River Bathymetry (1888) | ||||||
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| Category | Hydro | |||||
| Feature Dataset Name | Stand-Alone | |||||
| Item Name | river_depth_1888_pdx | |||||
| Database Type | SDE | |||||
| Originator | City of Portland | |||||
| Bureau | Bureau of Planning and Sustainability | |||||
| Publication Date | 04/02/2020 | |||||
| Abstract | Willamette River 1888 and 1895 depth polygons (from Willamette Falls to the Columbia) derived from TIN model of river bathymetry. Original reference points and breaklines digitized and interpolated by the City of Portland, Bureau of Planning, from United States Coast & Geodetic Survey 1888 Columbia River chart (Fales Landing to Portland) and U.S. Army Corps of Engineers 1895 surveys of the Upper Willamette (Sheets 14 and 15). NOTE: Other data such as streams, wetlands, and off-channel waterbodies were also digitized from the historic Willamette River maps. Please contact the City of Portland, Bureau of Planning using the contact information below if you are interested in aquiring this information. | |||||
| Purpose | For viewing and analyizing depths of the historic Willamette River. | |||||
| Supplemental Information | Because of the quality and number of historic depth sounding points is relatively low (compared to modern surveys,) there is a greater degree of uncertainty regarding this historic data. The majority of errors would involve an overestimation of shallow areas (because the model assumes shallow if no information is available.) A methodology was developed which attempts to limit this error, but any public disclosure of raw numbers should be qualified. Sources: 1888 chart - NOAA Historical Map & Cahart Collection http://anchor.ncd.noaa.gov/states/or.htm] 1895 charts - Oregon Historical Society (1200 SW Park Avenue, Portland, OR 97205) | |||||
| Last Dataset Update | 01/01/1900 00:00 | |||||
| Last Source Update | 01/01/1900 00:00 | |||||
| Maintenance/Update Frequency | None planned | |||||
| Extent | Clackamas County, Multnomah County, and Washington County, Oregon | |||||
| Data Type | Vector | |||||
| Shape Type | Polygon | |||||
| Feature Count | 772 | |||||
| Horizontal Position Accuracy | Reference Data Registration Information: Transformation: 1st Order Polynomial Total 1888 RMS: 57.61' Total 1895 RMS (sheet 15): 28.65' Total 1895 RMS (sheet 14): 40.35' Horizontal registration error due to limited and/or inconsistent registration points (1888 to 2001) | |||||
| Horizontal Position Accuracy Link | Neither | |||||
| Progress | Complete | |||||
| North Bounding Coordinate | 737243.562664047 | |||||
| South Bounding Coordinate | 654759.687664047 | |||||
| East Bounding Coordinate | 7652207 | |||||
| West Bounding Coordinate | 7609372 | |||||
| Theme Keyword(s) | Willamette River, bathymetry, river depths, historic channel | |||||
| Theme Keyword Thesaurus | None | |||||
| Place Keyword(s) | Portland, Multnomah County, Washington County, Clackamas County, Oregon | |||||
| Place Keyword Thesaurus | None | |||||
| Access Constraints | Available for Public Use | |||||
| Use Constraints | These data are distributed under the terms of the City of Portland Data Distribution Policy. Care was taken in the creation of this data but it is provided "as is". The City of Portland cannot accept any responsibility for errors, omissions, or positional accuracy. | |||||
| Source Dataset Type | Enterprise Geodatabase | |||||
| Output Geodatabase | EGH_Public | |||||
| Distribution | Grid: State plane coordinate system 1983(91). Units: International feet Datum: North American Datum of 1983/1991 (HPGN) Liability: The information in this file was derived from digital databases on the City of Portland GIS. Care was taken in the creation of this file. The City cannot accept any responsibility for errors, omissions, or positional accuracy. There are no warranties, expressed or implied. Format: Shapefile or File Geodatabase Feature Class - Data will be provided via City of Portland FTP Site. Online Resource: http://portlandmaps.com/opendata Online Instructions: City of Portland Public/Open Data is distributed via the PortlandMaps Open Data Site - http://portlandmaps.com/opendata. Data not available on the PortlandMaps Open Data site can be requested by contacting the City of Portland CGIS Group - maps@portlandoregon.gov Transfer Size: varies SPCS Zone Identifier: 5076 | |||||
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| Original Data Sources: ------------------------------------- 1) United States Coast & Geodetic Survey, 1888 Columbia River; Sheet No. 6 (Fales Landing to Portland); 1:40000. Available from NOAA Historical Map & Cahart Collection http://anchor.ncd.noaa.gov/states/or.htm) 2) U.S. Army Corps of Engineers, Upper Willamette; Sheet No. 15 (Sellwood to Portland) - 1895; 1:4000. Available from Oregon Historical Society Photographs Department, 1200 SW Park Ave Portland, OR 97205. B&W Photograph of original 1:1000 paper map. 3) U.S. Army Corps of Engineers, Upper Willamette; Sheet No. 14 (Tualitan River to Sellwood) - 1895; 1:4000. Available from Oregon Historical Society Photographs Department, 1200 SW Park Ave Portland, OR 97205. B&W Photograph of original 1:1000 paper map. | ||||||
| 04/02/2020 | Registered TIF image of original 1888 and photographs of 1895 nautical charts using street intersections present in both the historic data (1888, 1895) and the current streets (2001) as well as the Willamette river boundary (in areas where it had not noticably changed.) Manually digitized (on-screen) the 1888 and 1895 river depth sounding points using the registered TIF image as reference. Manually digitized (on-screen) the 1888 and 1895 river contours using the registerted TIF image as a reference. For the 1888 data, depth contours at 6, 11, and 18 feet were digitized directly from the 1888 nautical chart [see source information.] Depths from 20 to 80 feet (in intervals of 10 feet) were visually interpolated using the depth sounding points as reference. For the 1895 data, depth contours were digitized using visual interpolation between depth sounding points at the same river depth. Arcs were smoothed and/or generailized in some cases. THESE CONTOUR LOCATIONS ARE ONE POSSIBLE REPRESENTATION OF THE SUB-SURFACE TOPOGRAPHY. MANY POSSIBLE INTERPRETATIONS EXIST. Using depth points described above as point elevation data and the depth contours as hard breaklines, a Triangulated Irregular Network (TIN) model of river bathymetry was developed in Workstation ArcInfo. The TIN model was interpolated to a grid of 10' by 10' cells in ArcInfo GRID. A low-pass filter was applied to reduce irregularities in the depth grid. The result was used as input for generating depth polygons based on the predefined categorical breakpoints for upper and lower river depths. | |||||
Attribute Tables & Domains
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| Table Description | ||||||
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| Column Sort | Column Name | Column Alias | Column Type | Column Size | Domain Value(s) | Column Description | 1 | EGH_Public_ARCMAP_ADMIN_river_2 | EGH_Public_ARCMAP_ADMIN_river_2 | Numeric | 8 | | | 1 | RANGE_CODE | RANGE_CODE | Numeric | 8 | | | 1 | LOWER_ | LOWER_ | Numeric | 8 | | | 1 | UPPER_ | UPPER_ | Numeric | 8 | | | 1 | DEPTH_CLAS | DEPTH_CLAS | String | 16 | | |