USGS:Biology Biological Informatics Program Vegetation Characterization Program Walnut Canyon National Monument Accuracy Assessment FAQ Metadata

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?

Title: Accuracy Assessment Points: Walnut Canyon National Monument

Abstract:

This spatial dataset in ESRI Coverage format maps accuracy assessment point locations for the vegetation map at Walnut Canyon National Monument and in the surrounding environs as part of the National Vegetation Mapping Program.

1. How should this data set be cited?

   Thomas, Kathryn, Anderson, Becci Dale , and (comp.), Monica Hansen , 2004, Accuracy Assessment Points: Walnut Canyon National Monument.

   Online Links:

   • <http://biology.usgs.gov/npsveg/waca/index.html#accuracy_assessment_info>

   This is part of the following larger work.

   M. Hansen, J. Coles, K.A. Thomas, D. Cogan, M, 2004, USGS-NPS National Vegetation Mapping Program: Walnut Canyon National Monument, Arizona, Vegetation Classification and Distribution, Final Project Report.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -111.562630

   East_Bounding_Coordinate: -111.438317

   North_Bounding_Coordinate: 35.216440

   South_Bounding_Coordinate: 35.137473

   Description_of_Geographic_Extent: Walnut Canyon National Monument and the environs.

3. What does it look like?

   <http://biology.usgs.gov/npsveg/waca/images/wacaaa.pdf> (PDF)

   371 kbyte file showing vegetation associations and location of accuracy assessment points

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

   Calendar_Date: Aug-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 (353)
      • Point (4)

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator

      Universal_Transverse_Mercator:

      UTM_Zone_Number: 12

      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.999600

      Longitude_of_Central_Meridian: -111.000000

      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 0.000016
      Ordinates (y-coordinates) are specified to the nearest 0.000016
      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?

   waca_aapts.pat

   This is a listing of all accuracy assessment point locations within the Walnut Canyon National Monument project area (Source: User defined)

   FID

   Internal feature number. (Source: ESRI)

   Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: ESRI)

   Coordinates defining the features.

   AREA

   Area of feature in internal units squared. (Source: ESRI)

   Area is always zero for point coverages. Values are automatically generated.

   PERIMETER

   Perimeter of feature in internal units. (Source: ESRI)

   Perimeter is always zero for point coverages. Values are automatically generated.

   WACA_AAPTS#

   Internal feature number. (Source: ESRI)

   Sequential unique whole numbers that are automatically generated.

   WACA_AAPTS-ID

   User-defined feature number. (Source: ESRI)

   Sequential unique whole numbers that are automatically generated.

   X-COORD

   The geographical coordinates for UTM Easting (x-coordinate) collected at each accuracy assessment field point in NAD83 Zone12 using Garmin 45XL. (Source: The Universal Transverse Mercator (UTM) Grid USGS Fact Sheet 077-01 (August 2001) <http://erg.usgs.gov/isb/pubs/factsheets/fs07701.html>)

   Range of values
   Minimum:	449105
   Maximum:	460171
   Units:	meters

   Y-COORD

   The geographical coordinates for UTM Northing (y-coordinate) collected at each accuracy assessment field point in NAD83 Zone12 using Garmin 45XL. (Source: The Universal Transverse Mercator (UTM) Grid USGS Fact Sheet 077-01 (August 2001) <http://erg.usgs.gov/isb/pubs/factsheets/fs07701.html>)

   Range of values
   Minimum:	3888476
   Maximum:	3896681
   Units:	meters

   WACA_AAPTS

   Accuracy assessment points developed in the sampling design as a unique identifier for each polygon sampled. (Source: User Defined)

   Range of values
   Minimum:	1-10
   Maximum:	X15
   Units:	letter and number

8. What biological taxa does this data set concern?

   Taxonomy:

   Keywords/Taxon:

   Taxonomic_Keyword_Thesaurus: None

   Taxonomic_Keywords: plant communities

   Taxonomic_Classification:

   Taxon_Rank_Name: Kingdom

   Taxon_Rank_Value: Plantae

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Kathryn Thomas
   • Becci Dale Anderson
   • Monica Hansen (comp.)

2. Who also contributed to the data set?

3. To whom should users address questions about the data?

   Kathryn A. Thomas
   USGS-SBSC-Colorado Plateau Research Station
   Project Leader, Vegetation Scientist
   U.S. Geological Survey
   Flagstaff, Arizona 86001
   USA
   

   928.556.7327 (voice)
   928.556.7500 (FAX)
   Kathryn_A_Thomas@usgs.gov
   

   Hours_of_Service: 8:00 a.m. to 5:00 p.m. (Arizona time), Monday through Friday

   Contact_Instructions: E-mail

This data set was developed as part of the accuracy assessment sampling design for the vegetation map at Walnut Canyon National Monument and the surrounding environs. Points were developed to lead the field sampling and to determine if mapped polygons were correctly assigned in the field.

1. From what previous works were the data drawn?

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

   Date: 2001 (process 1 of 1)

   Prior to the sample selection design, topology and data structure of the coverage were checked by running a check for node errors and label errors in the GIS dataset. The GIS dataset was also dissolved, removing polygon boundaries when adjoining polygons have the same value using GIS. Reference point locations were then selected for each plant association/map class based on the total cover of each class in the mapping area, where plant associations with more cover had more reference points assigned, and vice versa. The number of polygons to be sampled was determined by the number of polygons in each vegetation class and the total area of each vegetation class of the spatial vegetation dataset. A table was built listing all vegetation types, the number of polygons and area in hectares for each vegetation type, and the number of polygons to be sampled. Randomization was ensured through creating a database table containing random numbers that were randomly assigned to the polygons. Randomly assigned polygons were sorted in ascending numeric order by the vegetation code and then by random numbers to list all vegetation types together. Only rows of predetermined sample number for each map class were retained. In addition to the number of polygons that must be sampled of each type, there were from 5 to 10 extra polygons included in the random sample of polygons in the case that the original polygons could not be reached. Of the 500 reference points initially chosen, 355 points were sampled in the field in the first round of sampling and 131 in the second round of sampling. Some accuracy assessment points were discarded from the initial round of sampling due to multiple accuracy assessment points occurring within a single polygon in the final vegetation map. In this case, the accuracy assessment point assessed in the initial round of sampling that contained the largest area of the polygon was selected as the point used for the final round of accuracy assessment. The first phase of sampling used reference points chosen to sample polygons greater than the minimum mapping unit (MMU) of 0.5 hectares; however, if not enough samples of the map class were available in polygons greater than the MMU, polygons less than the MMU were then sampled. In polygons greater than the MMU, reference point coordinates were assigned randomly in the polygon with a 5-meter buffer to the keep sample points away from stand boundaries. In polygons that were less than the MMU, the centroid of the polygon was used for the sampling coordinates to minimize edge effects from adjacent polygons. In the second round of sampling all randomized polygons were selected for accuracy assessment. However, sampling points were allocated differently depending on two types of polygons: polygons that were equal to or greater than 0.5 hectares in area (the MMU) and polygons that were less than 0.5 hectares in area (< the MMU). Polygons that were equal to or greater than 0.5 hectares contained a 5-meter buffer from the outside polygon edge to be sure that none of the randomly placed points were placed extremely close to the edge of the polygon. Then, random points were assigned using a random point generator to add one random point to each polygon (Random Point Generator v.1.1, available at www.ESRI.com). Polygons that were less than 0.5 hectares in area had the centroid selected as the sampling points. Performing a cross-dataset query ensured the centroid of each polygon even in oddly shaped polygons (such as a crescent moon shape). The MS Excel file of the UTMs was exported as a text file and formatted as an ArcInfo generate file. The points coverage was then created using ArcToolbox generate.

   Person who carried out this activity:
   

   Kathryn Thomas
   USGS-SBSC-Colorado Plateau Research Station
   Project leader
   U.S. Geological Survey
   Flagstaff, Arizona 86001
   USA
   

   928.556.7327 (voice)
   928.556.7500 (FAX)
   Kathryn_A_Thomas@usgs.gov
   

   Hours_of_Service:

   8:00 a.m. to 5:00 p.m. (Mountain Standard Time Zone), Monday through Friday

   Contact_Instructions: E-mail

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

   Kathryn Thomas, U.S. Geological Survey, Southwest Bi, 2004, A USGS-NPS Vegetation Mapping Program: Walnut Canyon National Monument, Arizona, Vegetation Classification and Distribution. Technical Report FY 2003..

1. How well have the observations been checked?

   Dataset was quality checked in a spatial environment and through reviewing data entry.

2. How accurate are the geographic locations?

   Visual inspection was preformed on the dataset to ensure accuracy of all sampling locations

3. How accurate are the heights or depths?

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

   Data collection is complete with no exclusions

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

   Dataset was quality checked by visually inspecting the dataset in a geographic information system (GIS).

Are there legal restrictions on access or use of the data?

Access_Constraints: None

Use_Constraints:

This data was compiled for government use and represent the results of data collection/processing for a specific USGS/BRD activity/project. The USGS/BRD makes no representation as to the suitability or accuracy of this data for any other purpose and disclaims any liability for errors that the data may contain. As such, it is only valid for its intended use, content, time, and accuracy specifications. While there are no explicit constraints on the use of this data, please exercise appropriate and professional judgment in the use and interpretation of this data. Acknowledgement of the originating agencies would be appreciated in products derived from this data.

1. Who distributes the data set? (Distributor 1 of 1)

   USGS-NPS Vegetation Mapping Program Coordinator
   U.S. Geological Survey, Center for Biological Informatics, MS 302, Room 8000, Building 810, Denver Federal Center
   Denver, Colorado 80225
   USA
   

   (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/waca/index.html#accuracy_assessment_info>

   • Cost to order the data: None

Dates:

Last modified: 10-Feb-2004
Last Reviewed: 08-Nov-2007

Metadata author:

USGS-NPS Vegetation Mapping Program Coordinator
U.S. Geological Survey, Center for Biological Informatics, MS 302,
Room 8000, Building 810, Denver Federal Center
Denver, Colorado 80225
USA

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

Metadata standard:

FGDC-STD-001.1-1999 Content Standard for Digital Geospatial Metadata, 1998 Part 1: Biological Data Profile, 1999 (FGDC-STD-001-1998)

Metadata extensions used:

• <http://metadata.nbii.gov/portal/community/Communities/Toolkit/Metadata/FGDC_Metadata/>