Land Cover for Wyoming

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. Where did the data come from?
  2. What changes have been made?
• 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: Land Cover for Wyoming

Abstract:

This data contains land cover (mostly vegetation types) for the entire state of Wyoming at 1:100000 scale. Attribute fields describe primary and secondary land cover, crown closure, wetlands, disturbance and other important land cover types occuring within the polygon. Only the fields for primary land cover and percentage of each polygon occupied by that land cover are complete in the coverage, but other attribute fields are populated when information was available.

The data is available for distribution as one statewide file or tiled into 56 separate files by USGS 1:100,000 quadrangle. The format for distribution is either ARC/INFO export format or ArcView shapefile.

1. How should this data set be cited?

   Analysis, Wyoming Gap, 19961201, Land Cover for Wyoming: University of Wyoming, Spatial Data and Visualization Center, Laramie, Wyoming.

   Online Links:

   • <URL:http://www.wygisc.uwyo.edu/24k/landcov.html>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -111.09334522

   East_Bounding_Coordinate: -103.88352708

   North_Bounding_Coordinate: 45.10795123

   South_Bounding_Coordinate: 40.95004394

3. What does it look like?

   <URL:http://www.wygisc.uwyo.edu/clearinghouse/images/gapveg.gif> (gif)

   primary land cover types for Wyoming, color-coded

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

   Calendar_Date: 1994

   Currentness_Reference: Publication date of sources

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

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):

      • Point (14710)
      • String (65543)
      • GT-polygon composed of chains (14710)

   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 .001. Longitudes are given to the nearest .001. Latitude and longitude values are specified in Decimal Degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is GRS1980.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.
      

7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview:

   Attributes assigned to each polygon describe primary and secondary cover types, the percent area of each polygon occupied by these types, as well as other important land cover types occuring in the polygon. Wetland type, crown closure of primary forest types, and disturbance (such as fire or logging) are also recorded and associated with main polygon attribute table.

   ArcView shapefile format: Additional files in Dbase format are available with additional attributes and descriptions for codes:

   covname.dbf:  Full names of primary/secondary/other cover type codes
   crown.dbf: Amount of crown closure (canopy) for primary forest types
   wetlands.dbf:  Description of wetland (or deep water type) occuring in
                  polygons, based on National Wetlands Inventory classification
   scene.dbf: Codes and names of TM scenes used to attribute the polygons
                  and delineate the polygon boundary. Also includes the path,
                  row, date, and source of the images, as well as the person(s)
                  responsible for processing, digitizing and labeling from the
                  scene.
   checker.dbf: Codes and names of persons involved in checking the polygon.
                 Includes the person's agency and date that they checked the
                 polygon.
   disturanc.dbf: description of 10 type of disturbance recorded
   source.dbf: citation of source used to attribute the land cover types
   

   ARC/INFO export file format: When the file is imported, eight additional INFO files are also imported:

   LANDCOV.NAME (same as covname.dbf above)
   LANDCOV.WETLANDS
   LANDCOV.SCENE
   LANDCOV.CHECKER
   LANDCOV.CHECKED
   LANDCOV.DISTURBANCE
   LANDCOV.SOURCE
   LANDCOV.DISPLAY
   LANDCOV.RELATE
   

   LANDCOV.DISPLAY is a lookup-table for displaying the land cover in ArcPlot. LANDCOV.RELATE is a relate file for performing relates (Links) between the coverage and the additional INFO files in ARC/INFO.

   Entity_and_Attribute_Detail_Citation: n/a

   land cover polygons

   This is the only entity or feature in this dataset. It is described by these attributes: PRIMARY, PRIM_PERCENT, SECONDARY, SEC_PERCENT, WETLANDS, OTHER, DISTURBANCE, SCENECODE, SOURCE, CHECKED, CHECKER (Source: n/a)

   PRIMARY

   Code for primary land cover type: type that covers the majority of the area of the polygon (Source: Land cover classifcation)

   Formal codeset
   Codeset Name:	codes for land cover types
   Codeset Source:	Codes described in lc_name.dbf file

   PRIM_PERCENT

   percent that primary cover type occupies in polygon (Source: n/a)

   Range of values
   Minimum:	0
   Maximum:	100

   SECONDARY

   Code for secondary land cover type: type that covers the 2nd largest area of the polygons (Source: land cover classification)

   Formal codeset
   Codeset Name:	codes for land cover types
   Codeset Source:	Codes described in lc_name.dbf file

   SEC_PERCENT

   percent that secondary cover type occupies in polygon (Source: n/a)

   Range of values
   Minimum:	0
   Maximum:	100

   PRIM_CROWN

   Amount of crown closure (canopy) for primary forest types (Source: interpretation from images)

   Formal codeset
   Codeset Name:	codes for crown closure
   Codeset Source:	Codes described in lc_crown.dbf file

   WETLANDS

   Most important wetland (or deep water type) occuring in the polygon (if any) (Source: n/a)

   Formal codeset
   Codeset Name:	codes for wetland types
   Codeset Source:	Codes described in lc_wetla.dbf file

   OTHER

   Code for other land cover type present in the polygon (Source: n/a)

   Formal codeset
   Codeset Name:	codes for land cover types
   Codeset Source:	Codes described in landcov.name file

   DISTURBANCE

   Disturbance found within within the polygon (if any) (Source: n/a)

   Formal codeset
   Codeset Name:	codes for disturbance types
   Codeset Source:	Codes described in lc_distu.dbf file

   SCENECODE

   Reference to the TM image scene used to add attributes to the polygon and delineate the polygon boundary (Source: n/a)

   Formal codeset
   Codeset Name:	codes for TM image scenes
   Codeset Source:	Codes described in landcov.scene file

   SOURCE

   Reference link to sources of information used to add attributes to the polygon (Source: n/a)

   Formal codeset
   Codeset Name:	codes for source references
   Codeset Source:	Codes described in lc_sourc.dbf file

   CHECKED

   Indication of whether or not the polygon attributes have been checked in the field (Source: n/a)

   Value	Definition
   0	Not field checked
   1	Field checked, updated
   2	Field checked, not updated

   CHECKER

   Name of the individual who field checked the polygon, if it was checked (Source: n/a)

   Formal codeset
   Codeset Name:	codes for names of checkers
   Codeset Source:	Codes and additional information described in lc_chker.dbf file

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Wyoming Gap Analysis

2. Who also contributed to the data set?

   Dr. William Reiners, Ken Driese, Rob Thurston, Dept. of Botany, University of Wyoming

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

   Data Manager
   Spatial Data and Visualization Center
   Box 4008 University Station
   Laramie, Wyoming 82071
   USA
   

   307-766-2735 (voice)
   n/a
   

   Hours_of_Service: 8 AM to 5 PM MST

The primary purpose of this data was to provide information on the geographic distribution of land cover (primarily vegetation types) for the Wyoming Gap Analysis project (WY-GAP). The secondary purpose of the data was to provide a variable (vegetation as habitat) for the purposes of mapping vertebrate species habitat associations for WY-GAP. This data may also be used for a variety of coarse (regional) scale landscape analysis/management purposes pertaining to land cover.

1. Where did the data come from?

   TM image (source 1 of 3)

   sources, Various, 1987-1993, Landsat Thematic Mapper Satellite Images:.

   Type_of_Source_Media: online

   Source_Contribution:

   The images were used for interpretation of land cover. 23 images were used across Wyoming. Name, path/row, date source, and individuals repsonsible for processing the scenes are available in files associated with this dataset. See the entity and attribute section for more details.

   WLI (source 2 of 3)

   Wyoming Dept. of Agriculture, Geologic Survey, 1987, Wyoming Land Inventory Map:.

   Type_of_Source_Media: online

   Source_Contribution:

   Interpretation of land cover for the area of southeastern Wyoming where there were no TM images available (at the time)

   SPOT image (source 3 of 3)

   Larry Munn, Dept. of Plant, Soil and Insect Scien, unknown, SPOT image:.

   Type_of_Source_Media: online

   Source_Contribution:

   Interpretation of land cover for the area around Torrington Wyoming where there was no TM image available (at the time)

2. What changes have been made?

   Date: 19-Jan-1991-1993 (change 1 of 4)

   Data from the TM images was resampled from orginial 30 m resolution to 100 m resolution and contrast stretched using a normalized contrast table and MIPS software. TM bands 3,4, and 5 were then exported to Arc/Info in ERDAS format and displayed as false colored images for interpretation. Additional sources such as the WLI map and the SPOT image were used to delineate polygon boundaries where TM images were not available in areas of southeastern Wyoming.

   Data sources used in this process:

   • TM image

   Date: 19-Jan-1992-1994. (change 2 of 4)

   Polygons were digitized on the computer screen by using a mouse to draw lines over the 3 band false color TM image. These polygons delineate relatively homogeneous spectral regions on the imagery. Polygons were subsequently edited and assigned attributes within the ARCEDIT environment by incorporating photointerpretation techniques, maps available from federal, state and local agencies, information from journal articles and graduate theses, conversations with field workers and field reconnaissance. A detailed description of the methods used for delineation and labeling of polygons is available upon request from the Botany Dept, University of Wyoming.

   Data sources used in this process:

   • TM image, WLI map, SPOT image

   Date: 1994 (change 3 of 4)

   Plots of the landcover map at a 1:100,000 scale were distributed to field personnel in different agencies for field checking of the primary land cover attribute. (See attribute accuracy section for more details). Corrections suggested from field checking were incorporated into the draft map, resulting in the first version of the map and database published in Jan. 1995.

   Date: 19-Jan-1996. (change 4 of 4)

   Corrections were made to polygons and attributes based on errors identified by users after initial distribution. Total of number of polygons in first version (14,753) was changed to 14,732 in the second version. Contact Ken Driese, coverage developer, for more information on these corrections (Dr. William Reiners office, Dept. of Botany, University of Wyoming). The most major attribute change was to polygon ID 19120, changed from primary 42001 (spruce-fir) to 32007 (Wyoming big sagebrush).

1. How well have the observations been checked?

   Based on informal field checking, the accuracy of the land cover data is 79.6%. The accuracy is not based on a formal quantative assessment. Field checking was performed by personnel from agencies such as the BLM, Forest Service, Fish and Wildlife Service, Natural Resource Conservation Service, Wyoming Game and Fish Department, and the Nature Conservancy, on a volunteer basis. There was no systematic sampling of polygons to be field-checked and because of the 100 hectare minimum mapping unit of the polygons, verifying the primary land cover type and other attributes cannot always be reliably done on the ground. Of a total of 14,690 polygons digitized for Wyoming, 1809 (12.3%) were checked in the field, and 1439 (79.6%) of these polygons were determined to be correct by the checkers.

   To attain a better estimate of accuracy, a formal statistical evaluation utilizing aerial videography validation techniques is in progress, and is due to be completed in 1998. The aerial videography may also provide training data for future updates of the land cover map.

2. How accurate are the geographic locations?

   The minimum mapping unit for upland cover types is 100 ha and 40 ha for water/riparian types, a level of generalization that was not intended to accurately portray accurate positional boundaries of vegetation. Polygons generally portray more than one cover type (primary, secondary and other), the actual boundaries between the different types being at too fine a scale to be captured at the the specified minimum mapping unit.

3. How accurate are the heights or depths?

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

   The minimum mapping unit for polygons in this coverage is 100 ha for upland cover types and 40 ha for water/wetland/riparian types. Because of the minimum mapping unit, rules of generalization have been applied to this dataset, and its attributes are completed for the level of detail that may be interpreted at the 100 ha and 40 ha minimum mapping units.

   All polygons include attributes for primary land cover and the percent of the polygon occupied by that cover, codes for the source of information from which the polygon was digitized, and codes identifying the digitizer. Other attributes may not be complete for all polygons, either because attributes did not apply to that particular polygon (primary crown cover does not apply to non-forested types), or attributes could not be filled for lack of information/restrictions of the minimum mapping unit.

   Approximately 88% of polygons have a secondary cover attribute and percent secondary cover attribute; 15% polygons have a percentage crown attribute; 21 have an other land cover attribute; 11% have a wetlands attribute and 2% have a disturbance attribute.

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

   All polygons are closed and adjacent polygons do not have identical attributes. Each polygon has one and only one label.

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

Access_Constraints: None.

Use_Constraints:

This dataset was produced with an intended application at the state or ecoregion level - geographic areas from several hundred thousand to millions of hectares in size. The data provide a course-filter approach to analyses, meaning that not every occurrence of animal habitat is mapped; only large, generalized distributions are mapped, based on the USGS 1:100,000 mapping scale in both detail and precision. Therefore, this dataset can be used appropriately for coarse-scale (> 1:100,000) applications, or to provide context for finer-level maps or applications.

Appropriate uses include:
1. statewide biodiversity planning;
2. regional and large area resource planning;
3. coarse-filter evaluation of potential impacts or benefits of major
projects/initiatives on biodiversity - such as utility or transportation
corridors, wilderness proposals, open space or recreation proposals;
4. environmental impact assessment for large projects
such as military activities;
5. education at all levels for both students and citizens.
Inappropriate uses of this data include:
1. Generating specific measurements from the data finer than the
nearest thousand hectares;
2. Establishing exact boundaries for regulation or acquisition;
3. Establishing definite presence or absence of any element;
4. Determining abundance, health, or condition of any element;
5. Establishing a measure of accuracy of any other data by
comparison with this dataset;
6. Combining this data with any other data finer than
1:100,000-scale for analysis;
7. Use of this data to map small areas (less than thousands of
hectares) typically requiring mapping resolution at 1:24,000-scale
and using aerial photographs or ground surveys;
8. Altering the data in anyway and redistributing it as a GAP product.

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

   Data Manager
   Spatial Data and Visualization Center
   Box 4008 University Station
   Laramie, Wyoming 82071
   USA
   

   307-766-2735 (voice)
   n/a
   

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

3. What legal disclaimers am I supposed to read?

   The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate used described in this metadata document. It is strongly recommended that this data is directly acquired from the distributor described above or from another U.S.G.S. Biological Resource Division server and not indirectly through other sources which may have changed the data in some way. This data was developed and is meant to be used at the 1:100,000-scale (or smaller scale) for the purpose of assessing the conservation status of vegetation types over large geographic regions. The distributor makes no claims as to the data's suitability for other purposes.

4. How can I download or order the data?

   Data format:	ARCE (Arc/Info export) (version 7.0.4) Size: 36.8
   Network links:	ftp.wygisc.uwyo.edu or <http://www.wygisc.uwyo.edu/clearinghouse>

   • Cost to order the data:

     No fees for downloading the data that is on-line. Some fees may be required to cover cost of tapes if data is required on tape media.

Dates:

Last modified: 08-Jun-1997

Metadata author:

Margo Berendsen
Box 4008 University Station
Laramie, Wyoming 82071
USA

307-766-2735 (voice)
meh@uwyo.edu

Metadata standard:

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