Urban Areas of the United States

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?

   U.S. Geological Survey, 200101, Urban Areas of the United States: U.S. Geological Survey, Reston, Virginia.

   Online Links:

   • <http://nationalatlas.gov/atlasftp.html>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: 172

   East_Bounding_Coordinate: -66

   North_Bounding_Coordinate: 72

   South_Bounding_Coordinate: 18

3. What does it look like?

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

   Calendar_Date: Jan-2001

   Currentness_Reference: publication date

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

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 (6176)

   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 0.02083333. Longitudes are given to the nearest 0.02083333. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222.
      

7. How does the data set describe geographic features?

   Urban Areas (described by Urbanap020.dbf)

   Urban areas are places where large populations exist. (Source: U.S. Geological Survey)

   Shape

   The representation of the entity in the data. (Source: U.S. Geological Survey)

   Value	Definition
   Polygon	A 2-dimensional element.

   Area

   The size of the shape in coverage units. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	0.000
   Maximum:	0.298

   Perimeter

   The perimeter of the shape in coverage units. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	0.001
   Maximum:	6.774

   Urbanap020

   Internal feature number. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	2
   Maximum:	6177

   Name

   The name of the urban area. (Source: U.S. Geological Survey)

   There is no predefined set of valid urban area names. Name represents the most significant place that is in the polygon.

   State

   The 2-character FIPS code of the State or State equivalent. Where the urban area falls in more than one State, the codes are separated by dashes: DC-VA-MD. (Source: U.S. Geological Survey)

   Formal codeset
   Codeset Name:	Codes for the Identification of the States, the District of Columbia and the Outlying Areas of the United States, and Associated Areas, FIPS 5-2.
   Codeset Source:	U.S. Department of Commerce, National Institute of Standards and Technology

   State_fips

   The 2-digit FIPS code of the State or State equivalent. Where the urban area falls in more than one State, the codes are separated by dashes: 11-51-24. (Source: U.S. Geological Survey)

   Formal codeset
   Codeset Name:	Codes for the Identification of the States, the District of Columbia and the Outlying Areas of the United States, and Associated Areas, FIPS 5-2.
   Codeset Source:	U.S. Department of Commerce, National Institute of Standards and Technology

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?

3. To whom should users address questions about the data?
   Gita Urban-Mathieux
   U.S. Geological Survey
   521 National Center
   Reston, VA 20192
   

   703-648-5175 (voice)
   [email protected]
   

Why was the data set created?

These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:2,000,000-scale data. No responsibility is assumed by the U.S. Geological Survey in the use of these data.

How was the data set created?

1. From what previous works were the data drawn?

   DCW (source 1 of 5)

   National Imagery and Mapping Agency (NIMA), 1994, Digital Chart of the World: U.S. Geological Survey, Reston, VA.

   Type_of_Source_Media: CD-ROM

   Source_Contribution: spatial and attribute information

   ATLAS-STATE (source 2 of 5)

   U.S. Geological Survey, 1998, State Boundaries of the United States: U.S. Geological Survey, Reston, Virginia.

   Type_of_Source_Media: online

   Source_Scale_Denominator: 2000000

   Source_Contribution: spatial information

   ATLAS-CITIES98 (source 3 of 5)

   U.S. Geological Survey, 1998, Cities and Towns of the United States: U.S. Geological Survey, Reston, Virginia.

   Type_of_Source_Media: online

   Source_Scale_Denominator: 2000000

   Source_Contribution: spatial and attribute information

   ATLAS-HY (source 4 of 5)

   U.S. Geological Survey, 1998, Hydrography Features of the United States: U.S. Geological Survey, Reston, Virginia.

   Type_of_Source_Media: online

   Source_Scale_Denominator: 2000000

   Source_Contribution: spatial information

   ATLAS-URBAN98 (source 5 of 5)

   U.S. Geological Survey, 1998, Urban Areas of the United States: U.S. Geological Survey, Reston, Virginia.

   Type_of_Source_Media: online

   Source_Scale_Denominator: 2000000

   Source_Contribution: spatial information

2. How were the data generated, processed, and modified?

   Date: 1998 (process 1 of 2)

   Urban polygons from the Digital Chart of the World (DCW) CD-ROM were extracted and converted to Arc/INFO format. Where the urban boundaries extended beyond the shoreline of ATLAS-STATES, the shoreline was matched to the ATLAS-STATES shoreline. Names of the urban areas were added using names in ATLAS-CITIES98. In large metropolitan areas many smaller areas were labeled as part of the metropolitan area. The State in which the urban area is located was also added. Several areas were modified to conform to the 1:2,000,000-scale hydrography (ATLAS-HY) layer. Some smaller polygons that represent undeveloped areas within the urban area were removed and merged with the larger urban area. Military reservations were also removed. Finally, the attribute for State FIPS was added.

   Data sources used in this process:

   • DCW
   • ATLAS-STATE
   • ATLAS-HY
   • ATLAS-CITIES98

   Data sources produced in this process:

   • ATLAS-URBAN98

   Date: Jan-2001 (process 2 of 2)

   The spellings for San Francisco, CA and Bismarck, ND were corrected.

   Data sources used in this process:

   • ATLAS-URBAN98

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?

   This data set contains urban areas for the 50 United States.

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

   No additional checks for topological consistency were performed on this data set.

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. Acknowledgment of the National Atlas of the United States of America and (or) the U.S. Geological Survey would be appreciated in products derived from these data.

1. Who distributes the data set? (Distributor 1 of 1)
   Earth Science Information Center, U.S. Geological Survey
   507 National Center
   Reston, VA 20192
   

   1-888-ASK-USGS (1-888-275-8747) (voice)
   

   Contact_Instructions:

   In addition to the address above, there are other ESIC offices throughout the country. A full list of these offices is at <http://mapping.usgs.gov/esic/esic_index.html>.

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

3. What legal disclaimers am I supposed to read?

   Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. No responsibility is assumed by the U.S. Geological Survey in the use of these data.

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

     Data format:	ESRI Shapefile
     Network links:	<http://nationalatlas.gov/atlasftp.html>

     Data format:	SDTS
     Network links:	<http://nationalatlas.gov/atlasftp.html>

   • Cost to order the data:

     There is no charge for the online option. For National Atlas files ordered on CD-ROM there is a base price of $45.00 per disc, a handling fee of $5.00, and a per-file charge based on file size. The charge for files less than 10 megabytes in size is $1.00. The charge for files that range in size from 10 to 150 megabytes is $7.50. The charge for files of 150 megabytes or larger is $15.00. The charge is $1.00 for the Urban Areas of the United States data set.

   • Special instructions:

     To order files on CD-ROM, please see <http://nationalatlas.gov/atlasftp.html#q12>.

Who wrote the metadata?

Dates:

Last modified: 29-Oct-2001

Metadata author:

Gita Urban-Mathieux
U.S. Geological Survey
521 National Center
Reston, VA 20192

703-648-5175 (voice)
[email protected]

Metadata standard:

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