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Digital representation of "Atlas of United States Trees" by Elbert L. Little, Jr.

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, 1999, Digital representation of "Atlas of United States Trees" by Elbert L. Little, Jr.: U.S. Geological Survey Professional Paper 1650.

   Online Links:

   • <http://climchange.cr.usgs.gov/info/veg-clim/>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -180.0

   East_Bounding_Coordinate: -50.0

   North_Bounding_Coordinate: 83.0

   South_Bounding_Coordinate: 7.0

3. What does it look like?

   <http://climchange.cr.usgs.gov/data/atlas/little/> (PDF)

   individual browse graphics are available for each map.

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

   Calendar_Date: 1999

   Currentness_Reference: Publication date

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

   Geospatial_Data_Presentation_Form: map

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

   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 0.01. Longitudes are given to the nearest 0.01. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.98.
      

7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview:

   The only user defined attribute is "code". Polygons attributed with a 1 denotes presence of the tree species in that area. A code attribute of O indicates that the species is absent.

   Entity_and_Attribute_Detail_Citation: none

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?
   Robert S. Thompson
   U.S. Geological Survey
   Geologist
   Denver Federal Center
   MS 980, Box 25046
   Denver, Colorado 80225-0046
   USA
   

   303-236-5347 (voice)
   303-236-5349 (FAX)
   rthompson@usgs.gov
   

Why was the data set created?

To create a digital representation of the vegetation range maps published in "Atlas of United States Trees" by Elbert L. Little, Jr.

How was the data set created?

1. From what previous works were the data drawn?

   Little, 1971 (source 1 of 3)

   Little, Elbert L., Jr., 1971, Atlas of United States Trees, Volume 1: Conifers and Important Hardwoods.

   Type_of_Source_Media: paper

   Source_Contribution: Distribution and extents of tree species.

   Little, 1976 (source 2 of 3)

   Little, Elbert L., Jr., 1976, Atlas of United States Trees, Volume 3: Minor Western Hardwoods.

   Type_of_Source_Media: paper

   Source_Contribution: Distribution and extents of tree species.

   Little, 1977 (source 3 of 3)

   Little, Elbert L., Jr., 1977, Atlas of United States Trees, Volume 4: Minor Eastern Hardwoods.

   Type_of_Source_Media: paper

   Source_Contribution: Distribution and extents of tree species.

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

   Date: 1999 (process 1 of 3)

   The coverage was created by scanning the map of each species range from the book, registering to a county coverage at 1:2,000,000 scale using the ARC/INFO REGISTER command, and rectifying.

   Date: 1999 (process 2 of 3)

   Digitized ploygon boundaries on screen using scanned and registered images as reference.

   Date: 1999 (process 3 of 3)

   Added CODE attributes to coverages; assigned attribute of 1 to polygons representing presence of plant species and 0 to all other polygons.

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?

   The single user-defined attribute ("code") has an enumerated domain (values of 0 or 1 only), so numerical measures of accuracy are not applicable. The data sets were checked for attribute accuracy by visually comparing color-coded plots of each dataset with the source maps.

2. How accurate are the geographic locations?

   At least 90% of the points tested on hard copy printout are within 1/50 inch (0.5mm) of the source data.

3. How accurate are the heights or depths?

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

   All polygons on the printed source maps are represented in the digital coverages.

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

   In some instances, data for the United States portions of the maps were derived from source maps at 1:10,000,000 scale and the portions outside the United States were derived from sources at approximately 1:27,000, 000 scale. The coverages were checked for node, intersection, and duplication errors and corrected when necessary. All polygons were snapped closed at nodes.

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)
   U.S. Geological Survey
   c/o Randall Schumann
   Denver Federal Center
   MS 980, Box 25046
   Denver, CO 80225-0046
   USA
   

   (303) 236-1525 (voice)
   (303) 236-5349 (FAX)
   rschumann@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 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.

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

     Data format:	ArcView Shapefile
     Network links:	<http://climchange.cr.usgs.gov/data/atlas/little/>

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 28-Sep-1999
Last Reviewed: 27-Sep-1999

Metadata author:

U.S. Geological Survey
c/o Sharon Smith
GIS Computer Specialist
Denver Federal Center
MS 980, Box 25046
Denver, Colorado 80225-0046
USA

303-236-4610 (voice)
303-236-5349 (FAX)
ssmith@usgs.gov

Metadata standard:

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