Cape Cod Bay: Polygon boundaries for source data of a continuous bathymetry and topography terrain model of the Massachusetts coastal zone and continental shelf: (Esri polygon shapefile, Geographic, NAD 83).

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   U.S. Geological Survey, 2018, Cape Cod Bay: Polygon boundaries for source data of a continuous bathymetry and topography terrain model of the Massachusetts coastal zone and continental shelf: (Esri polygon shapefile, Geographic, NAD 83).: data release DOI:10.5066/F72806T7, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

   Online Links:

   • https://doi.org/10.5066/F72806T7
   • https://www.sciencebase.gov/catalog/item/5a464a15e4b0d05ee8c0548d

   This is part of the following larger work.
   Andrews, Brian D., Baldwin, Wayne E., Sampson, Daniel W., and Schwab, William C., 2018, Continuous bathymetry and elevation models of the Massachusetts coastal zone and continental shelf: data release DOI:10.5066/F72806T7, U.S. Geological Survey, Reston, Virginia.

   Online Links:

   • https://doi.org/10.5066/F72806T7
   • https://www.sciencebase.gov/catalog/item/5a451a3ce4b0d05ee8bedfdc

   Other_Citation_Details:

   Suggested citation: Andrews, B.D., Baldwin, W.E., Sampson, D.W., and Schwab, W.C., 2018, Continuous bathymetry and elevation models of the Massachusetts coastal zone and continental shelf: U.S. Geological Survey data release, https://doi.org/10.5066/F72806T7.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.838962
   East_Bounding_Coordinate: -69.756605
   North_Bounding_Coordinate: 42.134424
   South_Bounding_Coordinate: 41.680251
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/5a464a15e4b0d05ee8c0548d?name=CapeCodBay_Source.jpg (JPEG)

   Image of source data boundaries for the terrain model of Cape Cod Bay and surrounding elevations of the Massachusetts Coastal Zone. File is located in the compressed zip file.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 1933

   Ending_Date: 2016

   Currentness_Reference:

   ground condition

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: Vector Digital Data Set (Polygon)
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • GT-polygon composed of chains (34)
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_North_American_1983.
      The ellipsoid used is GRS 1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      
7. How does the data set describe geographic features?

   CapeCodBay_Source

   Table containing attribute information associated with the data set. (Source: USGS)

   FID

   Internal feature number. (Source: Esri)

   Range of values
   Minimum:	0
   Maximum:	33

   Shape

   Feature geometry. (Source: Esri) Coordinates defining the features.

   Source

   Simplified name of the survey used as input data using either the agency acronym, and date, or in just the survey ID (NOAA). (Source: USGS) character set

   SurvYear

   The year the survey was conducted, in some cases, the source grid included data collected during several years. In these cases, the SurvYear is the first year of the multiple surveys which are documented in the metadata for the"CapeCodBay_10m.tif" (Source: USGS)

   Range of values
   Minimum:	1933
   Maximum:	2016
   Units:	Year

   PubLink

   URL to published data files and metadata for each survey. For LiDAR datasets, this is the url where the laz files were downloaded. (Source: USGS) character set

   SourceType

   Sensor or method used to collect the data (Source: Producer defined)

   Value	Definition
   Lead Line	Hand-deployed sounding device that is usally positioned with visual bearings to know objects ashore. These data, collected in the 1930', are the oldest sounding and of lowest quality.
   Fathometer	refers to a digital sounding device recorded on paper used in the 1940's. Navigation for these surveys used three-point triangulation from visual observations to objects ashore.
   LiDAR	LIght Detection and Range
   Multibeam	Multibeam Sonar
   Swath	Interferometric Sonar

   Shape_Leng

   Length of the polygon feature in meters calculated in the feature class using UTM Zone 19 meters NAD 83, before it was exported as shapefile. (Source: Esri)

   Range of values
   Minimum:	4415.975
   Maximum:	1793836.69113
   Units:	meters

   Shape_Area

   Area of feature in meters squared calculated in the feature class using UTM Zone 19 meters NAD 83, before exporting to shapefile. (Source: Esri)

   Range of values
   Minimum:	205481.5477
   Maximum:	566277137.820454
   Units:	meters squared

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • U.S. Geological Survey
2. Who also contributed to the data set?

   Please recognize the U.S. Geological Survey (USGS) as the source of this information.

3. To whom should users address questions about the data?
   Brian Andrews

   U.S. Geological Survey

   Geographer

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2348 (voice)

   508-457-2310 (FAX)

   bandrews@usgs.gov

Why was the data set created?

The purpose of this polygon feature class is to identify the spatial extent and provenance of the source data used to create the continuous elevation surface. In addition the shapefile will also provide an inventory of the most recent elevation and bathymetry datasets within the Massachusetts coastal zone and offshore water and identify areas of the offshore waters that are only covered by historical lead-line soundings and should be updated by using new survey methods.

How was the data set created?

1. From what previous works were the data drawn?
2. How were the data generated, processed, and modified?

   Date: Jun-2016 (process 1 of 7)

   PROCESS STEP 1: CREATE EMPTY POLYGON FEATURE CLASS TO STORE THE OUTLINES OF ALL THE SOURCE DATA.
   Create an empty polygon feature class within a file geodatabase using the context menu in ArcCatalog (v. 10.3.1). Projection is set to UTM Zone 19 NAD 83. Add the following fields to the new feature class using the "add field" menu in the attribute table view: Source, SurvYear, PubLink, SourceType. All processing steps were completed by Brian Andrews. Person who carried out this activity:
   

   Brian Andrews

   U.S. Geological Survey

   Geographer

   384 Woods Hole Rd

   Woods Hole, MA
   

   USA

   508-548-8700 x2348 (voice)

   508-457-2310 (FAX)

   bandrews@usgs.gov

   Data sources produced in this process:

   • CapeCodBay_Source (feature class)

   Date: Jul-2016 (process 2 of 7)

   PROCESS STEP 2: CREATE POLYGON BOUNDARY FILES FOR ALL LiDAR DATA.
   An 8-bit integer raster was created for each source LiDAR GeoTIFF listed in "Step 2" of the CapeCodBay_10m.tif metadata using the grid query "Value less than 1000." The resulting integer raster was converted to polygon using the Raster to Polygon tool in ArcGIS (v. 10.3.1). Data sources produced in this process:

   • "SurveyName"_Mask

   Date: Jul-2016 (process 3 of 7)

   PROCESS STEP 3: CREATE BOUNDARY FILES FOR SWATH AND MULITBEAM DATA.
   An 8-bit integer raster was created for each source swath bathymetry grid listed in "Step 3 and 4" of the CapeCodBay_10m.tif metadata using the grid query "Value less than 0." The resulting integer raster was converted to polygon using the Raster to Polygon tool in ArcGIS (v. 10.3.1) Data sources produced in this process:

   • "SurveyName"_Mask

   Date: Jul-2016 (process 4 of 7)

   PROCESS STEP 4: CREATE BOUNDARY FILES FOR ALL HISTORICAL NOS SOUNDING DATA.
   Create an empty polygon feature class for each of the historical NOS surveys using the context menu in ArcCatalog (v. 10.3.1). Projection is set to UTM Zone 19, NAD 83 (2011). Edit each of the polygons and digitize a boundary that encompasses all the input soundings. Data sources produced in this process:

   • "SurveyName"_Mask

   Date: Jul-2016 (process 5 of 7)

   PROCESS STEP 5: CLIP AND MERGE THE SOURCE POLYGONS INTO ONE FEATURE CLASS.
   This process was completed in three basic steps based on a data hierarchy using both qualitative and quantitative comparison between datasets in any areas of overlap. Starting with the LiDAR data, the individual polygons for each of the LiDAR surveys were compared for areas of overlap. In areas of overlap the newest LiDAR data with highest quality was generally used to clip (remove) overlapping older data used to create the terrain model. Qualitative criteria for determining which data to keep in areas of overlap included data density, data collection date, and data quality (are survey line artefacts visible). For example, along the south shore of Cape Cod, overlap exists between the 2007 and 2010 Army Corps of Engineers surveys. The full extent of the 2010 survey was used to clip (remove), the areas from the 2007 polygon because the 2010 data were more recent. The resulting clipped polygons were used later to extract the desired data for export as multipoint feature classes into the feature dataset used to create the terrain model. The vertical difference between overlapping raster data (LiDAR, swath, or multibeam) was used as a quantitative criteria for determining which data to retain in areas of overlap. Once these comparisons were conducted the polygons were clipped, then appended to the "MassBay_Source" feature class created in Step 1 above.
   Second, the polygons for swath and multibeam created in Step 3 above were clipped and appended to the "CapeCodBay_Source" feature class in a similar manner as the LiDAR polygons. Polygon masks of newer multibeam data were used to clip older survey data in the areas of overlap. The final polygons representing swath and multibeam data were used later to extract the desired depth data for export as a multipoint feature class to create the terrain model. Each source survey was exported as a separate multipoint, or simple point, feature class to facilitate data management.
   Finally, the polygons for each of the historical NOS surveys from Step 4 above were compared in areas of overlap with newer multibeam or LiDAR data and clipped to remove older historical sounding data. During the clip process, an additional buffer of 50 to 100 meters was applied using the "Buffer Distance" in the ArcGIS Clip Tool under the Edit Menu. This 50-100 meter gap created a smoother transition during the gridding process between high resolution data (LiDAR and multibeam) and low resolution data (historical NOS soundings). These edited polygons were then used to extract the desired sounding data for export as point feature class into the Terrain Model feature data set. The final polygons for each survey were appended to the "CapeCodBay_Source" feature class. Data sources used in this process:

   • "SurveyName"_Mask

   Data sources produced in this process:

   • CapeCodBay_Source

   Date: Jul-2016 (process 6 of 7)

   PROCESS STEP 6: EXPORT FEATURE CLASS TO SHAPEFILE:
   Finally, exported the CapeCodBay_Source feature class into a Esri Shapefile using the context menu in ArcCatalog (v. 10.3.1). The projection of the output shapefile was set to Geographic NAD 83 during the export process. Data sources used in this process:

   • CapeCodBay_Source feature class

   Data sources produced in this process:

   • CapeCodBay_Source.shp

   Date: 07-Aug-2020 (process 7 of 7)

   Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?
   No formal attribute accuracy tests were conducted.
2. How accurate are the geographic locations?
   This polygon shapefile was generated by a combination of digitizing around actual sounding data, and converting rasters to polygons. Each feature in the shapefile encompasses the extent of each input dataset. The horizontal accuracy is dependant on the accuracy of the input dataset, and the scale used to digitize/edit the polygon features.
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   The individual polygons only delineate the extent of data used to compile the terrain model and may not include all the data collected during the individual survey. Gaps exist between adjacent polygons.
5. How consistent are the relationships among the observations, including topology?
   Polygon boundaries were created to outline the spatial extents of each input data source for the terrain model. The boundaries for the LiDAR and multibeam data were created by converting the boundary of the raster data to a polygon. The boundaries for the historical NOS sounding data were created by digitizing a boundary polygon around the extent for each of the datasets such that adjacent polygons do not overlap. The perimeter boundary of all four polygon datasets published in this data release were designed to overlap in order to create a seamless surface if the resulting GeoTIFFs are mosaicked together. General guidelines were established for the selection of the source elevation data, but for such a large area and complicated series of possible input datasets, the same source dataset may not have been chosen – therefore areas of overlap of the four individual datasets (BuzzBay_Source, CapeCodBay_Source , MassBay_Source, and Ntk_VS_Source) may not indicate the same source dataset.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None.
Use_Constraints:

Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations.

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey-ScienceBase

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   USA

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? CapeCodBay_Source.zip: file contains the polygon feature class (CapeCodBay_Source.shp), CapeCodBay_Source.jpg browse graphic, and the associated FGDC CSDGM metadata in XML, HTML, FAQ, and text formats.
3. What legal disclaimers am I supposed to read?

   Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	This WinZip file contains a polygon shapefile, and associated metadata for source data used to produce the terrain model of Cape Cod Bay. in format shapefile (version ArcGIS (v. 10.3.1)) Esri polygon shapefile Size: 5.6
     Network links:	https://www.sciencebase.gov/catalog/file/get/5a464a15e4b0d05ee8c0548d?name=CapeCodBay_Source.zip https://www.sciencebase.gov/catalog/item/5a464a15e4b0d05ee8c0548d

   • Cost to order the data: None

5. What hardware or software do I need in order to use the data set?

   To utilize this data, the user must have software capable of reading an Esri shapefile.

Who wrote the metadata?

Dates:

Last modified: 07-Aug-2020

Metadata author:

Brian Andrews

U.S. Geological Survey, Northeast Region

Geographer

384 Woods Hole Road

Woods Hole, MA

508-548-8700 ext. 2348 (voice)

bandrews@usgs.gov

Metadata standard:

FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)