Global Positioning System (GPS) Control Survey

Frequently-anticipated questions:

• What does this data set describe?
  1. How should 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 should this data set be cited?

   HJW Geospatial, Inc., and Department of Public Works, 1993, Global Positioning System (GPS) Control Survey.

   Online Links:

   • Server=tisent20; Service=5151; User=sfgis; Version=SDE.DEFAULT

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -122.515096

   East_Bounding_Coordinate: -122.166611

   North_Bounding_Coordinate: 37.813519

   South_Bounding_Coordinate: 37.439071

3. What does it look like?

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

   Calendar_Date: 1993

   Currentness_Reference: publication date

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

   Geospatial_Data_Presentation_Form: vector digital data

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):

      • Entity point (65)

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

      The map projection used is Lambert Conformal Conic.

      Projection parameters:

      Standard_Parallel: 37.066667

      Standard_Parallel: 38.433333

      Longitude_of_Central_Meridian: -120.500000

      Latitude_of_Projection_Origin: 36.500000

      False_Easting: 6561666.666667

      False_Northing: 1640416.666667

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000256
      Ordinates (y-coordinates) are specified to the nearest 0.000256
      Planar coordinates are specified in survey feet

      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.
      

      Vertical_Coordinate_System_Definition:

      Altitude_System_Definition:

      Altitude_Resolution: 1.000000

      Altitude_Encoding_Method:

      Explicit elevation coordinate included with horizontal coordinates

7. How does the data set describe geographic features?

   SDE.SFGIS.PHYS_SURVEYPTS

   OBJECTID

   Unique ID (Source: ESRI ArcGIS)

   Sequential unique whole numbers that are automatically generated.

   STATION

   Coordinates defining the features.

   NORTHING

   Coordinates defining the features.

   EASTING

   Coordinates defining the features.

   COMBFACT

   ELEV

   SFXYZ_ID

   SHAPE

   Feature geometry. (Source: ESRI)

   Coordinates defining the features.

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • HJW Geospatial, Inc.
   • Department of Public Works

2. Who also contributed to the data set?

   Dept. of Public Works

3. To whom should users address questions about the data?
   City and County of San Francisco Department of Telecommunications
   875 Stevenson St. 5th Floor
   San Francisco, CA 94103
   USA
   

   415-554-0800 (voice)
   415-554-0886 (FAX)
   Jeff.Johnson@sfgov.org
   

   Hours_of_Service: 8:00 AM - 5:00 PM

Why was the data set created?

Global Positioning System (GPS) Control Survey: a GPS survey of 65 survey control points was conducted, generating coordinate and elevation data for the survey point network used for Basemap development. The network meets the National Geodetic Survey standard for Second Order, Class 2.

How was the data set created?

1. From what previous works were the data drawn?

   (source 1 of 1)

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?

   none

2. How accurate are the geographic locations?

   none

3. How accurate are the heights or depths?

   none

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

   none

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

   none

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: none

1. Who distributes the data set? (Distributor 1 of 1)
   City and County of San Francisco Dept. of Telecommunications
   c/o Jeff Johnson
   Senior Application Developer
   875 Stevenson St. 5th Floor
   San Francisco, CA 95103
   USA
   

   415-554-5909 (voice)
   415-554-0886 (FAX)
   jeff.johnson@sfgov.org
   

   Hours_of_Service: 8:00 AM - 5:00 PM

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

   City and County of San Francisco, Dept. of Telecommunications and Information Services

3. What legal disclaimers am I supposed to read?

   The City and County of San Francisco does not guarantee the accuracy, adequacy, completeness or usefulness of any information. The City does not warrent the positional or themetic accurancy of the GIS data. The GIS data and cartographic digital files are not legal representations of the depicted data. Information shown on these maps is derived from public records that are constantly undergoing change. Under no circumstances shall GIS mapping be used for final design purposes. The City provides this information on an "as is" basis without warranty of any kind, express or implied. including but not limited to warranties of merchantability or fitness for a particular purpose, and assumes no responsibility for anyone's use of the information.

4. How can I download or order the data?

Who wrote the metadata?

Dates:

Last modified: 11-Jul-2005

Metadata author:

City and County of San Francisco Dept of Telecommunications
875 Stevenson St. 5th Floor
San Francisco, CA 94103
USA

415-554-0800 (voice)
415-554-0886 (FAX)
gis@sfgov.org

Hours_of_Service: 8:00 AM - 5:00 PM

Metadata standard:

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

Metadata extensions used:

• <http://www.esri.com/metadata/esriprof80.html>
• <http://www.esri.com/metadata/esriprof80.html>