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.eduUse_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.eduPoint_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
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
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