Land Cover Trends Dataset, 1973-2000 -- 07. Central California Valley Ecoregion

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: U.S. Geological Survey Land Cover Trends Project
Publication_Date: 2014
Title: Land Cover Trends Dataset, 1973-2000 -- 07. Central California Valley Ecoregion
Edition: 1.0
Geospatial_Data_Presentation_Form: ERDAS Imagine (.img) format
Larger_Work_Citation:
Originator: Christopher E. Soulard
Originator: William Acevedo
Originator: Roger F. Auch
Originator: Terry L. Sohl
Originator: Mark A. Drummond
Originator: Benjamin M. Sleeter
Originator: Daniel G. Sorenson
Originator: Steve Kambly
Originator: Tamara S. Wilson
Originator: Janis L. Taylor
Originator: Kristi L. Sayler
Originator: Michael P. Stier
Originator: Christopher A. Barnes
Originator: Steve C. Methven
Originator: Thomas R. Loveland
Originator: Rachel Headley
Originator: Mark S. Brooks
Publication_Date: 2014
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Series_Name: Data Series
Issue_Identification: DS 844
Publication_Information:
Publication_Place: Reston, VA
Publisher: U.S. Geological Survey
Online_Linkage: <http://dx.doi.org/10.3133/ds844/ds844>
Online_Linkage: <http://pubs.usgs.gov/ds/844>
Description:
Abstract:
The U.S. Geological Survey (USGS) Land Cover Trends Project has developed a series of land-use/land-cover datasets that cover the conterminous United States. Land-use/land-cover data consist of 2,688 sample blocks randomly selected from a geographic strata defined by 84 Level III EPA ecoregions. For each sample block, land-use/land-cover maps are available for five dates: (1) 1973, (2) 1980, (3) 1986, (4) 1992, and (5) 2000. The land-use/land-cover maps were interpreted manually from Landsat MSS, TM, and ETM+ imagery. The resulting land-use/land-cover datasets have a 60-meter minimum mapping unit. The projection of these data is Albers Conical Equal Area, NAD 1983. The files are named after the stratified sampling scheme, and the filenames include the name and number of the ecoregion and the sample-block number. These raster digital data are organized by ecoregion, and are available in the ERDAS Imagine (.img) format.

This metadata file describes the data for ecoregion 07, Central California Valley Ecoregion. The 48 sample blocks in this ecoregion are numbered 0016, 0018, 0032, 0035, 0057, 0061, 0067, 0082, 0099, 0126, 0128, 0133, 0147, 0157, 0162, 0190, 0198, 0206, 0209, 0213, 0228, 0237, 0241, 0244, 0256, 0258, 0262, 0264, 0271, 0285, 0294, 0301, 0310, 0311, 0327, 0331, 0343, 0345, 0361, 0367, 0382, 0389, 0396, 0397, 0410, 0426, 0449, and 0452.

Purpose:
The Land Cover Trends Project was designed to (1) map the historical state of the nation's land surface between 1973 and 2000, (2) analyze patterns, rates, and trends in land-use/land-cover change, and (3) assess the causes and potential consequences of land change across the country. The research used EPA Level III ecoregions defined for the conterminous United States as the geographic framework for analysis. A sampling strategy was used in this assessment because sampling was a much more cost efficient method for characterizing land-use/land-cover change over as large an area as the United States. The sampling strategy used a stratified random sample of 2,688 blocks. For each Level III EPA ecoregion, a random sample of square blocks was independently selected for each strata analyzed, and researchers manually interpreted Landsat MSS, TM, and ETM+ imagery for five dates (1973, 1980, 1986, 1992, and 2000) to create change estimates for four intervals (1973-1980, 1980-1986, 1986-1992, and 1992-2000). The USGS Land Cover Trends Dataset was created to understand the geographic variability and characteristics of land-use/land-cover change in the conterminous United States between 1973 and 2000 and to provide a scientific foundation for assessing the environmental consequences of land change. More than 60 scientific papers have been published as of January 2014, and the results have been the basis for collaborative studies of the environmental consequences of change with scientists from many organizations, including USGS, NASA, NOAA, EPA, NSF, USFWS, and academia.
Time_Period_of_Content:
Time_Period_Information:
Multiple_Dates/Times:
Single_Date/Time:
Calendar_Date: 1973
Single_Date/Time:
Calendar_Date: 1980
Single_Date/Time:
Calendar_Date: 1986
Single_Date/Time:
Calendar_Date: 1992
Single_Date/Time:
Calendar_Date: 2000
Currentness_Reference: Date of Landsat scenes
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -2228955.75
East_Bounding_Coordinate: -2030315.13
North_Bounding_Coordinate: 2216582.00
South_Bounding_Coordinate: 1569582.63
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: land-use/land-cover change
Theme_Keyword: land-use change
Theme_Keyword: land-cover change
Theme_Keyword: land use
Theme_Keyword: land cover
Theme_Keyword: Landsat
Theme_Keyword: land change
Theme_Keyword: land cover trends
Place:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Conterminous United States
Theme_Keyword: United States
Theme_Keyword: Level III Ecoregions
Theme_Keyword: Omernik Ecoregions
Theme_Keyword:
Central California Valley
Stratum:
Place_Keyword_Thesaurus: None
Place_Keyword: ground surface
Temporal:
Place_Keyword_Thesaurus: None
Place_Keyword: 1973
Place_Keyword: 1980
Place_Keyword: 1986
Place_Keyword: 1992
Place_Keyword: 2000
Place_Keyword: late 20th century
Access_Constraints:
There are no legal prerequisites or restrictions for accessing the data.
Use_Constraints:
There are no legal prerequisites for using the data. The USGS only cautions that users understand the limits of these data before proceeding with personal, academic, and/or governmental use. A statement of the data source when citing, copying, or reprinting USGS data or images is requested.

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 display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein.

Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U. S. Government.

Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kristi L. Sayler
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing and physical address
Address: USGS/EROS
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6058
Contact_Facsimile_Telephone: 605-594-6529
Contact_Electronic_Mail_Address: sayler@usgs.gov
Contact_Instructions:
The USGS point of contact will answer questions relating to the data display and download of the data. For questions regarding data content and quality, refer to: <http://landcovertrends.usgs.gov> or email: lci@usgs.gov
Data_Set_Credit:
U.S. Geological Survey Land Cover Trends Project
Native_Data_Set_Format:
ERDAS Imagine file format
Native_Data_Set_Environment:
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
A traditional accuracy assessment was not conducted for interpreted blocks or the corresponding change images for each interval. However, quality-assurance/quality-control measures consisted of a formal block review conducted by the national research team where each land-use/land-cover date for each sample block was visually inspected for errors and informally compared to ancillary data. Where blocks bordered one another, an examination of land-use/land-cover adjacency was also conducted. The image interpreter was required to correct all errors following each review and document the corrections that were made.
Logical_Consistency_Report:
See the attribute accuracy report.
Completeness_Report:
Data are limited to sample blocks randomly selected within each ecoregion strata. The image dates (1973, 1980, 1986, 1992, and 2000) do not necessarily reflect the actual date of the Landsat image used in the interpretation process. These dates represent the core date, or center point, that each image represents. Image dates rarely deviated outside of +/-1 year from these core dates, although some exceptions exist. A minimum mapping unit of 60 meters was used for this study. Features that had ground footprints less than 60 meters wide were not mapped. For instance, high-contrast features such as roads that have ground dimensions of less than 60 meters wide were not mapped.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Horizontal positional accuracy is consistent with the Landsat Program since land-use/land-cover interpretations were derived from Landsat MSS, TM, and ETM+ imagery.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report: N/A
Lineage:
Process_Step:
Process_Description:
For each sample block, five dates of Landsat imagery were interpreted to map land use and land cover. The classification system consisted of 11 general land-use/land-cover classes (Water, Developed, Mechanically disturbed, Mining, Barren, Forest, Grassland/Shrubland, Agriculture, Wetland, Nonmechanically disturbed, Ice/snow). Land-use/land-cover delineation of each sample block began with the creation of a baseline reference land-use/land-cover dataset. The 1992 date was usually the starting point due to the availability of the 30-meter-resolution 1992 National Land Cover Data (NLCD). The more detailed NLCD classes were first aggregated to match the more general land-use/land-cover classification scheme used by the Land Cover Trends Project. The NLCD data were then manually edited on the computer screen using Erdas Imagine software, using on-screen interpretation methods while looking at 1992 Landsat TM data and also at various aerial photographs and geospatial data, which served as interpretation aids; a list of ancillary data is included in the accompanying document entitled "Land Cover Trends Dataset, 1973-2000" (available at <http://pubs.usgs.gov/ds/844/pdf/ds844.pdf>). This editing (that is, cleanup) procedure was done because NLCD data were created using automated image processing procedures at different scales (multistate blocks) and were not meant for use in local-scale assessments. A minimum mapping unit of 60 meters was used to guide delineations, and so features having ground footprints less than 60 meters wide were not mapped. Thus, the mapping excluded high-contrast features such as roads, which may have a distinct spectral signature but have ground dimensions of less than 60 meters. Land cover for the 1973, 1980, 1986, and 2000 periods was then backward- or forward-classified using the 1992 land-use/land-cover data as the template. Creation of the 2000 land-use/land-cover product, for example, began by making an exact copy of the 1992 land-use/land-cover product, which served as a baseline for the 2000 land-use/land-cover product. Changes between 1992 and 2000 were identified and then manually edited into the copied image by linking the 1992 Landsat imagery and the 2000 Landsat imagery, using the ERDAS Imagine geospatial-data authoring system. Each analyst panned through the entire sample block, examining the 1992 and 2000 Landsat imagery and any relevant aerial photography for valid land-use/land-cover changes between the two dates. Any land-use/land-cover changes identified were manually digitized on-screen, and the land cover was attributed on the 2000 land-use/land-cover map file. Upon completion of the 2000 land-use/land-cover product, the same procedures were used to create the 1986, 1980, and 1973 land-use/land-cover products, using 1992 to backward-classify change in 1986, and so forth. This manual process eliminated errors that can occur when change analyses are performed between independently created land-use/land-cover products. Because only manually identified, delineated, and coded land-use/land-cover changes were analyzed during this phase, classification errors were greatly reduced.

Sample blocks have dimensions of either 10 x 10 kilometers or 20 x 20 kilometers. Exceptions exist only where slivers were added along a coastline or in international boundary areas. Such sliver blocks have a file name that reflects adjacency to another block, and, therefore, the dimensions of the sliver sample blocks vary. Pixels were classified using a 60-meter minimum mapping unit. Interpreters classified objects that were discernible at the Landsat pixel resolution. All pixel values were assigned a value (between '1' and '11') that indicated the land-use/land-cover class.

Landsat imagery are not included as part of this release of the Land Cover Trends Dataset, but the image year is listed in the metadata to support approximate replication of the land-use/land-cover output.

Source_Used_Citation_Abbreviation: Landsat MSS, TM, and ETM
Process_Date: 2002-2010
Source_Produced_Citation_Abbreviation: Land Cover Trends
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kristi L. Sayler
Contact_Organization:
U.S. Geological Survey
Contact_Position: Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: USGS/EROS
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6058
Contact_TDD/TTY_Telephone: NA
Contact_Facsimile_Telephone: 605-594-6529
Contact_Electronic_Mail_Address: sayler@usgs.gov
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 167
Column_Count: 167
Vertical_Count: 1
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Albers Conical Equal Area
Albers_Conical_Equal_Area:
Standard_Parallel: 29.500000
Standard_Parallel: 45.500000
Longitude_of_Central_Meridian: -96.000000
Latitude_of_Projection_Origin: 23.000000
False_Easting: 0.000000
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 60.000000
Ordinate_Resolution: 60.000000
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137.000000
Denominator_of_Flattening_Ratio: 298.257222
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: Ecoregion Sample Block Layer
Entity_Type_Definition: Land Cover Trends
Entity_Type_Definition_Source: Land Cover Trends Dataset, 1973-2000
Attribute:
Attribute_Label: Count
Attribute_Definition:
A nominal integer value that designates the number of pixels that have each value in the file; histogram column in ERDAS Imagine raster attributes table
Attribute_Definition_Source: Land Cover Trends
Attribute_Domain_Values:
Range_Domain: Integer
Range_Domain_Minimum: 0
Range_Domain_Maximum: 27,889
Attribute_Units_of_Measure: Integer counts of pixels
Attribute_Measurement_Resolution: 1
Attribute:
Attribute_Label: Value
Attribute_Definition:
Land-use/land-cover class code value.
Attribute_Definition_Source: Land Cover Trends
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 0 - Unclassified
Enumerated_Domain_Value_Definition:
Areas not classified by interpreter, treated as NoData in statistics.
Enumerated_Domain:
Enumerated_Domain_Value: 1 - Water
Enumerated_Domain_Value_Definition:
Areas persistently covered with water, such as streams, canals, lakes, reservoirs, bays, or oceans.
Enumerated_Domain_Value_Definition_Source:
Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 2 - Developed
Enumerated_Domain_Value_Definition:
Areas of intensive use with much of the land covered with structures or anthropogenic impervious surfaces (e.g., high-density residential, commercial, industrial, roads, etc.) or less intensive uses where the land cover matrix includes both vegetation and structures (e.g., low-density residential, recreational facilities, cemeteries, parking lots, utility corridors, etc.), including any land functionally related to urban or built-up environments (e.g., parks, golf courses, etc.).
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 3 - Mechanically disturbed
Enumerated_Domain_Value_Definition:
Land in an altered and often unvegetated state that, due to disturbances by mechanical means, is in transition from one cover type to another. Mechanical disturbances include forest clear-cutting, earthmoving, scraping, chaining, reservoir drawdown, and other similar human-induced changes.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 4 - Mining
Enumerated_Domain_Value_Definition:
Areas with extractive mining activities that have a significant surface expression. This includes (to the extent that these features can be detected) mining buildings, quarry pits, overburden, leach, evaporative, tailings, or other related components.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 5 - Barren
Enumerated_Domain_Value_Definition:
Land comprised of soils, sand, or rocks where less than 10 percent of the area is vegetated. Barren lands are usually naturally occurring.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 6 - Forest
Enumerated_Domain_Value_Definition:
Tree-covered land where the tree cover density is greater than 10 percent. Note that cleared forest land (i.e., clear-cuts) is mapped according to current cover (e.g., mechanically disturbed or grassland/shrubland).
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 7 - Grassland/Shrubland
Enumerated_Domain_Value_Definition:
Land predominately covered with grasses, forbs, or shrubs. The vegetated cover must comprise at least 10 percent of the area.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 8 - Agriculture
Enumerated_Domain_Value_Definition:
Land in either a vegetated or an unvegetated state used for the production of food and fiber. This includes cultivated and uncultivated croplands, hay lands, pasture, orchards, vineyards, and confined livestock operations. Note that forest plantations are considered forests regardless of the use of the wood products.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 9 - Wetland
Enumerated_Domain_Value_Definition:
Land where water saturation is the determining factor in soil characteristics, vegetation types, and animal communities. Wetlands usually contain both water and vegetated cover.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 10 - Non-mechanically disturbed
Enumerated_Domain_Value_Definition:
Land in an altered and often unvegetated state that, due to disturbances by non-mechanical means, is in transition from one cover type to another. Non-mechanical disturbances are caused by fire, wind, floods, animals, and other similar phenomena.
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Enumerated_Domain:
Enumerated_Domain_Value: 11 - Ice and Snow
Enumerated_Domain_Value_Definition:
Land where the accumulation of snow and ice does not completely melt during the summer period (e.g., alpine glaciers and snowfields).
Enumerated_Domain_Value_Definition_Source: Trends land-use/land-cover class descriptions
Metadata_Reference_Information:
Metadata_Date: 20140519
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kristi L. Sayler
Contact_Organization: U.S. Geological Survey
Contact_Position: Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: USGS/EROS
Address: 47914 252nd Street
City: Sioux Falls
State_or_Province: SD
Postal_Code: 57198-0001
Country: USA
Contact_Voice_Telephone: 605-594-6058
Contact_Facsimile_Telephone: 605-594-6529
Contact_Electronic_Mail_Address: sayler@usgs.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
Metadata_Access_Constraints: None
Metadata_Use_Constraints: None
Metadata_Extensions:
Online_Linkage: <http://pubs.usgs.gov/ds/844>