Region 8
Serving Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming and 27 Tribal Nations
Metadata for R8_HUC
REGION 8 HYDROLOGIC UNITS AT 1:250K SCALE
Table of Contents
Text between this line and the next follows the hierarchy of data elements in the FGDC Content Standards for Digital Geospatial Metadata. Narratives written for earlier metadata of this data set sometimes did not match the FGDC sections. Where necessary, hypertext pointers were used to avoid rewriting the narrative.
Identification_Information:
Citation_Information:
Originator: BY PETE STEEVES OF USGS WRD, MA OFFICE DURING THE SUMMER OF 1992
Publication_Date: 1995
Title: GIRAS 1:250K AND 1:100K DATA CONVERTED INTO ARC-INFO FORMAT
Publication_Information
Publication_Place: Denver, Colorado
Publisher: US EPA REGION 8 TMS-ISP
Description:
Region 8 HYDROLOGIC UNITS AT 1:250K SCALE
Abstract:
The Geographic Information Retrieval and Analysis System (GIRAS)
was developed in the mid 70's to put into digital form a number
of data layers which were of interest to the USGS. One of these
data layers was the Hydrologic Units. The map is based on the
Hydrologic Unit Maps published by the U.S. Geological Survey
Office of Water Data Coordination, together with the list
descriptions and name of region, subregion, accounting units, and
cataloging unit. The hydrologic units are encoded with an eight-
digit number that indicates the hydrologic region (first two digits),
hydrologic subregion (second two digits), accounting unit (third two
digits), and cataloging unit (fourth two digits).
The data produced by GIRAS was originally done at a scale of 1:250K.
Some areas, notably major cities in the west, were recompiled at
a scale of 1:100K. In order to be able to use this in GIS, the
data was converted into ARC-INFO where it was edgematched and
neatline boundaries were dissolved.
Purpose:
This data set was compiled originally so that the NAWQA study units
could have an intermediate scale boundary within which they could clip
their other GIS data layers into. The data will most likely be
used for illustration purposes for the study units in NAWQA. With
some programming efforts it may be possible to automate this data
whereby one can select a hydrologic unit and recieve all units
that flow into it. Finally, the data may be used as a base whereby
study areas can define their specific basin boundaries.
Intended use of data:
See the above statement
Supplemental_Information:
Limitations_of_Data:
These data were digitized at a scale of 1:250,000 with some portions
of coverage at 1:100,000- and 1:2 million scale. Limitations of
the data strictly revolve around this scale input. Any intention
of using it with better scale data (i.e. 1:24k hydrography) should be
carefully scrutinized first.
Procedures:
The data was recieved as compressed giras tar files representing
either a 1:250k quad or a 1:100k quad. Each file was named after its
respective quadrangle. A coverage of 1:250k quadrangles was used
to divide the country up into four sections and get a list of names
for each section. Using GIRASARC2, an aml designed to create an arc
info coverage out of a GIRAS file and a corresponding neat line coverage,
it was quickly discovered that many of the quad names were to long
for the program (i.e. sault_saint_marie) and a generic naming system for
files and coverages was incorporated. In 1 of 10 cases, the name of
the quadrangle did not correspond with the name of the file. These
problems were traced down and corrected (after all four sections were
converted there were many files left over...these wound up being all
the 1:100k quads which did not have similar names to the 1:250k
files).
After the files for a given section were all converted into arcinfo
format, a loop aml was run which copied a coverage and its neatline
cover into temporary storage (there was not enough room in info to
deal with a large number of files in one directory), attached to
that directory, ran a build on the coverage to create a line file,
and went into arcedit. Once there, the outside polygon was selected
and deleted and the neatline coverage was copied in using get (in all
cases, the outline of the coverage quad never quite conformed to the
neatline which was why this step was needed) with intersectarcs on add.
Dangles were selected and extended 500 feet maximum. This took care of
all undershoots. Overshoots were taken care of by CLEANing the coverage
into a seperate directory using a dangle length of 500 and tolerance of 2.
Both the neatline and huc coverages were deleted in the temporary space,
and the aml looped to the next coverage.
Another aml was then run which added an item to the .aat called outer,
went into info, and reselected lpoly# = 1 or rpoly# = 1 in the .aat and
calculated outer to = 1. All coverages were checked for additional
dangles and then a MAPJOIN was run using NET as the feature option.
Finally, the MAPJOINed coverage was DISSOLVEd using the item HUC as
the dissolve item and NET as the feature option.
The resulting coverage was then QC'ed for node and label errors and
remaining neat line arc problems (i.e. long neat lines still in the
coverage). Many more problems arose in the western part of the country
than in the east. Bordering HUC code disagreements between quads caused
a number of cases in which neatlines did not dissolve. These were
corrected for the most part, however there are still several blatant
errors that need to be correced. After all sections were complete,
the same procedure was done for the 1:100k quads, these were mapjoined
with the 1:250k quads and dissolve was then used.
Reviews_Applied:
Peer review, 1/5/93, Doug Nebert, USGS-WRD, Reston:
Data were reviewed for attribute accuracy against a 1:2million base through
random audit of polygon features. Line attributes were verified by symbol-
ization on the screen. Regions were shaded in to verify correct polygon
values for HUC at the Hydrologic Region level. Documentation was updated.
Peer review, 10/18/93, Bill Battaglin, USGS-WRD, Lakewood, Co, memo to
Doug Nebert:
----------------------------------------------------------------------
"I have completed a review of the 1:250,000 scale hydrologic units coverage
(HUC) and found the digital data and metadata to be of high quality. I have
a few suggested improvements to the digital data and to the documentation.
Below is a summary of the methods I used to check feature accuracy in the
digital data base and the problems I found.
Digital Features:
The line work for the HUC coverage was checked against the line work from:
(1) the 1:2,000,000 HUC coverage by plotting both data sets out on one large
graphic (about 1:3,000,000). No major discrepancies were found except in
coastal areas where the 1:2,000,000 scale coverage had more detail than the
1:250,000 scale coverage.
(2) line work from 1:24,000 scale digitized drainage basins in Colorado.
The match was generally good with departures generally less than 2500 meters.
The biggest departures were in Colorado and were as large as 4000 meters.
(3) line work from the 1:2,000,000 scale rivers coverage for the USA by
plotting both data sets out on one large graphic (about 1:3,000,000). In
general the nesting of streams in HUC's was good and HUC boundaries inter-
sected steams at stream intersections. In some places (NW Utah),
the streams coverage does not match the HUC coverage that well, but this
could easily be because of the unusual nature of streams in these areas or
because of inaccuracies in the streams coverage.
(4) line work from 1:100,000 scale streams from Colorado. The nesting of
streams in HUC's was very good. Stream arc's for the most part did not
cross HUC arcs except at stream intersections. The error (distance from
intersection to HUC line) between HUC lines and stream intersection was
less than 500 meters at all intersections checked(about 25).
Problems with Line work:
(1) There was a very large number of very short arcs in the coverage (3211
Lt 1000 meters long and 1729 Lt. 100 meters long). Most of these arcs were
internal (did not border on outside polygon) and coded as 250k edges(3)
(almost 3000) but some were 250k (2) lines and one was a 2m dlg (4). Arcs
with lengths of less than 100 meters (maybe even less than 1000 meters) are
difficult to deal with when editing subsets of the coverage, and they also
add to the overall size of the database. I know many of these lines were
created in the process of edgematching the quads, but I think the informa-
tion content of these very short arcs is less valuable than the hassle and
overhead involved in keeping them in the coverage.
(2) The edit distance for the coverage was set to a very small value.
This may have been required for earlier processing, however, it makes
the finished coverage difficult to work with. I had to reset the edit
distance to a larger value when I wanted to select arcs in ARCEDIT
interactively. This, of course, will be one of the things users will
want to do with the new HUC coverage.
Polygon labels/attributes:
(1) Label point accuracy was checked by making a point cover of polygon
labels from the 1:2,000,000 HUC coverage and then doing an identify of
those points in the 1:250,000 scale HUC polygon. This procedure looked
for both new or missing polygons, and was also used to check attribute
values. I also dissolved both coverages by accounting unit and compared
the number and location of remaining polygons.
Problems with labels/attributes:
(1) I discovered a total of 649 places where the HUC codes from the label
point of the 1:2,000,000 coverage did not match the HUC code for the
1:250,000 HUC polygon that it fell within. In other places the polygons
seemed to be the same but the HUC codes were different. For example
HUC 18020111 in the 1:2,000,000 coverage is coded as HUC 18020023 in the
1:250,000 coverage. There were also internal polygon label differences
in Colorado (10090204 in 250k, 10180007 in 2m)
(2) The dissolved 1:2,000,000 coverage contained 350 accounting unit
polygons while the dissolved 1:250,000 HUC coverage only contained 177.
There were large differences in the way the Accounting unit polygons
looked in Wyoming.
Coverage Documentation:
The coverage documentation was reviewed both editorially and for overall
completeness. The documentation was editorially sound and did not need any
corrections.
Problems with the Documentation:
(1) The redefined items in the pat file were not defined in the data
dictionary portion of the documentation file.
(2) The complete reference to the source material for the data is not in the
documentation file."
Peer review, 11/10/93, Doug Nebert, USGS-WRD, Reston, memo to Paul Kapinos:
---------------------------------------------------------------------------
"As you are aware, we have several digital versions of the hydrologic unit
a 1:250,000-scale version derived from National Mapping Division Geographic
Information Retrieval and Analysis System (GIRAS) data as part of their land
use mapping program of the 1970's and early 1980's.
Peer review, 11/29/93, Paul Kapinos, USGS-WRD, memo to Doug Nebert:
-------------------------------------------------------------------
"The discrepancies in the hydrologic unit codes (and some boundaries)
in the State of California are due to the fact that the California
State Hydrologic Unit Map (HUM) was revised in 1978 but the 1:250,000-scale
digital data set was not. The events that most likely occurred can be
summarized as follows:
o The 1:500,000-scale HUM's were published by OWDC over a period of about
four years between 1974 and 1978.
o The National Mapping Division (NMD) overlaid the hydrologic unit
boundaries on their 1:250,000-scale land-use and land-cover map
series after each State HUM was completed, and later digitized these
boundaries and their respective codes.
o Once all the HUM's were printed (including the 1978 revisions of
South Dakota), the 1980 1:2.5 million-scale United States wall map was
published using the up-to-date (1978) boundaries and codes.
Based on the above summary, I would recommend using the boundaries
and codes from the 1:2.5 million-scale map and the 1:2,000,000 digital
data set. Please be aware that other hydrologic unit boundaries and/or
codes may have been revised when individual State HUM's were reprinted
by OWDC. I doubt if there has been any attempt to update any of the
digital data sets with these changes."
Other_Related_Data_Sets:
Any data set which has hydrologic unit codes as part of their data may be able
to use this data.
References_Cited:
USGS DIGITAL CARTOGRAPHIC DATA STANDARDS
LAND USE AND LAND COVER DIGITAL DATA
Notes:
U.S. Geological Survey and cooperating agencies until further review is
conducted and entered into this documentation file.
Other:
Time_Period_of_Content:
Time_Period_Information: Unknown
Currentness_Reference: publication date
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -117.2715
East_Bounding_Coordinate: -94.0395
North_Bounding_Coordinate: 48.9034
South_Bounding_Coordinate: 35.3139
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: HYDROLOGIC UNITS
Access_Constraints:
None
Use_Constraints:
None
Security_Information:
Security_Classification: UNCLASSIFIED
Native_Data_Set_Environment:
Arc/INFO
Data_Quality_Information:
Logical_Consistency_Report:
Polygon and chain-node topology present.
Completeness_Report:
See Supplemental_Information
Positional_Accuracy:
Horizontal_Positional_Accuracy: See Supplemental_Information Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: VARIABLE Vertical_Positional_Accuracy: See Supplemental_Information
Lineage:
See Supplemental_Information for overview.
Revisions_Applied:
Revision #1. 10/92 See above for all the details
Revision #3. 12/93. The following changes were made to a 1:250,000-scale
version derived from National Mapping Division's Geographic Information
Retrieval and Analysis System (GIRAS) data.
In Wyoming, a boundary was added in 100902 from the 1:2 million source.
Labels were corrected in these HUCs to reflect state updates, and where
necessary, to add new labels to the newly-drawn boundaries.
After the changes were made and saved in Arcedit, the 'build' and 'clean'
commands were executed, followed by 'labelerrors'. Three polygons had
duplicate labels and were corrected. The labels were centered in the
polygons by the 'centroidlabels' command. Verification of the coverage
was done by the 'describe' command.
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Albers Conical Equal Area
Alber_Conical_Equal_Area:
Standard_Parallel: 38
Standard_Parallel: 48
Longitude_of_Central_Meridian: -106
Latitude_of_Projection_Origin: 37
False_Easting: 0.00000
False_Northing: 0.00000
Geodetic_Model
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257
Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_label: R8_HUC.PAT
Entity_Type_Definition: HUC POLYGONS
Number_of_Attributes_in_Entity: 9
Attribute:
Attribute_Label: AREA
Attribute_Definition: Area of polygon in square coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Positive real numbers
Attribute:
Attribute_Label: PERIMETER
Attribute_Definition: Perimeter of polygon in coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Positive real numbers
Attribute:
Attribute_Label: R8_HUC#
Attribute_Definition: Internal feature number
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Sequential unique positive integer
Attribute:
Attribute_Label: R8_HUC-ID
Attribute_Definition: User-assigned feature number
Attribute_Definition_Source: User-defined
Attribute_Domain_Values: Integer
Attribute:
Attribute_Label: HUC
Attribute_Definition: HYDROLOGIC UNIT ID
Attribute_Definition_Source: GIRAS DATA
Attribute_Domain_Values: No restrictions
Attribute:
Attribute_Label: REGION
Attribute_Definition: Redefined item
Attribute_Definition_Source:
Attribute_Domain_Values: 2-character code
Attribute:
Attribute_Label: SUBREGION
Attribute_Definition: Redefined item
Attribute_Definition_Source:
Attribute_Domain_Values: 2-character code
Attribute:
Attribute_Label: ACCTUNIT
Attribute_Definition: Redefined item
Attribute_Definition_Source:
Attribute_Domain_Values: 2-character code
Attribute:
Attribute_Label: HYDROUNIT
Attribute_Definition: Redefined item
Attribute_Definition_Source:
Attribute_Domain_Values: 2-character code
Entity_Type:
Entity_Type_label: R8_HUC.AAT
Entity_Type_Definition: HYDROLOGIC UNIT LINEWORK
Number_of_Attributes_in_Entity: 8
Attribute:
Attribute_Label: FNODE#
Attribute_Definition: Internal number of from-node
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Sequential unique positive integer
Attribute:
Attribute_Label: TNODE#
Attribute_Definition: Internal number of to-node
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Sequential unique positive integer
Attribute:
Attribute_Label: LPOLY#
Attribute_Definition: Internal number of polygon to left of arc
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Sequential unique positive integer
Attribute:
Attribute_Label: RPOLY#
Attribute_Definition: Internal number of polygon to right of arc
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Sequential unique positive integer
Attribute:
Attribute_Label: LENGTH
Attribute_Definition: Length of arc in coverage units
Attribute_Definition_Source: Computed
Attribute_Domain_Values: Positive real numbers
Attribute:
Attribute_Label: SOURCE
Attribute_Definition: LINE CODING FOR UNIQUE CASES
Attribute_Definition_Source: GIRAS AND 1:2M DLG DATA
Attribute_Domain_Values: 1=100K 2=250K 3=250K EDGE 4=2MILLION DLG
Overview_Description:
Entity_and_Attribute_Overview:
For the time being there are two items of importance, one in the .AAT
and the other in the .PAT. The item in the .PAT is called HUC and is
explained in the abstract portion of this file. The item in the
.AAT is temporarily called SOURCE. It has four special codes for
the source linework. Code 1 stands for all arcs that were from 1:100,000
scale GIRAS files. Code 2 stands for 1:250,000-scale GIRAS files.
Code 3 is for 1:250K source but is also part of the neatline which may
be used to connect arcs that don't join cleanly between quads. Code
4 is for linework in the southern Central valley of California where
the GIRAS data were incorrect and the 1:2 million scale were replaced.
Entity_and_Attribute_Detail_Citation: See Entity_and_Attribute_Information
Distribution_Information:
Contact_Information
Contact_Organization_Primary
Contact_Organization: US EPA REGION 8 TMS-ISP
Contact_Person: Karl Hermann
Contact_Address
Address_Type: mailing and physical address
Address: 999 18th Street, Suite 300
City: Denver
State_or_Province: Colorado
Postal_Code: 80202-2466
Country: USA
Contact_Voice_Telephone: (303) 312-6628
Contact_Facsimile_Telephone: (303) 312-7554
Contact_Electronic_Mail_Address: hermann.karl@epa.gov
Hours_of_Service: Monday-Friday 8-4:30, Mountain Time
Distribution_Liability: Although these data have been processed
successfully on a computer system at the U.S. EPA, no warranty
expressed or implied is made by the EPA regarding the utility of the data
on any other system, nor shall the act of distribution constitute
any such warranty.
Standard_Order_Process: See contact information above.
Digital_Form:
Digital_Transfer_Information:
Format_Name: ARCEXPORT
Fees: None.
Available_Time_Period: Immediate.
Metadata_Reference_Information:
Metadata_Date: 20000801
Metadata_Contact
Contact_Information
Contact_Organization_Primary
Contact_Organization: US EPA REGION 8 TMS-ISP
Contact_Person: Marilynn Mueller
Contact_Address
Address_Type: mailing and physical address
Address: 999 18th Street, Suite 300
City: Denver
State_or_Province: Colorado
Postal_Code: 80202-2466
Country: USA
Contact_Voice_Telephone: (303) 312-6679
Contact_Facsimile_Telephone: (303) 312-7554
Contact_Electronic_Mail_Address: mueller.marilynn@epa.gov
Hours_of_Service: Monday-Friday 8-4:30, Mountain Time
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: 19940608
Metadata_Time_Convention: Local Time
Last modified: 01-05-14.14:39:35.Mon