U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), Santa Cruz, CA., 2012, Hydro-flattened Elevation Area Outlines for DEMs of the North-Central California Coast (Hydro_flattened_water.shp):.This is part of the following larger work.
U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), Santa Cruz, CA., 2012, A Seamless, High-Resolution Digital Elevation Model (DEM) of the North-Central California Coast: U.S. Geological Survey Data Series Data Series 684.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 0.000001
Ordinates (y-coordinates) are specified to the nearest 0.000001
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
Polygon attributes none
California State University, Monterey Bay (CSUMB) and Fugro Pelagos, Inc., for California State Waters Mapping Project (CSWMP) from Pat Iampietro;
Pillar Point Harbor from Anne Sturm (U.S. Army Corps of Engineers);
National Geophysical Data Center (NGDC);
National Oceanic and Atmospheric Administration (NOAA);
Marin County from Brian Quinn (County of Marin GIS Division of Community Development Agency);
Bolinas Lagoon from Matt Brennan (ESA-PWA);
Carignan, K.S., Taylor, L.A., Eakins, B.W., Caldwell, R.J., Friday, D.Z., Grothe, P.R., and Lim, E., 2011, Digital elevation models of central California and San Francisco Bay: Procedures, data sources and analysis: NOAA Technical Memorandum NESDIS NGDC-52, 49 p. and datasets, available at <http://www.ngdc.noaa.gov/dem/squareCellGrid/download/741>
(831) 460-7556 (voice)
(831) 427-4748 (FAX)
pbarnard@usgs.gov
To denote small lakes or ponds within the DEM where elevations are hydro-flattened. Elevations within these small areas reflect water surface elevations, not bathymetric elevations.
California State University, Monterey Bay, Unknown, Multibeam bathymetry.Online Links:
U.S. Geological Survey, lidar acquired by Terrapoint, Unknown, ARRA-CA_SanFranCoast_2010 lidar.Online Links:
San Francisco State University, lidar acquired by Earth Eye, Unknown, Golden Gate Lidar Project.
California State Ocean Protection Council, Unknown, 2010 Coastal CA Lidar, Delivery Area 3.
NOAA National Geophysical Data Center, 2011, Digital elevation models of central California and San Francisco Bay: Procedures, data sources and analysis. NOAA Technical Memorandum NESDIS NGDC-52.Online Links:
U.S. Army Corps of Engineers, Unknown, Pillar Point Harbor survey.
U.S. Geological Survey, 2008, Interferometric Sidescan Bathymetry, Sediment and Foraminiferal Analyses; a New Look at Tomales Bay, California.
GIS Division of Community Development Agency County of Marin, unknown, Marin County Terrain Dataset.
Environmental Science Associates, Philip Williams and Associates, Unknown, Bolinas Lagoon Bathymetry.
U.S. Geologial Survey, Unknown, O-12-09-CA.Online Links:
U.S. Geologial Survey, 1991, Pollution Studies of Drakes Estero, and Abbotts Lagoon Point Reyes National Seashore, California, USA.Online Links:
(Detailed DEM Construction Procedures) Performed by Amy Foxgrover and Patrick Barnard: 1. Divide study area into ~10 km alongshore segments A. Define DEM coverage area/polygon that extends ~10 km alongshore, from 3 nautical miles offshore inland beyond the +20 m topographic contour B. Ensure that adjacent DEM coverage areas overlap by ~250 m 2. Acquire most recent or highest resolution data sets in DEM coverage areas A. Lidar B. Multibeam bathymetry C. Local high-resolution beach topography (usually ATV-acquired) and nearshore bathymetry (usually PWC-acquired). 3. Fill gaps with older/lower resolution data sets A. Lower resolution DEMs - for example, NGDC's 10-m resolution tsunami inundation DEM, (Carignan and others, 2010) in Bodega Harbor B. Bathymetric data derived from single beam bathymetry - for example, 1980s survey in Drakes Estero and 1998 bathymetry in Bolinas Lagoon 4. Convert all data sets into identical horizontal coordinate system, vertical datum, and grid resolution A. Horizontal coordinate system: UTM NAD83 Zone 10 North B. Vertical Datum: NAVD88 I. If different [usually Mean Lower Low Water (MLLW)], convert using local NOAA tide station information [<http://tidesandcurrents.noaa.gov/> (last accessed December 12, 2011)] based on survey metadata C. Grid resolution: 2 m I. If already gridded at higher (<2 m) resolution, resample to 2 m using bilinear interpolation II. If already gridded at a lower resolution (> 2m), export as xyz file, reimport as xyz points, create TIN (triangular irregular network), create 2-m grid from TIN using linear interpolation of the TIN triangles, and clip to survey extent III. Ungridded: a) Lower resolution surveys (for example, PWC-collected bathymetry): create TIN from points then convert to 2-m grid using linear interpolation of the TIN triangles 5. Clip datasets to DEM/coverage needs, if necessary A. Useful for data management and processing efficiency B. Necessary for very large datasets, such as county-wide lidar data sets (for example, Golden Gate Lidar Project data) C. Remove ocean water surfaces and offshore rocky outcrops/islands I. Aerial topographic lidar from 2010 was provided as bare-earth hydro-flattened DEMs. The breakline polygons provided with aerial lidar data were used to generate 2-m resolution grids of water surfaces over the ocean or tidal embayments where bathymetric data was to be inserted. Use this grid to mask out water surfaces in the topographic DEM using the Set Null tool in Arc Toolbox. II. Hydro-flattened surfaces of small inland water bodies were retained in the final DEM. Since these areas are of less importance for this research, no attempt was made to obtain bathymetric depths for these inland ponds or lakes (for example, Lake Merced in San Francisco). Hydro-flattened features that were retained in the final DEM are provided in shapefile format. III. Extract small islands and rocky outcrops from topographic lidar datasets using breaklines provided. These features are not included in the nearshore interpolation, but are incorporated into the final DEM in step 8. 6. Manage overlapping data sets A. Data sets were allowed to overlap extensively only if they are from the same time period, of comparable quality, and not within the dynamic nearshore region, otherwise allow only minimal (~10-30 m) overlap to ensure smooth DEM transitions B. Clip low-resolution data sets pushed to 2-m resolution, such as Personal Watercraft data and regional DEMs, to minimal overlap with adjacent high-resolution data sets (usually multibeam and topographic lidar) C. Clip topographic lidar so that only a single dataset is used for the coastal zone. Where it exists, the USGS lidar is given highest preference in the nearshore zone because it was collected in the summer and fall of 2010, when the beach morphology was less likely to influenced by winter storm events. The Golden Gate Lidar Project data are used for all reaches landward of the USGS lidar coverage (roughly 10 m elevation and higher) and along the coastline where USGS lidar was not collected. The OPC lidar is present only in two small sections that are not covered by USGS or GGLP lidar (within DEM sections 1 and 14). 7. Fill in data gaps between high-resolution data sets A. If no high-resolution data are available between the offshore multibeam bathymetry and coastal topographic lidar in protected harbors/embayments, or in other areas where interpolation from surrounding data sets will create a surface unlikely to reflect actual bathymetry/topography accurately, fill in gaps with regional DEMs or other low-resolution data sets. Otherwise, interpolate across gaps. I. Filling in harbors or embayments using regional DEMs/other low-resolution data: a) Clip best available regional DEM or bathymetry to gap area, allowing only minimal overlap (~20 m) with adjacent high-resolution data sets b) Export clipped grid as xyz file, reimport as points, create TIN, create 2-m grid from TIN, clip to gap extent II. Interpolation across nearshore gaps: a) Create preliminary DEM using Mosaic tool with the following settings: Coordinate System: UTM Zone 10 North Pixel Type: 32 Bit Float Cell Size: 2 Mosaic Method: Blend Mosaic Color Map: Last b) Create polygon of data gap(s) to fill within the preliminary DEM surface c) Buffer the data gap polygon with a linear distance of 20 m using the Buffer tool in Arc Toolbox d) Clip preliminary DEM using the buffered polygon, export clipped grid as xyz, reimport as points (fig. 3B), create TIN, create 2-m grid from TIN, clip to buffered gap extent III. Interpolation around perimeter of Bolinas Lagoon and Drakes Estero: a) Fill any narrow gaps between bathymetry grids of Bolinas Lagoon and Drakes Estero and the nearest high-resolution topography using the same procedure as used above for interpolating across nearshore gaps. 8. Compile final DEMs A. Load all datasets for DEM B. Verify all significant data gaps filled (few missing cells allowed) in DEM coverage area C. Build interim DEM using Mosaic to New Raster tool in ArcGIS with same setting as noted above in Step 7 D. Build final DEM using Mosaic to New Raster tool in ArcGIS. Input rasters are the above interim DEM and a grid of small islands or rocky outcrops obtained from lidar. The islands are given top priority in the mosaicking algorithm so that island elevations from the lidar overwrite elevations from the nearshore interpolation. E. Clip output to DEM coverage area F. Create contours and plot cross-shore profiles to verify data quality and consistency
Refer to the DEM Accuracy and Limitations section in this Data Series for an explanation of the accuracy of the identification of the entities and assignments of values in the dataset and a description of the tests used.
Refer to the DEM Accuracy and Limitations section in this Data Series for an explanation of the accuracy of the horizontal coordinate measurements and a description of the tests used.
Refer to the DEM Accuracy and Limitations section in this Data Series for an explanation of the accuracy of the vertical coordinate measurements and a description of the tests used.
Refer to the DEM Construction Methods section in this Data Series for information about omissions, selection criteria, generalization, definitions used, and other rules used to derive the dataset.
Refer to the DEM Construction Methods section in this Data Series for an explanation of the fidelity of relationships in the data set and tests used.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Not suitable for navigation.
Read and fully comprehend the metadata prior to data use.
Acknowledge the U.S. Geological Survey (USGS), the originator, when using the dataset as a source. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the responsibility of the user.
Majority of data (that is, lidar, multibeam bathymetry) derived from topographic/bathymetry data collected at 1-2 m horizontal resolution,with vertical uncertainty at time of data collection ranging from 10 cm to 1 m. Use at greater scales not advised. See full Data Series report for more information:
Foxgrover, A.C., and Barnard, P.L., 2012, A seamless, high-resolution digital elevation model (DEM) of the north-central California coast: U.S. Geological Survey Data Series 684, 11 p. and datasets, available at <https://pubs.usgs.gov/ds/684>
(831) 460-7556 (voice)
(831) 427-4748 (FAX)
pbarnard@usgs.gov
U.S. Geological Survey Data Series 684
Please recognize the U.S. Geological Survey (USGS) as the source of this information.
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.
The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.
Data format: | Compressed file including Arcinfo grid and metadata. (version 10.0) Arcinfo grid Size: 0.526 |
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Network links: |
<https://pubs.usgs.gov/ds/684/> |
(831) 460-7556 (voice)
(831) 427-4748 (FAX)
afoxgrover@usgs.gov