T-2856; Northern Part of Skagit Bay, Washington, 1908

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-2856; Northern Part of Skagit Bay, Washington, 1908

Geospatial_Data_Presentation_Form: map

Abstract:

Georeferenced United States Coast & Geodetic Survey Topographic Sheet T-2856; Northern Part of Skagit Bay, Washington, 1908; Scale: 1:20,000; Surveyor: Paul C. Whitney

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:  1908

Time_Period_Information:  1908

Single_Date/Time:

Calendar_Date: 1908

Currentness_Reference: 1908

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: 1908

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: 10 meters (using 12 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:

Out of numerous of possible benchmarks identified, 12 benchmark datasheets were located that matched benchmarks on the t-sheet that were monumented in 1907, prior to t-sheet production.  All of these benchmarks are located on the surveyed and detailed part of the sheet.  There are also benchmarks noted outside of the surveyed area, but those were not used because the accuracy of their surveyed locations is questionable and they were not needed.  The average benchmark error is 10.36 meters, which is good considering that this is a 1:20,000 scale t-sheet.

 

       Benchmark              PID    Date Mon.       LONG                 LAT               Measured distance between T-sheet benchmark & NGS-published benchmark     

1

ISLE

TR1277

1907

122 31 56.36571

48 22 16.46858

7.558367

2

STONE RESET

TR1290

1907

122 34 48.24351

48 22 26.65142

11.543396

3

EAST HOPE 2

TR1239

1907

122 33 39.75755

48 23 50.31480

8.860023

4

TONKON

TR1207

1907

122 32 34.75357

48 23 00.48715

9.50185

5

HOYPUS

TR1247

1907

122 36 32.16294

48 24 40.52144

5.647179

6

TIDE RESET

TR1208

1907

122 35 05.22123

48 25 36.93382

3.052279

7

GIB

TR1206

1907

122 34 41.92423

48 26 03.22209

9.341607

8

RIDGE

TR1192

1907

122 36 00.70654

48 25 57.19563

3.905125

9

END

TR1200

1907

122 33 16.66685

48 26 43.08809

23.677851

10

CRACK

TR1216

1907

122 33 17.16099

48 25 58.58949

21.321297

11

SUB

TR1193

1907

122 34 15.66937

48 25 10.17459

5.647179

12

KIKET

TR1230

1907

122 34 28.20262

48 25 02.39687

14.206073

 

           

Lineage:

Technician: Elizabeth Cassel  Date:  9-6-03

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:

 

Deception, 1854

Fidalgo l,1854

Allan, 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 1st 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

37

48

27

2

122

36

48

27

3

122

35

48

27

4

122

34

48

27

5

122

33

48

27

6

122

32

48

27

7

122

37

48

26

8

122

36

48

26

9

122

35

48

26

10

122

34

48

26

11

122

33

48

26

12

122

38

48

25

13

122

37

48

25

14

122

36

48

25

15

122

35

48

25

16

122

34

48

25

17

122

33

48

25

18

122

38

48

24

19

122

37

48

24

20

122

36

48

24

21

122

35

48

24

22

122

34

48

24

23

122

33

48

24

24

122

32

48

24

25

122

35

48

23

26

122

34

48

23

27

122

33

48

23

28

122

32

48

23

29

122

34

48

22

30

122

33

48

22

31

122

32

48

22

32

122

31

48

22

33

122

30

48

22

34

122

34

48

21

35

122

33

48

21

36

122

32

48

21

37

122

31

48

21

38

122

30

48

21

39

122

32

48

20

40

122

31

48

20

41

122

30

48

20

 

Not all of the ideal tic marks could be used for the initial resample, because they could not be identified on the t-sheet image.  Three different resamples were performed on this data.  The RMS errors were all below 0.003 after the first resample, but a few points had error distances from 5 to 8 meters.  First the point placement was readjusted on some points to account for the difficulty of seeing some tic marks on this sheet.  After point 6 (error = 7.5 m) was removed for the third resample, the RMS errors all dropped below 0.002 and error distances all dropped to near or below 5 meters, so this became the final resample.

 

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

 

 

 

 

 

 

 

 

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:

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:

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

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time