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?

   Greg Podniesinski, Pennsylvania Science Office of the Nature Conservancy, 20041206, Thematic Accuracy Assessment Points for the Association-level Vegetation Map of Valley Forge National Historical Park (VAFO).

   Online Links:

   • <http://biology.usgs.gov/npsveg/ftp/vegmapping/vafo/vafoaa.zip>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -75.472342

   East_Bounding_Coordinate: -75.417142

   North_Bounding_Coordinate: 40.121246

   South_Bounding_Coordinate: 40.079016

   Description_of_Geographic_Extent: Valley Forge 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: Sep-2001

   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 (308)

   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 0.000008
      Ordinates (y-coordinates) are specified to the nearest 0.000008
      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 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.
      

7. How does the data set describe geographic features?

   VAFO_VEG_AA_2005

   Accuracy Assessment sample plot locations for Valley Forge (Source: PSO-TNCNational Historic Site)

   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

   Unique ID that relates this spatial data layer to the AA Observations table in the PLOTS database. (Source: NPS)

   All IDs are prefixed with "VAFO" so an example ID is "VAFO.1"

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)
   • Greg Podniesinski, Pennsylvania Science Office of the Nature Conservancy

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Greg Podniesinski
   Pennsylvania Science Office of the Nature Conservancy
   Ecologist
   208 Airport Road
   Middletown, Pennsylvania 17057
   United States
   

   717-948-3842 (voice)
   c-gpodnies@state.pa.us
   

Why was the data set created?

The shapefile shows point locations for accuracy assesment observation points. Locations were determined using a Garmin III+ Gps unit

How was the data set created?

1. From what previous works were the data drawn?

   photos (source 1 of 1)

   International, Kucera, 200204, Spring 2002 False Color Infrared aerial photography, 1:12000 scale.

   Type_of_Source_Media: color ir aerial transparencies

   Source_Contribution: Aerial view of Valley Forge NHP

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

   Date: 2001 (process 1 of 1)

   Thematic Accuracy Assessment Field Methods (from the cross-referenced final report)

   Thematic accuracy assessment has several objectives including to assess the data's suitability for a particular application, to inform the map producers to learn more about data errors and improve the mapping process, and to conform to production standards.

   Accuracy assessment (AA) sampling design followed the guidelines provided in the NBS/NPS Vegetation Mapping Program (The Nature Conservancy 1994) manuals with respect to the number of AA points sampled and their distribution across park polygons. The sampling design called for 308 points across 24 polygon types during the 2001 field season. Natural and anthropogenic polygon types were included in the AA. AA sampling coordinates were selected by generating random points within the minimum and maximum easting and northing UTM coordinates of the park's extent. Points within 30 m of a polygon border were eliminated to avoid sampling within ecotones. If two or more points still remained in a polygon, one point was randomly chosen and the others discarded. In several of the larger polygons up to six AA points were selected. In the case of some smaller polygons, additional random point selection was required before a random point fell into those polygons. Also, in some polygons it was not possible to locate an AA point 30 m from a border, in which case the AA point was manually located equidistant from polygon borders.

   AA points were located in the field using a Garmin III Plus GPS unit. Data collection included accuracy assessment plot number and GPS location information, vegetation type at the AA point, vegetation type(s) within 50 m of the AA point, dominant species by strata, canopy closure, and rationale for classification. This data is stored in the PLOTS database (MS Aceess). Vegetation associations were identified using the vegetation key developed for the park. AA results were analyzed using a sample misclassification matrix. Overall accuracy, Kappa index and 90 % confidence intervals were calculated as described in the Accuracy Assessment Procedures-USGS/NPS Vegetation Mapping Program manual (The Nature Conservancy 1994).

   Person who carried out this activity:
   

   Greg Podniesinski
   Pennsylvania Science Office of the Nature Conservancy
   Ecologist
   208 Airport Road
   Middletwon, Pennsylvania 17057
   United States
   

   (717) 948-3842 (voice)
   c-gpodnies@state.pa.us
   

3. What similar or related data should the user be aware of?

   Greg Podniesinski, Pennsylvania Science Office of the Nature Conservancy, Stephanie Perles, Pennsylvania Science Office of the Nature Conservancy, Lesley Sneddon, NatureServe, and Bill Millinor, North Carolina State University Center for Earth Observation, 200412, Vegetation classification and mapping of Hopewell National Historic Site: Pennsylvania Science Office of the Nature Conservancy, Middletown, Pennsylvania.

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?

   Mean horizontal accuracy of thematic accuracy assessment points was 2.55 m +/- 1.067m STD

3. How accurate are the heights or depths?

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

   Locations for all 308 accuracy assessment points are included.

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

   ESRI Point Geometry exists.

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?

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/vafo/index.html>

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 22-Jul-2005
Last Reviewed: 16-Jun-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>