Contour Data and Survey Control for the December 2003 Northridge Bluff Landslide

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Frequently-anticipated questions:

What does this data set describe?

Title:
Contour Data and Survey Control for the December 2003 Northridge Bluff Landslide
Abstract:
Provides contour data of topographic surface and processed survey coordinates for laser scanner locations used to register the lidar data sets.
Supplemental_Information:
Additional information about the field activities from which this data set was derived are available online from the USGS Coastal and Marine Geology InfoBank at <http://walrus.wr.usgs.gov/infobank/l/ld104ca/html/l-d1-04-ca.meta.html>.
  1. How should this data set be cited?

    USGS, 2007, Contour Data and Survey Control for the December 2003 Northridge Bluff Landslide: Open-File Report 2007-1079, U.S. Geological Survey, Coastal and Marine Geology Program, Menlo Park, CA.

    Online Links:

    This is part of the following larger work.

    Collins, Brian D. , Kayen, Robert, Reiss, Thomas, and Sitar, Nicholas, 2007, Terrestrial LIDAR Investigation of the December 2003 and Janauary 2007 Activations of the Northridge Bluff Landslide, Daly City, California: Open-File Report 2007-1079, U.S. Geological Survey, Coastal and Marine Geology Program, Menlo Park, CA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.49646
    East_Bounding_Coordinate: -122.49419
    North_Bounding_Coordinate: 37.68243
    South_Bounding_Coordinate: 37.68063

  3. What does it look like?

    <http://pubs.usgs.gov/of/2007/1079/of2007-1079_data/of2007-1079_images.zip/> (JPEG)
    Un-zipping of2007-1079_images.zip gives access to the image file, of2007-1079_images/Dec2003 Contour Map.jpg. In the PDF document, Figure 7 shows the lidar data coverage and set up locations. Figures 12 and 15 show the area and contour data available.

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

    Beginning_Date: 06-Jan-2004
    Ending_Date: 06-Jan-2004
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: digital data and spreadsheet

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Point data set. It contains the following vector data types (SDTS terminology):

      • Point (222260)

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.00000
      Latitude_of_Projection_Origin: 0.00000
      False_Easting: 0.00000
      False_Northing: 0.00000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.2
      Ordinates (y-coordinates) are specified to the nearest 0.2
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983 (NAD83).
      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.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988 (NAVD88)
      Altitude_Resolution: 0.2
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    Survey Control
    Control points used for registration. (Source: USGS)

    Control Point
    Name of general location of control station site (Source: USGS)

    Character string identifying the station site

    Northing
    UTM Y coordinate of control station location (Source: USGS)

    Range of values
    Minimum:4170670.359
    Maximum:4170671.467
    Units:meters
    Resolution:0.02

    Easting
    UTM X coordinate of control station location (Source: USGS)

    Range of values
    Minimum:544482.783
    Maximum:544502.251
    Units:meters
    Resolution:0.02

    Ground Elev.
    Elevation of control station location (Source: USGS)

    Range of values
    Minimum:48.544
    Maximum:48.544
    Units:meters
    Resolution:0.02

    Instrument Height
    Height of instrument used at control station (Source: USGS)

    Range of values
    Minimum:0.914
    Maximum:0.914
    Units:meters
    Resolution:0.02

    Instrument Elevation
    Elevation of instrument at control station location (Source: USGS)

    Range of values
    Minimum:49.458
    Maximum:49.458
    Units:meters
    Resolution:0.02

    contour lines
    points and vectors describing contour data (Source: USGS)

    X or Easting
    UTM X coordinate of point describing contour data (Source: USGS)

    Range of values
    Minimum:544362.618
    Maximum:544616.350
    Units:meters
    Resolution:0.20

    Y or Northing
    UTM Y coordinate of point describing contour data (Source: USGS)

    Range of values
    Minimum:4170486.700
    Maximum:4170740.442
    Units:meters
    Resolution:0.20

    Z or Ground Elev.
    Elevation Z coordinate of point describing contour data (Source: USGS)

    Range of values
    Minimum:-1.000
    Maximum:139.000
    Units:meters
    Resolution:0.20

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

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

    U.S. Geological Survey
    c/o Brian D. Collins
    USGS, Mail Stop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5466 (voice)
    bcollins@usgs.gov

Why was the data set created?

This data set was developed to present topographic contour data and survey coordinates for engineers, public officials, policy makers, and the general public.

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: 2004 (process 1 of 1)
    The 2003 lidar data was collected from 5 locations of which only one location was collected from a known survey coordinate with a known backsight location. All other locations were georeferenced to the known coordinate through surface registration algorithms. Data was cleaned of bad laser returns, filtered to a minimum point spacing of 20 centimeters, and processed into a continuous triangulated surface. Contours were generated from the processed surface.

    Person who carried out this activity:

    U.S. Geological Survey
    c/o Brian D. Collins
    USGS, Mail Stop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5466 (voice)
    bcollins@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?

    Lidar-derived points and their associated surfaces and contours are accurate to 15 centimeters.

  2. How accurate are the geographic locations?

    Lidar-derived points are accurate to 15 centimeters, measured as three-dimensional error. This includes 1.5 cm laser error, 2 cm survey control error, and 10 cm post-processing registration error.

  3. How accurate are the heights or depths?

    Lidar-derived points are accurate to 15 centimeters, measured as three-dimensional error. This includes 1.5 cm laser error, 2 cm survey control error, and 10 cm post-processing registration error.

  4. Where are the gaps in the data? What is missing?

    Ommissions and gaps in data reflect data out of view or range of the laser scanner at time of data acquisition.

  5. How consistent are the relationships among the observations, including topology?

    Surface and contour data has been visually examined and compared to other data sets of the area to assure logical consistency.

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

Some USGS information accessed through this means may be preliminary in nature and presented without the approval of the Director of the USGS. 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.

This information is not intended for navigational purposes.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey
    c/o Brian D. Collins
    USGS, Mail Stop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5466 (voice)
    bcollins@usgs.gov

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    Although this dataset has been used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. 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. Reference made to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 06-Mar-2007
Metadata author:
U.S. Geological Survey
c/o Brian D. Collins
USGS, Mail Stop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA

(650) 329-5466 (voice)
bcollins@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.8.11 on Tue Mar 27 07:29:41 2007