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1:100,000-scale Hydrography for Wyoming (Enhanced DLGs)

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Wyoming Gap Analysis
Publication_Date: 1996
Title: 1:100,000-scale Hydrography for Wyoming (enhanced DLGs)
Geospatial_Data_Presentation_Form: map
Publication_Information:
Publication_Place: Laramie, Wyoming
Publisher: Spatial Data and Visualization Center
Online_Linkage: <URL:http://www.sdvc.uwyo.edu/24k/hydro100.html>  
Description:
Abstract:
Hydrographic features for Wyoming at 1:100,000-scale, including perennial and intermittent designations and Strahler stream order attributes for streams. Does not include man-made ditches, canals and aqueducts. The data was originally produced by USGS, a Digital Line Graph (DLG) product, though this product was enhanced (edgematched, some linework and attributes corrected, stream order attribute added).

A subset of this dataset is also available for distribution, including only major streams (order 4 to 7) and major lakes and reservoirs. In order to reduce the size of this subset, the line segments were dissolved to remove unncessary segments.

Both datasets are available in Arc export file and shapefile format for download (see Onlink_Linkage)

Statewide and tiled data: there is one export file, which when imported into ARC/INFO, will contain one coverage with both polygon (lakes, reservoirs) and line (streams) topology and two feature attribute files (.PAT and .AAT) along with three additional attribute files containing descriptive information. In shapefile format, there will be two shapefiles (polygons and lines separated), with all attribute files in Dbase format.

Purpose:
The purpose of this data layer was to provide a base layer of water features at a statewide level for riparian/aquatic species distribution modeling for the Wyoming Gap Analysis project. However the data may also be used for a variety of other natural resources management/biological studies at the appropriate scale.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: unknown
Currentness_Reference: publication date of the source data, USGS DLGs  
Status:
Progress: complete
Maintenance_and_Update_Frequency: unknown, as needed

Spatial_Domain:

Bounding_Coordinates:
West_Bounding_Coordinate: -111.36554566
East_Bounding_Coordinate: -103.78380412
North_Bounding_Coordinate: 44.99390988
South_Bounding_Coordinate: 40.94479444
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: hydrography
Theme_Keyword: streams
Theme_Keyword: lakes
Theme_Keyword: water features
Theme_Keyword: stream order
Theme_Keyword: digital line graphs
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: Wyoming  
Access_Constraints: none
Use_Constraints:
Wyoming only. This data should never be used a scale larger than 1:100,000. The data is only as accurate as the source maps it was produced from, and use is dependent on the date of the sources and quality at which they were produced.  
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Data Manager
Contact_Organization: Spatial Data and Visualization Center
Contact_Address:
Address_Type: mailing address
Address: Box 4008 University Station
City: Laramie
State_or_Province: Wyoming
Postal_Code: 82071
Country: USA
Contact_Voice_Telephone: 307-766-2751
Contact_Electronic_Mail_Address: n/a
Hours_of_Service: 8:00 - 5:00 MST  
Browse_Graphic:
Browse_Graphic_File_Name: <URL:http://www.sdvc.uwyo.edu/images/hydro.gif>hydro.gif
Browse_Graphic_File_Description: example of perennial and intermittent hydrography
Browse_Graphic_File_Type: gif  
Data_Set_Credit:
United States Geologic Survey National Mapping Program, data source. Edgematching, corrections, ordering: Margo Berendsen, Tom Kohley - Wyoming Gap Analysis project. 
Native_Data_Set_Environment:
The data was created in and is stored in Arc/Info 7.0.4 software for Unix operating system. This dataset has both line (stream network) and polygon (lakes/reservoirs) topology. The dataset is served from the SDVC clearinghouse both in an entire statewide dataset and also tiled by 1:100,000 quadrangles, in Arc Export (e00) format and ArcView shapefile format.

Statewide and tiled data: there is one export file, which when imported into ARC/INFO, will contain one coverage with both polygon (lakes, reservoirs) and line (streams) topology and two feature attribute files (.PAT and .AAT) along with three additional attribute files containing descriptive information. In shapefile format, there will be two shapefiles (polygons and lines separated), with all attribute files in Dbase format.  

Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
This product is directly derived from the USGS DLGs, which according to the National Mapping Program do not currently carry quantified accuracy statements. However, procedures used by the NMP to validate the attribute accuracy involve computerized checking of attribute codes against a table of valid codes to endure that each attribute in a file is valid for the category. A manual process involving proof plots is used to verify correct application of codes.

The additional attribute added by Wyoming Gap Analysis, stream order, automatic generation by a ordering program. The coding was checked by displaying each order as a different color on screen, and special attention was paid to braided streams or other complicated areas of stream connection. The Strahler order attributes are correct only so far as the connectivity and completeness of the hydrographic network is represented due to generalizations at the 1:100,000-scale. Obviously, there will be differentiation in order at the larger 1:24,000-scale because of the more accurate representations of streams at that scale.

Attributes were also checked by visual color displays for intermittent and perennial attributes, as well as natural vs. man-made (all ditches, canals and aqueducts were removed). One section of Wyoming should be noted in particular for incorrect attributing which was corrected by Wyoming Gap Analysis: streams in Weston county, particularly the Lance Creek 1:100,000 quadrangle, were incorrectly labeled as perennial when, according to USGS 1:24,000-scale topographic maps, they were actually intermittent streams. Some linear features were corrected where they were man-made ditches/canals but incorrectly labeled as natural streams (primarily in the Pinedale quadrangle).

Approximately 12% of the 1,792 1:24,000-scale topographic maps for Wyoming were used to verify the 1:100,000-scale DLGS, however these quads were not statistically selected for verification but rather were selected to check areas that had already been identified as "problem areas".  

Quantitative_Attribute_Accuracy_Assessment:
Attribute_Accuracy_Value: unknown
Attribute_Accuracy_Explanation: none  
Logical_Consistency_Report:
There are no unclosed polygons, intersections without nodes, or polygons without labels or with more than one label. Arc/Info's topological checking program CLEAN was used to correct intersections without nodes, identify unclosed polygons and remove duplicate lines with the same beginning and ending nodes. Checks were not made for possible errors such as sliver polygons or duplicate lines missed by CLEAN, though if any such errors exist they are likely to be minor due to the topological tests performed on the raw DLG data by the USGS NMP.

Completeness_Report:

Some attributes may have a zero value because of the hierarchical nature of the DLG MAJOR and MINOR attributes (see the USGS National Mapping Program Digital Line Graphs Data Users Guide 2 for more details). The attribute added by Wyoming Gap Analysis, stream order, is complete for all linework (Arc/Info arc attribute table), line features being labeled as zero corresponding to water features which are not ordered, eg. lakes, ponds and reservoirs.

It should be noted that Wyoming Gap Analysis identified the two Yellowstone National Park quadrangles in the northwestern corner of the state to be mapped in less detail than surrounding quadrangles, (not just in the DLG product, but also on the original USGS 1:100,000-scale paper topological maps). Apparently different decision rules were applied by the NMP in translating hydrography from the 1:24,000-scale down to the 1:100,000-scale for this region of the state, and the data for these two quads should be considered as incomplete in comparison to the level of detail mapped for adjacent areas.  

Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The USGS NMP identifies these procedures used to qualify the positional accuracy of their DLG products: the data are either manually digitized using equipment with a resolution of 0.001 inch and an absolute accuracy of from 0.003 to 0.005 inch, or are scanned on an automatic device with a resolution of 30 points per millimeter, or 0.0013 inch. The positional accuracy of the data and complete- ness of the file are checked by visually comparing proof plots with the original stable-base source material. These proof plots are generated using automated drafting machines with a resolution of 0.001 inch and an absolute accuracy of from 0.003 to 0.005 inch.

Wyoming Gap Analysis converted raw DLG data into Arc/Info format with a 2 meter fuzzy tolerance (minimum distance between coordinates). Wyoming Gap Analysis also performed manual edge-matching along boundaries of 1:100,000-scale quadrangles of the source DLG data in Arc/Info, any positional offsets less than or equal to 200 meters being snapped together by splitting the distance between the two arcs. Other editing performed by Wyoming Gap Analysis which may or may not have an effect on the positional accuracy included adding or moving arc vertices and adding or lengthening arcs to join existing features in the edge-matching process. Grain tolerance used in adding/editing arc vertices was < 50m.

Approximately 12% of the 1,792 1:24,000-scale topographic maps for Wyoming were used to verify the 1:100,000-scale DLGS, however these quads were not statistically selected for verification but rather were selected to check areas that had already been identified as "problem areas", areas where its was not possible to determine how to connect streams along quadrangle edges by referring to the 1:100,000-scale maps alone.  

Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Title: Digital Line Graphs for Hydrography
Originator: U.S. Geological Survey, National Mapping Program
Publication_Date: 1994
Type_of_Source_Media: digital map
Source_Scale_Denominator: 100000
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: unknown
Source_Currentness_Reference: unknown, based on source paper maps
Source_Citation_Abbreviation: DLG
Source_Contribution: base data source
Process_Step:
Process_Description:
Raw DLG data (optional format) for Wyoming was converted to Arc/Info format 1:62,000-scale quads with a 2 meter coordinate resolution (fuzzy tolerance). These quadrangles were then tiled together into 1:100,000-scale quadrangles. During the process of tiling the 1:100,000-scale quadrangles into a statewide coverage, checking was done for proper feature alignment along the edges of the quads (edgematching). Streams or other hydrographic features with a positional offset (edge mismatch) of less than or equal to 200 m were snapped together by splitting the difference between them. In certain areas, it was necessary to refer to USGS 1:24,000-scale topographic maps to correctly determine the method of joining arcs. Editing changes included snapping endpoints of arcs together, adding or moving arc vertices, and adding new arcs to join or lengthen existing features. All arc features representing canals, ditches, or other man-made features were removed. Label errors which were identified by visual comparisons with paper maps were corrected.
Process_Date: 199501
Source_Used_Citation_Abbreviation: DLG
Process_Step:
Process_Description:
Following edgematching and other corrections to the original DLG data, all natural linear features were ordered, by major drainage (the state wide data was divided into 7 different drainages: North Platte, Belle Fourche, Crow, Wind River/Bighorn, Snake, Bear, Yellowstone) using the Strahler ordering method. The direction of flow of natural hydrographic features was adjusted using the Arc/Info TRACE command to best approximate the direction of flow in the drainage and its basins. A Strahler-ordering fortran program developed by USGS hydrologist, K. Lanfear, was applied to assign stream orders based on directional flow within the drainage. In cases of wide rivers represented by shorelines (instead of a stream centerline), braided rivers or stream networks interconnected circularly, the ordering had to rectified by interactive checking and editing. Wetlands, lakes, ponds and terminal reservoirs are not ordered. Streams flowing into Wyoming from other states (North Platte and Bear River drainages) were ordered based on visual inspection of source streams on 1:100,000-scale USGS maps of adjacent states (Colorado and Utah). Following the ordering and checking process, the individual drainages were appended back into a statewide coverage.
Process_Date: 199502
Source_Used_Citation_Abbreviation: DLG

Spatial_Data_Organization_Information: 

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Point
Point_and_Vector_Object_Count: 9402
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: String
Point_and_Vector_Object_Count: 93623
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains
Point_and_Vector_Object_Count: 12131

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: .001
Longitude_Resolution: .001
Geographic_Coordinate_Units: Decimal Degrees
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: GRS1980
Semi-major_Axis: 6378137

Denominator_of_Flattening_Ratio: 298.257

Entity_and_Attribute_Information:

Overview_Description:
Entity_and_Attribute_Overview:
This dataset is in the format of one ARC/INFO coverage with both line and polygon topology, for stream features lakes/reservoirs. The dataset is also provided as two shapefiles, one for streams and a separate one for polygon featuers. There are 9 attributes associated with each line (stream) feature, and 8 for each polygon.

The first 8 attributes, MAJOR and MINOR codes 1-4, are part of the standard hierarchical coding scheme of the DLGs. The MAJOR attributes 1 and 2 are coded as 50 or 0, 50 representing a hydrographic feature digitized by the USGS, and 0 representing a hydrographic feature digitized by Wyoming Gap Analysis project.

The MINOR attributes 1,2,3 have a numeric code for each feature, for example 412 is the code for stream and 200 is the code for shoreline. Most features only have associated codes at the highest level, MINOR1. (MINOR 2 and 3 identify other codes; for instance a stream may also be labeled as intermittent in MINOR2 and labeled as a boundary for a wetland in MINOR3).

The most common MINOR2 attribute is 610, identifying intermittent features.

The last two attributes, ORDER and RIPARIAN, were added by Wyoming Gap. ORDER identifies the Strahler order for the stream, 1-7. Polygon labels do not have an ORDER attribute. Arcs identified as shorelines, wetland boundaries or terminal reservoir boundaries are labeled as ORDER = 0. A look-up table for displaying order in ArcPlot is included with the dataset, HYDRO.ORDER. The RIPARIAN attribute was added to identify intermittent streams which might possibly have riparian vegetation associated with them; this attribute was added only for the purposes of riparian modeling in Gap Analysis and has no other functional use within the dataset.

Definitions of Minor1,2 and 3 codes are listed here and are also included in two INFO tables accompanying the Arc/Info coverage: HYDRO.LINE and HYDRO.POLY. These files can also serve as display look-up tables for Arcplot, since they include symbol colors for the COLOR lineset.

For ArcView users, these INFO files are also available as dBASE files, hy_line.dbf, hy_poly.dbf and hy_order.dbf.

Definitions for line attribute values (.AAT):  

200=Shoreline
412=stream
605=right bank
606=left bank
420=wash
103=glacier boundary
201=man-made shore
406=dam or weir
202=closure line
203=indefinite shore (identifies high-water mark)
204=apparent limit
400=rapids
401=falls
610=intermittent (all else assumed perennial)
Definitions for polygon attribute values (.PAT):

101=reservoir
103=glacier
105=inundation area
108=submerged area (due to dam-building)
109=sewage pond
110=tailings pond
111=marsh/wetland,
402=gravel pit
412=wide river (represented by left and right bank)
420=emphemeral wash
421=lake or pond.

Entity_and_Attribute_Detail_Citation: n/a
Detailed_Description:
Entity_Type:
Entity_Type_Label: HYDRODLG.AAT
Entity_Type_Definition: contains codes for line hydrographic features
Entity_Type_Definition_Source: n/a
Attribute:
Attribute_Label: MAJOR 1-4
Attribute_Definition: Identifies DLG lines for hydrography
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0
Range_Domain_Maximum: 50
Attribute:
Attribute_Label: MINOR 1-4
Attribute_Definition: Identifies different line hydrographic codes
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Arc (line) feature codes
Codeset_Source:
USGS DLG data user guide, also see attached file, HYDRODLG.LINE
Attribute:
Attribute_Label: ORDER
Attribute_Definition: Identifies Strahler stream order
Attribute_Definition_Source: Wyoming Gap Analysis Project
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0
Range_Domain_Maximum: 7
Detailed_Description:
Entity_Type:
Entity_Type_Label: HYDRODLG.PAT
Entity_Type_Definition: contains code for polygon hydrographic features
Entity_Type_Definition_Source: n/a
Attribute:
Attribute_Label: MAJOR 1-4
Attribute_Definition: Identifies DLG lines for hydrography
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0
Range_Domain_Maximum: 50
Attribute:
Attribute_Label: MINOR 1-4
Attribute_Definition: Identifies different hydrographic polygon codes
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Polygon feature codes
Codeset_Source:
USGS DLG data user guide, also see attached file, HYDRODLG.POLY
Detailed_Description:
Entity_Type:
Entity_Type_Label: HYDRODLG.LINE
Entity_Type_Definition: contains definitions of arc hydrographic feature codes
Entity_Type_Definition_Source: n/a
Attribute:
Attribute_Label: MINOR1
Attribute_Definition: Code associated with hydrographic features
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Line feature codes
Codeset_Source: This file, HYDRODLG.LINE
Attribute:
Attribute_Label: TYPE
Attribute_Definition: definition of feature code
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Line feature descriptions
Codeset_Source: This file, HYDRODLG.LINE
Attribute:
Attribute_Label: SYMBOL
Attribute_Definition: Arc/Info color symbol for display
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Arc/Info COLOR lineset
Codeset_Source: Arc/Info software
Attribute:
Attribute_Label: FREQUENCY
Attribute_Definition: number of features of a given value
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 2
Range_Domain_Maximum: 15127
Detailed_Description:
Entity_Type:
Entity_Type_Label: HYDRODLG.POLY
Entity_Type_Definition: contains definitions for polygon hydrographic feature codes
Entity_Type_Definition_Source: n/a
Attribute:
Attribute_Label: MINOR1
Attribute_Definition: Code associated with hydrographic features
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Polygon feature codes
Codeset_Source: This file, HYDRODLG.POLY
Attribute:
Attribute_Label: TYPE
Attribute_Definition: definition of feature code
Attribute_Definition_Source: USGS DLG data user guide
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Polygon feature descriptions
Codeset_Source: This file, HYDRODLG.POLY
Attribute:
Attribute_Label: SYMBOL
Attribute_Definition: Arc/Info color symbol for display
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Arc/Info COLOR lineset
Codeset_Source: Arc/Info software
Attribute:
Attribute_Label: FREQUENCY
Attribute_Definition: number of features of a given value
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 8172
Detailed_Description:
Entity_Type:
Entity_Type_Label: HYDRODLG.ORDER
Entity_Type_Definition: contains Strahler order frequencies/symbol colors
Entity_Type_Definition_Source: n/a
Attribute:
Attribute_Label: ORDER
Attribute_Definition: Code used to define stream order
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Stream order codes
Codeset_Source: this file, HYDRODLG.ORDER
Attribute:
Attribute_Label: SYMBOL
Attribute_Definition: Arc/Info color symbol for display
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Codeset_Domain:
Codeset_Name: Arc/Info COLOR lineset
Codeset_Source: Arc/Info software
Attribute:
Attribute_Label: FREQUENCY
Attribute_Definition: number of features of a given value
Attribute_Definition_Source: n/a
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1684
Range_Domain_Maximum: 41557
 
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Data Manager
Contact_Organization: Spatial Data and Visualization Center
Contact_Address:
Address_Type: mailing address
Address: Box 4008 University Station
City: Laramie
State_or_Province: Wyoming
Country: USA
Postal_Code: 82071
Contact_Voice_Telephone: 307-766-2751
Contact_Electronic_Mail_Address: n/a
Distribution_Liability:
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 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 identifying hydrographic feature locations in Wyoming. makes no claims for the data's suitability for other purposes.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ARCE (Arc/Info export)
Format_Version_Number: 7.0.4
Format_Version_Date: 1995
File_Decompression_Technique: Export file was created using defaults, no compression
Transfer_Size: 70.9
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: ftp.sdvc.uwyo.edu or <http://www.sdvc.uwyo.edu/clearinghouse>
Access_Instructions: <http://www.sdvc.uwyo.edu/clearinghouse/howto.html>
Online_Computer_and_Operating_System:
Both the ftp and WWW server which this data is available from is a Silicon Graphics Challenge server, running the IRIX 6.2 UNIX operating system.
Fees:

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

 Metadata_Reference_Information:

Metadata_Date: 199805
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Margo Berendsen
Contact_Address:
Address_Type: mailing address
Address: Box 4008 University Station
City: Laramie
State_or_Province: Wyoming
Postal_Code: 82071
Country: USA
Contact_Voice_Telephone: 307-766-2751
Contact_Electronic_Mail_Address: meh@uwyo.edu
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998 

Generated by mp version 2.4.13 on Mon Sep 18 14:39:47 2000