30	122	57	48	28
31	123	2	48	27
32	123	1	48	27
33	123	0	48	27
34	122	59	48	27
35	122	58	48	27
36	122	57	48	27
37	123	2	48	26
38	123	1	48	26
39	123	0	48	26
40	122	59	48	26
41	122	58	48	26
42	122	57	48	26

Two resamples were performed on this data. The overall RMS was 0.0595 and individual RMS ranged from 0.04 to 0.12. Relative to the RMS for the majority of tiffs these values are significantly higher. This is because the tiffs covering the San Juan Islands have come from sid files and have a much higher resolution. The RMS values are expressed in pixels. Two points, 2 and 3, that had RMS values among the highest and that were well outside mapping extent were removed. This did not improve individual RMS values significantly, but because overall RMS was reduced this resample was maintained for the final tiff.

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: 2.000000

Ordinate_Resolution: 2.000000

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1927

Ellipsoid_Name: Clarke 1866

Semi-major_Axis: 6378206.400000

Denominator_of_Flattening_Ratio: 294.978698

Distribution_Information:

Resource_Description: Downloadable Data

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Transfer_Size: 24.630

Metadata_Reference_Information:

Metadata_Date: 20020723

Metadata_Contact: