Accuracy Assessment FAQ Metadata

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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?
  8. What biological taxa does this data set concern?
• 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?

   Virginia Department of Conservation and Recreation, Division of Natural Heritage, 200510, Locations of thematic accuracy assessment sampling points in Colonial National Historical Park.

   Online Links:

   • <http://biology.usgs.gov/npsveg/ftp/vegmapping/colo/coloaa.zip>

   This is part of the following larger work.

   Patterson, Karen, 200806, Patterson, K.D. 2008. Vegetation Classification and Mapping at Colonial National Historical Park, Virginia. Technical Report NPS/NER/NRTR--2008/129. National Park Service. Philadelphia, PA..

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -76.835518

   East_Bounding_Coordinate: -76.489147

   North_Bounding_Coordinate: 37.285860

   South_Bounding_Coordinate: 37.190824

   Description_of_Geographic_Extent: Colonial National Historical Park and environs

3. What does it look like?

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

   Calendar_Date: Oct-2005

   Currentness_Reference: ground condition

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 (183)

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator

      Universal_Transverse_Mercator:

      UTM_Zone_Number: 18

      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.999600

      Longitude_of_Central_Meridian: -75.000000

      Latitude_of_Projection_Origin: 0.000000

      False_Easting: 500000.000000

      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000064
      Ordinates (y-coordinates) are specified to the nearest 0.000064
      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.
      The flattening of the ellipsoid used is 1/298.257222.
      

7. How does the data set describe geographic features?

   colo_veg_aa_2005

   attribute table from shapefile (Source: Virginia Department of Conservation and Recreation, Division of Natural Heritage)

   FID

   Internal feature number. (Source: ESRI)

   Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: ESRI)

   Coordinates defining the features.

   AA_OBS_ID

   Accuracy assessment point number (Source: NPS four letter park code plus unique number)

   NPS four letter park code plus unique number

8. What biological taxa does this data set concern?

   Taxonomy:

   Keywords/Taxon:

   Taxonomic_Keyword_Thesaurus: None

   Taxonomic_Keywords: Standardized National Vegetation Classification System

   Taxonomic_Keywords: vegetation classification

   Taxonomic_Keywords: alliance

   Taxonomic_Keywords: community association

   Taxonomic_Classification:

   Taxon_Rank_Name: Kingdom

   Taxon_Rank_Value: Plantae

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Virginia Department of Conservation and Recreation, Division of Natural Heritage

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Virginia Department of Conservation and Recreation, Division of Natural Heritage
   Ecologist
   217 Governor Street
   Richmond, Virginia 23219
   USA
   

   804-786-5990 (voice)
   

Why was the data set created?

This data set was created to identify the locations of sampling points used to assess the thematic accuracy of the Colonial National Historical Park vegetation map.

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: Oct-2005 (process 1 of 1)

   The number and distribution of accuracy assessment sampling points was determined by map class abundance and frequency as recommended in the USGS/NPS Vegetation Mapping protocols (The Nature Conservancy and Environmental Systems Research Institute 1994c), with one regional modification to accomodate the vegetation pattern seen in the park (Patterson 2008). A stratified random sampling approach was used, distributing the sampling effort across polygons representing natural or semi-natural vegetation greater than 0.5 ha. Polygons representing seven Anderson land-use classes were not included in the sample design: Beaches; Industrial and Commercial Complexes; Mixed Urban or Built-up Land; Other Urban or Built-up Land; Residential; Transportation, Communications, and Utilities; and Water. Four classes of cultural vegetation, Cultural Meadow, Dense Hardwood Regeneration, Mixed Successional Scrub, and Semipermanent Impoundment were also excluded from the accuracy assessment. These classes represent very distinct, intensively managed features that were easily delinated from aerial photography or classes with a few, very small polygons that were completely surveyed on-the-ground during the mapping phase of the project. Additionally, five map classes that naturally occur in small patches and were not mapped by photo interpretation, but through chance encounters in the field, were excluded from the sampling design: Coastal Plain Depression Wetland (Red Maple - Sweetgum - Willow Oak Type), Coastal Plain Depression Wetland (Swamp Tupelo Type), Coastal Plain Dry Calcareous Forest, Piedmont / Low Elevation Mixed Oak / Heath Forest, and Successional Sweetgum Forest. These map classes had very few (1-8) polygons and the polygons were mostly below minimum mapping unit (0.5 ha) and were completely surveyed on-the-ground during the mapping phase of the project. Three map classes that were created to indicate vegetation that may have formerly represented natural communities, but is now too altered to assign to a natural community classification, were excluded from the accuracy assessment. The polygons in these classes were mapped only due to chance encounters, were surveyed completely during the mapping phase of the project: Disturbed Calcareous Forest, Disturbed Depressional Wetland, Disturbed Seepage Swamp. One hundred and eighty-three randomly selected accuracy assessment sampling points were generated using the Random Point Generator v. 1.3 (Jenness 2005) in ArcView 3.3. All points were reviewed over topographic maps and aerial photos. Points were reassigned if the randomly selected point fell on a road, outside the park boundary or if there were potential access limitations. In August through October 2005, all 183 accuracy assessment points were located in the field by VADNH staff using a Garmin Map76S WAAS enabled GPS. Field staff determined the map class at the accuracy assessment point using a dichotomous key to the vegetation map classes and detailed vegetation descriptions.

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?

   Each accuracy assessment point is represented by one point in the shapefile. All points fall within vegetation map polygons.

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

   ESRI point geometry.

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)
   USGS/CSS/Core Science Analytics and Synthesis
   c/o USGS-NPS Vegetation Mapping Program Coordinator
   Denver Federal Center, Building 810, Room 8000, MS 302
   Denver, Colorado 80225
   

   (303) 202-4220 (voice)
   303-202-4219 (FAX)
   gs-b-npsveg@usgs.gov
   

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

   Downloadable Data

3. What legal disclaimers am I supposed to read?

   The U.S. Geological Survey and the National Park Service shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data and related graphics (if available) are not legal documents and are not intended to be used as such.

   The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. Any related graphics (if available) are intended to aid the data user in acquiring relevant data; it is not approriate to use the related graphics as data.

   The U.S. Geological Survey and the National Park Service gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from an U.S. Geological Survey and National Park Service servers and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. Mention of trade names or commercial products in this metadata report does not constitute endorsement or recommendation for use by the U. S. Department of the Interior, U. S. Geological Survey and National Park Service.

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

     Data format:	HTML
     Network links:	<http://biology.usgs.gov/npsveg/colo/index.html>

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 08-Apr-2008
Last Reviewed: 18-May-2010

Metadata author:

USGS/CSS/Core Science Analytics and Synthesis
c/o USGS-NPS Vegetation Mapping Program Coordinator
Denver Federal Center, Building 810, Room 8000, MS 302
Denver, Colorado 80225

(303) 202-4220 (voice)
303-202-4219 (FAX)
gs-b-npsveg@usgs.gov

Metadata standard:

FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata (FGDC-STD-001.1-1999)

Metadata extensions used:

• <http://www.nbii.gov/portal/server.pt/community/fgdc_metadata/255>