Tualatin River Watershed Data Dictionary
Metadata for USGSLC92
Table of Contents
Identification_Information
Abstract
Purpose
Supplemental Information
Data_Quality_Information
Spatial_Data_Organization_Information
Entity_and_Attribute_Information
Detailed Description
Overview
Distribution_Information
Metadata_Reference_Section
Identification_Information
Citation_Information
Originator:
Publication_Date:
Title:
Description
Abstract
USGS Landcover (Classified 1992 TM Imagery - 9 classes)
Purpose
The Willamette Basin land cover map was created from Landsat
thematic mapper (TM) data collected in June and August of 1992
and 1993. Of the eight scenes used, only one was collected in
1993. For the initial work the five August scenes were mosaiced
together, with no smoothing or other kinds of spectral adjustment
to minimize seam lines between images. The basin boundary was
then used to eliminate data outside of the basin. Bands 3, 4,
and 5 of the TM data were used to create the mosaic. A color
print of the TM mosaic was created, assigning band 5 to red, band
4 to green, and band 3 to blue. The resulting image depicted
vegetation as green and non-vegetated or low density or dormant
areas took on a pinkish tone. Water was shown in dark blue to
black, and the snow caps of the peaks in the Cascades were
lighter shades of blue. Copies of the TM mosaic are available
by calling User Services at the EROS Data Center (605 594 6151)
and specifying order ID number E-1987-99cT in the PAO file.
Copies of the land cover map are also available by specifying
order ID E-1988-99cT. Color prints at various sizes and 9 inch
color positive transparencies can be ordered.
Supplemental_Information
Procedures_Used
The land cover map is currently available in an ARC GRID format.
The grid is in the UTM projection, and coordinates can be gotten
by using the ARC command DESCRIBE to display the location
parameters.
The file, wilcov.tar.Z, contains the grid image, tarred and compressed.
The compressed file is about 6 megabytes in size,uncompressed is about
16 megabytes.
Revisions
A small amount of manual editing of the cover map was done to
correct some obvious misclassifications. There were some deeply
shadowed forest areas in the southern end of the basin which were
misclassified as water. Using 1:250,000 topographic sheets as a
guide, obviously misclassified water bodies were converted to the
mature forest class. The wet areas of a few center pivot
irrigation systems along the Willamette River were misclassified
as native vegetation and were changed to the other irrigation
class.
Reviews_Applied_to_Data
Related_Spatial_and_Tabular_Data_Sets
References_Cited
Notes
Address questions by email to seevers@edcsnw44.cr.usgs.gov or by phone
to (605) 594-6010. Also, please forward any comments or suggestions you
may have regarding your experiences in using the map. We are particularly
interested in having examples of use of the data as a part of any analysis
or decision-making process where it has been involved.
Time_Period_of_Content
Currentness_Reference
Status
Progress: Unknown
Maintenance_and_Update_Frequency
Spatial_Domain
Bounding_Coordinates
West_Bounding_Coordinate: -123.44121567
East_Bounding_Coordinate: -122.62379636
North_Bounding_Coordinate: 45.81047805
South_Bounding_Coordinate: 45.28708383
Keywords
Theme
Theme_Keyword_Thesaurus: None
Theme_Keyword: TM imagery, landcover, USGS
Place
Place_Keyword_Thesaurus: None
Place_Keyword: Tualatin River Watershed
Stratum
Stratum_Keyword_Thesaurus: None
Stratum_Keyword:
Temporal
Temporal_Keyword_Thesaurus: None
Temporal_Keyword:
Access_Constraints
Use_Constraints
Rather than attempt to use the classification process to define
the urban areas, the decision was made to use an urban layer
provided by the Water Resources Division as the urban land cover
class. This layer was used as a mask to remove that portion of
the mosaic which represented the urban class. The remaining
digital data from bands 3, 4, and 5 of the August data were
processed to create an initial land cover map. The data were
clustered using an unsupervised clustering algorithm (CLUSTER) in
EDCs Land Analysis System (LAS) software package. The fifty
clusters from this processing were then assigned to land cover
categories through the following procedure. Each cluster was
displayed individually, and by visually relating the pixel
locations to features in the mosaic and accompanying ground
information, the cluster was defined to be associated with a
specified land cover class. Each cluster, in the majority of
cases, represented two or more cover classes. To resolve the
conflicting cover class depictions, a modeling scheme using
ancillary data was devised to define the cover class based on the
relationship of the cluster pixels to the ancillary data at that
pixel location. A set of decision rules was defined for each
cluster based on the cover classes indicated to be in conflict
and the relationship of the cover classes to the ancillary data
layers. A simple example would be a cluster which defined both a
forest type and an irrigated crop. Elevation would be a likely
factor to assign that pixel to the appropriate cover class; high
elevation indicating the forest type, low elevation indicating an
irrigated crop. Slope also could be a decision factor; nearly
level land being required for irrigation, forests growing on
steeper terrain. The ancillary data layers used in the modeling
scheme were digital elevation models (DEM), slope derived from
the DEMs, and STATSGO soils data.
The land cover map created from the modeling process did not
appear to define the agricultural classes as well as expected,
and it was desirable to have more agricultural classes if
possible. It was decided to acquire spring data to take
advantage of the contrast in vegetative cover of the agricultural
fields between the spring and fall. Three scenes covering the
agricultural portion of the basin, acquired in June of 1992, were
available. All three scenes were acquired the same day
eliminating any problems associated with differences due to
different scene dates. In order to focus on the agricultural
portion of the basin, a mask was created from the initial land
cover map which allowed only the data associated with the land
cover classes identified as agricultural to be extracted from the
two TM data sets. These two extracted data sets were separately
processed using the CLUSTER algorithm and 25 clusters were
specified. Each clustered data set was aggregated to five cover
classes using the features of the TM images and associated ground
data. These aggregated data sets were then modeled together
using the association of the classes with their acquisition date
to the final cover class. The resulting land cover image had
four land cover classes, which were concatenated back into the
initial land cover map.
Data_Set_Credit
Security_Information
Security_Classification_System: None
Security_Classification: UNCLASSIFIED
Security_Handling_Description: None
Native_Data_Set_Environment: Windows_NT Windows_NT, ARC/INFO version 7.1.1
Cross_Reference
Originator: Unknown
Publication_Date:
Publication_Time:
Title:
Edition:
Geospatial_Data_Presentation_Form:
Series_Information
Series_Name:
Issue_Identification:
Publication_Information
Publication_Place:
Publisher:
Other_Citation_Details:
Online_Linkage:
Larger_Work_Citation:
Data_Quality_Information
Attribute_Accuracy
Attribute_Accuracy_Report: See Entity_Attribute_Information
Quantitative_Attribute_Accuracy_Assessment
Attribute_Accuracy_Value: See Explanation
Attribute_Accuracy_Explanation:
Attribute accuracy is described, where present, with each
attribute defined in the Entity and Attribute Section.
Logical_Consistency_Report: Not applicable for raster data.
Completeness_Report
Positional_Accuracy
Horizontal_Positional_Accuracy
Horizontal_Positional_Accuracy_Report:
Vertical_Positional_Accuracy
Vertical_Positional_Accuracy_Report:
Lineage: See Supplemental_Information for overview.
Process_Steps
Process_Step
Process_Description: JON PROJECT GRID WIL_TB USGSLC92 /S1/UTIL/PROJECT/UTM10-SP
Source_Used_Citation_Abbreviation:None
Process_Date: 19980310
Process_Time: 1909
Source_Produced_Citation_Abbreviation: None
Process_Step
Process_Description: KEITH DOCUMENT USGSLC92 CREATE KEITH
Source_Used_Citation_Abbreviation:None
Process_Date: 19980923
Process_Time: 1018
Source_Produced_Citation_Abbreviation: None
Cloud_Cover
Spatial_Data_Organization_Information
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Grid Cell
Row_Count: 1819
Column_Count: 2008
Spatial_Reference_Information
Horizontal_Coordinate_System_Definition
Planar
Grid_Coordinate_System
Grid_Coordinate_System_Name: State_Plane_Coordinate_System
Zone_Number: 5076
Planar_Distance_Units: FEET
Geodetic Model
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: GRS1980
Entity_and_Attribute_Information
Detailed_Description
Entity_Type
Entity_Type_Label: USGSLC92.VAT
Entity_Type_Definition: Value Attribute Table
Entity_Type_Definition_Source: Generated
Attribute:
Attribute_Label: -
Attribute_Definition: Value Attribute Table
Attribute_Definition_Source: Generated
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Internal feature number for GRIDs
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Integer
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: COUNT
Attribute_Definition: Number of GRID cells of a VALUE
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Integer
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Entity_Type
Entity_Type_Label: USGSLC92.STA
Entity_Type_Definition: Statistics table
Entity_Type_Definition_Source: GRID
Attribute:
Attribute_Label: -
Attribute_Definition: Statistics table
Attribute_Definition_Source: GRID
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: -
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: MIN
Attribute_Definition: Minimum GRID cell VALUE
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Real number
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: MAX
Attribute_Definition: Maximum GRID cell VALUE
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Real number
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: MEAN
Attribute_Definition: Mean GRID cell VALUE
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Real number
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Attribute:
Attribute_Label: STDV
Attribute_Definition: Standard Deviation of GRID cell VALUEs
Attribute_Definition_Source: Computed
Attribute_Domain_Values
Enumerated_Domain
Enumerated_Domain_Value: Positive real number
Enumerated_Domain_Value_Definition
Enumerated_Domain_Value_Definition_Source:
Overview_Description
Entity_and_Attribute_Overview
The final land cover map had a total of nine land cover
categories. They were;
1. Urban
2. Water
3. Mature Forest
4. Regrowth Forest
5. Non-forest Upland
6. Native Vegetation, Valley Floor
7. Irrigated Crops
8. Grass Fields, Small Grains
9. Perennial Snow
The categories can be further defined as follows;
Urban - Areas of urban development as defined by the WRD
urban mask , which was a combination of USGS GIRAS
data and 1990 census data. These data represent a
population density of 1000 or more persons per square
mile.
Water - Open water defined by spectral classification.
Streams may show intermittent open water due to their
width in relation to the spatial resolution of the
satellite data.
Mature forest - This category represents the forested areas
which had the darkest shades of green in the mosaic.
Regrowth forest - This category represents the remaining
shades of green associated with forested areas in the
mosaic. It was the analysts call as to the cluster
assignment between this category and the mature
forest. There seemed to be logical combinations of
clusters which defined visually similar units within
the forested areas.
Non-forested upland - This category represents those areas
which did not give a green vegetation signature, and
was separated from the same signature on the valley
floor by elevation and slope differences. This
category includes recent clearcuts, open grassland, non-
forested alpine areas, and barren areas.
Native vegetation, valley floor- This category represents the
vegetated areas of the valley floor which did not
appear to be associated with agricultural activities
and gave a vegetated signature for both dates of data,
suggesting a natural source of water all during the
growing season. This category would include wetlands
and riparian vegetation associated with streams.
Irrigated crops - This category represents the irrigated crops as
defined by the vegetative patterns of the June and August data.
The basic assumption for irrigated crops was that fields planted
to crops requiring irrigation would be non-vegetated in
the June image and vegetated in the August image.
Grass fields, small grains - This category primarily represents the
grass seed producing fields of the valley floor. Also
included would be the hay fields, pastures, and small grains
of the valley.
Perennial snow - This category represents the unmelted snow of
the peaks of the Cascade Range as found in the August
data.
Consistency in identification of land cover was investigated by
comparison of available data sets with the land cover map. Following
are two initial comparisons.
Land cover, percent of basin
Cover category 1988 TM, BLM 1992 TM, NAWQA
water .89 .85
forested 63.32 60.19
non forested 35.78 38.96
Land cover, acres by county
Cover category 1992 Ag Census 1992 TM, NAWQA
Marion County
total cropland 242,561 248,322
Linn County
total cropland 297,200 297,675
Entity_and_Attribute_Detail_Citation: Not Available
Distribution_Information
Metadata_Reference_Section
Metadata_Date: 19980923
Metadata_Contact:
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: 19940608
Metadata_Time_Convention: Local Time
Metadata_Security_Information:
Metadata_Security_Classification_System: None
Metadata_Security_Classification: UNCLASSIFIED
Metadata_Security_Handling_Description: None
Last modified: 98-09-23.10:18:59.Wed
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