Spatial Vegetation Data 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?

   North Carolina State University - Center for Earth Observation; Pennsylvania Natural Diversity Inventory - East, The Nature Conservancy (Pennsylvania Science Office); Valley Forge National Historical Park, 20020901, Association-level Vegetation Map for Valley Forge National Historical Park (VAFO) in Pennsylvania.

   Online Links:

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

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -75.473051

   East_Bounding_Coordinate: -75.416067

   North_Bounding_Coordinate: 40.123300

   South_Bounding_Coordinate: 40.078468

   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: 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?

      Indirect_Spatial_Reference: Valley Forge National Historical Park, Valley Forge, PA

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (322)

   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_Map_2005

   vegetation attribute database (Source: none)

   FID

   Internal feature number. (Source: ESRI)

   Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: ESRI)

   Coordinates defining the features.

   FORM_CODE

   The formation code is a unique idenitifier for the formation level of the National Vegetation Classification System (NVCS). (Source: The Nature Conservacny)

   Formal codeset
   Codeset Name:	International Classification of Ecological Communities: Terrestrial Vegetation of the Northeastern United States. Pennsylvania and Ecoregion 61 Review Subset.
   Codeset Source:	The Nature Conservancy

   FORM_NAME

   The formation desciption is a unique description that is associated with the formation code and the formation level of the National Vegetation Classification System (NVCS). (Source: The Nature Conservacny)

   Formal codeset
   Codeset Name:	International Classification of Ecological Communities: Terrestrial Vegetation of the Northeastern United States. Pennsylvania and Ecoregion 61 Review Subset.
   Codeset Source:	The Nature Conservancy

   RECNO

   Series of sequentially assigned numbers to identify each polygon (Source: The Nature Conservancy)

   Unique identifier.

   CEGL

   The Community Element Global Code (CEGL) is the unique identifier for the association level of the NVCS. (Source: NPS)

   Formal codeset
   Codeset Name:	International Classification of Ecological Communities: Terrestrial Vegetation of the Northeastern United States. Pennsylvania and Ecoregion 61 Review Subset.
   Codeset Source:	The Nature Conservancy

   Assoc_Sci

   The NVC Scientific Name is the description associated with the CEGL code. (Source: NPS)

   Formal codeset
   Codeset Name:	International Classification of Ecological Communities: Terrestrial Vegetation of the Northeastern United States. Pennsylvania and Ecoregion 61 Review Subset.
   Codeset Source:	The Nature Conservancy

   Assoc_Com

   The NVC English Name is the description associated with the CEGL code. (Source: NPS)

   Formal codeset
   Codeset Name:	International Classification of Ecological Communities: Terrestrial Vegetation of the Northeastern United States. Pennsylvania and Ecoregion 61 Review Subset.
   Codeset Source:	The Nature Conservancy

   Local_Name

   Common Name (Park-specific) is a local name identified by the Pennsylania Office of The Nature Conservancy (Source: NPS)

   Formal codeset
   Codeset Name:	International Classification of Ecological Communities: Terrestrial Vegetation of the Northeastern United States. Pennsylvania and Ecoregion 61 Review Subset.
   Codeset Source:	The Nature Conservancy

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)
   • North Carolina State University - Center for Earth Observation; Pennsylvania Natural Diversity Inventory - East, The Nature Conservancy (Pennsylvania Science Office); Valley Forge National Historical Park

2. Who also contributed to the data set?

   Frank Koch - CEO Greg Podniesinski - PSO

3. To whom should users address questions about the data?
   Valley Forge National Historical Park
   GIS Specialist
   P. O. Box 953
   Valley Forge, PA 19482-0953
   

   610-783-1000 (voice)
   610-783-1053 (FAX)
   

   Hours_of_Service: 0800 - 1700

Why was the data set created?

To develop a vegetation database for VAFO to the association level of the National Vegetation Classification System and based on the USGS-NPS Vegetation Mapping Program protocals.

How was the data set created?

1. From what previous works were the data drawn?

   photos (source 1 of 1)

   Air Photographics, Incorporated, 19990912, 1:6000 color-infrared photo-transparancies of Valley Forge National Historical Park, September 12, 1999.

   Type_of_Source_Media: photo-transparency

   Source_Scale_Denominator: 6000

   Source_Contribution: Homogeneous polygons of vegetation and landcover.

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

   Date: Dec-1999 - 200104 (process 1 of 2)

   North Carolina State University - Center for Earth Observation (CEO) staff scanned the photos with an EPSON Expression 836 XL desktop scanner using Adobe Photoshop 5.0 software at a resolution of 600 dots per inch. The scanned images were saved as Tagged-Image File Format files that were subsequently converted to ERDAS Imagine image file (*.img) format.

   Orthorectification, the process of removing radial tilt and relief distortion from aerial photographs and the first step in creating a photo mosaic, was performed using ERDAS Imagine software. CEO staff used two black and white digital orthophoto quarter quadrangles (DOQQs) obtained from the Pennsylvania Geospatial Data Clearinghouse to provide the X- and Y-coordinate references for orthorectifying the scanned photography. The two DOQQs were mosaicked into a single image and reprojected to match existing park data layers.

   Two USGS digital elevation models (DEMs) obtained from the Pennsylvania Geospatial Data Clearinghouse were used to provide the elevation data required for orthorectification. The DEMs were reprojected to match existing park data layers. They were then resampled from 30-meter to 10-meter pixel resolution using a cubic convolution algorithm. The resultant DEMs were mosaicked into a single DEM.

   CEO staff orthorectified each scanned photo-transparency individually using ERDAS Imagine. Using the DOQQs as a base, between seven and twelve ground control points were spread across each image and the elevation for each point was obtained from the DEM. Typical points included visible features on the DOQQs and photos. In the final step of this process, each image was resampled into an orthophoto using a cubic convolution interpolation method.

   A single orthorectified mosaic was created from the individual orthorectified images using ERDAS Imagine software.

   CEO staff delineated formation level vegetation classes using ArcMap 8.0.1 software produced by Environmental Systems Research Institute (ESRI) to heads-up digitize homogeneous polygons using the orthorectified photo mosaic as a backdrop. Before starting the on-screen classification, CEO staff worked with the Pennsylvania Science Office of The Nature Conservancy (PSO) to develop a preliminary list of formations and draft associations based on The Nature Conservancy's Terrestrial Vegetation of the United States. Vegetation, polygons were delineated based on clear differences in stand height, color/spectral differences, (and thus, at least in theory, species) composition, and texture. The interpreter used ancillary data--hard copy stereo pairs, DOQQs, and geospatial data provided by VAFO--to assist in delineating areas of homogeneous vegetation. The minimum mapping unit was approximately 0.5 acres although smaller distinctive areas were delineated to provide a basis for association level mapping. To ensure that all areas within the park were covered, one full polygon outside the park boundary was mapped.

   Upon completion of the formation level classification, CEO staff created a draft association level vegetation map using a classification scheme based on The Nature Conservancy's Terrestrial Vegetation of the United States and association level classes developed by PSO. An ERDAS Stereo Analyst workstation equipped with a color monitor with a high refresh rate and an emitter box affixed to the top of the monitor was used to view the orthorectified images in stereo. The interpreter wears a pair of battery-powered goggles that flash 115 times per second. Emitter waves strike the goggles and, with the high refresh rate of the monitor, allow the interpreter to view a photo pair on-screen in stereo. Once the workstation and working parameters were established, the formation level vegetation database was imported into ERDAS Stereo Analyst. The interpreter viewed the formation level polygons overlaid on each stereo pair to delineate association level polygons and assign preliminary association classes based on the formation and environmental factors including topography, aspect, individual species, and vegetation height. The resulting draft association level vegetation database was exported to an ESRI shapefile.

   Person who carried out this activity:
   

   North Carolina State University - Center for Earth Observation
   NCSU Campus Box 7106
   Raleigh, NC 27695-7106
   

   919-515-3430 (voice)
   919-515-3439 (FAX)
   

   Hours_of_Service: 0900 - 1700

   Data sources used in this process:

   • photos

   Data sources produced in this process:

   • draft association level map

   Date: Apr-2001 - 200206 (process 2 of 2)

   The PSO staff developed a vegetation plot sampling design in spring 2000 following USGS/NPS Vegetation Mapping Program guidelines. PSO allocated plots to each of the 17 vegetation types included on the draft association level map, with replicate plots assigned over each type's environmental range. The sampling design called for three to five plots per association and a minimum of 75 plots.

   The PSO staff placed plots subjectively so that they would be most representative of the mapped vegetation units. Additional plots were established when field personnel encountered a vegetation type that was not included in the classification scheme or that was not well known.

   The PSO staff collected data from a total of 80 plots between May and October 2000. Mount Joy was sampled intensively in May and June 2000. Between July 1 and mid-October 2000, field teams sampled grasslands throughout the park (with assistance from PSO staff botanist John Kunsman); forested sections of Mount Misery; forested, shrubland and grassland areas north of the Schuylkill River; and forested areas between Route 23 and the Schuylkill River.

   Based on this fieldwork, PSO staff edited some of the draft association level polygons. As a result, the final association level vegetation map has 69 fewer polygons than the draft association level database.

   Person who carried out this activity:
   

   Greg Podniesinski
   Pennsylvania Natural Diversity Inventory - East, The Nature Conservancy (Pennsylvania Science Office)
   Community Ecologist
   208 Airport Drive
   Middletown, PA 17057
   

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

   Hours_of_Service: 0900 - 1700

   Data sources used in this process:

   • draft association level map

   Data sources produced in this process:

   • final association level map

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

   National Park Service Northeast Region, Pennsylvania Science Office of The Nature Conservancy, 2005, Vegetation Classification and Mapping of Valley Forge National Historical Park, Technical Report NPS/NER/NRTR--2005/028.

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?

   The CEO staff calculated thematic accuracy of the database based on data collected by PSO staff at 308 plots collected during the 2001 and 2002 field seasons. Based on data collected at these plots, CEO staff estimates that the overall thematic accuracy of the database is 77.92 percent. At a 90 percent confidence interval, the estimated minimum overall thematic accuracy is 73.87 percent and the estimated maximum is 81.97 percent. Based on hypothesis testing, the final association level classification meets the minimum overall thematic accuracy of 80 percent specified in NPS vegetation mapping protocols.

   The most prevalent errors in the association level vegetation map were caused by inability to distinguish grasslands from croplands and late successional from climax forests.

2. How accurate are the geographic locations?

   The database is based on an orthorectified photo mosaic. Horizontal positional accuracy of the orthorectified photo mosaic meets Class 1 National Map Accuracy Standards in the X-coordinate direction and Class 2 National Map Accuracy Standards in the Y-coordinate direction with root mean square errors of 1.18 meters and 2.89 meters, respectively.

3. How accurate are the heights or depths?

   None

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

   The minimum mapping unit was approximately 0.5 acres although smaller distinctive areas were delineated. To ensure that all areas within the park were covered, one full polygon outside the park boundary was mapped.

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

   ESRI shapefile with polygon geomerty. Imported into a geodatabase to check topology rules and then exported as a shapefile.

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?

   Valley Forge NHP Final Association Level Vegetation Classification

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: 09-Jan-2006
Last Reviewed: 17-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>