Section 1	Identification Information
Originator	Tiger/Line 1995 - US side, Statistics Canada/1996 census subdivisions - Canadian side
Title	Census data for the Lake Superior Basin
Abstract	This data set consists mostly of polygons taken from Tiger/Line files and Statistics Canada to create a basin-wide census coverage. This data was clipped with a 50 km buffer of the Lake Superior Drainage basin, and then split into counties for the US side, and kept whole for the Canada side. The attributes contain much census information; specifically from the years 1990, 1991, and 1996. For a more detailed description, see 'entity and attribute overview.'
Purpose	A base data layer.
Time Period of Content Date	1995
Currentness Reference	Date of Tiger/Line data and Canada Census Subdivisions data
Progress	Complete
Maintenance and Update Frequency	As needed
Spatial Extent of Data	Lake Superior Basin and 50 km buffer, including parts of Minnesota, Michigan, Wisconsin, and Ontario, Canada
Bounding Coordinates	-97.293 -81.564 49.255 41.573
Place Keywords	Minnesota, Michigan, Wisconsin, and Ontario
Theme Keywords	Population, owned, rented
Theme Keyword Thesaurus	None
Access Constraints	None
Use Constraints	None
Contact Person Information	Mark White, Research Fellow Natural Resources Research Institute 5013 Miller Trunk Hwy Duluth, Minnesota 55811 Phone: (218)-720-2710 FAX: (218)-720-4328 E-mail: mwhite@sage.nrri.umn.edu
Browse Graphic File Name	none available
Browse Graphic File Description
Associated Data Sets
Section 2	Data Quality Information - - - - - - Go back to top
Attribute Accuracy	US side: Topological Properties The attribute accuracy of the TIGER/Line ® files is as precise as the source used during the creation or update of the Census TIGER ® data base. Accuracy statements on the Census TIGER ® data base are based on deductive estimates; no specific field tests for attribute accuracy have been conducted on the files. However, updates or corrections resulting from normal Census Bureau field operations are entered into the Census TIGER ® data base. In addition, quality checks are conducted to verify clerical transcription of data from source materials. Based on past experience, attribute codes match the source materials with less than a two-percent error. The feature network of complete chains (as represented by Record TypesÊ1 and 2) is complete for census purposes. Data users should be aware that on occasion they may not be able to trace a specific feature by name or by CFCC as a continuous line throughout the TIGER/Line ® files without making additional edits. For example, State Highway 32 may cross the entire county. The TIGER/Line ® files will contain com-plete chains in the file at the location of State Highway 32, but the complete chains may individually have one of a collection of local names such as S Elm Street, or Smallville Highway, with or without State Highway 32 as an alternate. The most frequent CFCC for a state highway is A21, but the complete chains at the location of State High-way 32 may have a variety of class codes such as A01, A41, or A21. Recent edits have reduced this problem, but not eliminated it. Boundaries and Geographic Entity Codes The Census Bureau collects and tabulates information for both legal and statistical entities. Record Types 1 and S identify the boundaries and codes for the legal entities reported to the Census Bureau to be legally in effect on January 1, 1995. Record Types 3 and A generally contain the final 1990 census tabulation geographic boundaries and codes for those entities. Most legal boundaries are based on the anno-tations made by local officials in response to the Census Bureau’s Boundary and Annexation Surveys. Census Statistical Area Committees (CSACs) generally define and delineate statistical entities following Census Bureau guidelines. However, there are several exceptions:  UAs are defined strictly by the Census Bureau based on technical considerations.  School districts are delineated by State Departments of Education.  Voting Districts (VTDs) are supplied by the designated liaison for the 1990 Redistricting Data Program. The USGS maintains the file that is published as FIPS 55. The Census Bureau uses the file for coding American Indian/Alaska Native Areas, county subdivisions, consolidated cities, places, and sub-MCDs. Cooper-atively in 1993, the Census Bureau and the USGS edited the FIPS 55 file to ensure alphabetical sorting and data consistency. As a result, several hundred changes were made to the FIPS 55 codes and related class codes. These corrections, plus codes for new entities, appear in Record Type C where one record shows the codes used in 1990, and one record shows the current FIPS 55 code/class code associated with each change. Other attribute data in the TIGER/Line ® files were gathered from many sources. The Census Bureau’s staff linked the attribute informa-tion to the spatial framework of features. Most procedures for gathering the needed attributes were clerical. The quality of these attributes was ensured by various tests conducted before, during, and after the time that the attribute information was entered into the Census TIGER ® data base. Tests included source material selection and evaluation checks, quality control checks on staff work, independent reviews by local and tribal leaders of maps produced from the Census TIGER ® data base, and staff reviews of computer-performed operations. Canada: None available
Logical Consistency	US side: Node-line-area relationships satisfy topological requirements. These requirements include the following:  Complete chains must begin and end at nodes.  Complete chains must connect to each other at nodes.  Complete chains do not extend through nodes.  Left and right polygons are defined for each complete chain element and are consistent for complete chains connecting at nodes.  Complete chains representing the limits of a file are free from gaps. The Census Bureau performed automated tests to ensure logical consis-tency and limits of file. Some polygons in the TIGER/Line ® files may be so small, the polygon internal point has been manually placed on a node that defines the polygon perimeter. These small polygons have been detected, and corrections will be incorporated in the Census TIGER ® data base in the future. The Census Bureau uses its internally developedGeographic Update System to enhance and modify spatial and attribute data in the Census TIGER ® data base. The Census TIGER ® data base has three generations of currency in geo-graphic areas. These are generally the previous census areas, current areas, and the next census areas. The boundaries of geographic areas are affected by the location, type, and number of areas. To prepare for the 2000 census, those features used only as boundaries in the 1980 census were deleted. The deletions lowered the overall count of complete chains and polygons. Standard geographic codes, such as FIPS codes for states, counties, munic-ipalities, and places, are used when encoding spatial entities. The Census Bureau performed spatial data tests for logical consistency of the codes during the compilation of the original Census TIGER ® data base files. Most of the codes themselves were provided to the Census Bureau by the USGS, the agency responsible for maintaining FIPS 55. Canada side: None available
Completeness	US side: The GBF/DIME-Files and the USGS’s DLG were the two main sources of spatial attribute data. Data for a given category contain attribute codes that reflect the information portrayed on the original source. The TIGER/Line ® files also use the Census Bureau’s internal coding scheme which in some cases parallels the FIPS codes. The feature network of complete chains is complete for census purposes. For the 1990 census, census enumer-ators identified new and previously unreported street features for the entire Nation during a series of decennial census operations. In some areas, local officials reviewed the census maps and identified new features and feature changes. Similar operations are planned for the 2000 census. The TIGER/ Line ® files contain limited point and area landmark data. The enumerator updates from the 1990 census did not stress landmark features. Computer file matching and automated updates from the Economic and Agriculture censuses added landmarks and key geographic locations (KGLs). As source material from the US Postal Service and local agencies is integrated into the Census TIGER ® data base, the number of landmarks and KGLs is expected to increase. Canada side: None available
Horizontal Positional Accuracy	US side: The Census Bureau’s mission to count and profile the Nation’s people and institutions does not require very high levels of posi-tional accuracy in its geographic products. Its files and maps are designed to show only the relative positions of elements. Coordinates in the TIGER/Line ® files have six implied decimal places. The positional accuracy of these coordinates is not as great as the six decimal places suggest. The positional accuracy varies with the source materials used, but at best meets the established National Map Accuracy standards (approximately + Ú – 167 feet) where 1:100,000- scale maps from the USGS are the source. The Census Bureau can not specify the accuracy of feature updates added by its field staff or of features derived from the GBF/DIME-Files or other map sources. Thus, the level of positional accuracy in the 1995 TIGER/Line ® files is not suitable for high-precision measurement applications such as engineering problems, property transfers, or other uses that might require highly accurate measurements of the earth’s surface. Despite the fact that TIGER/Line ® data positional accuracy is not as high as the coordinate values imply, the six-decimal place precision is useful when producing maps. This precision allows you to place features that are next to each other on the ground in the correct position, relative to each other, on the map without overlap. Canada side: The purpose of the 1996 Census FSA Digital Cartographic File is to support analyses of census data for FSAs. No attempt was made to compare the EA-based FSA boundaries to FSA maps that are available from other sources. For this product, the true position of an FSA boundary refers to the spatial distribution of census respondents reporting that FSA. The use of EAs for building blocks of FSAs approximates this true position. This section presents two quality indicators for the delineation : coverage and dominance. These indicators are useful to assess the extent to which the delineation portrayed on the 1996 Census FSA Digital Cartographic File accurately illustrates the true location of people reporting that FSA. A perfect delineation would be one where all people reporting a given FSA live within the boundaries created for that FSA and no one living within the boundaries reported another FSA. Coverage measures the extent to which people reporting a given FSA live within the boundaries delineated for that FSA. In this example, the EA based delineation of FSA #1 includes 23 of the 25 people reporting FSA1, a coverage of 92%. Dominance measures the extent to which people living within the EA based boundaries of a given FSA effectively reported that FSA. In this example, 23 of the 26 people living within the boundaries delineated for FSA #1 effectively reported that FSA, a dominance of 88%. The following tables give the frequency distribution of these two measures. In both cases, the distribution is heavily concentrated in the 90 to 100 % range Frequency distribution of the Coverage Quality Indicator Frequency distribution of the Dominance Quality Indicator Coverage (%) Number of FSAs % Dominance (%) Number of FSAs % no boundaries 29 2.0 no boundaries 29 2.0 0 - 20 2 0.1 0 - 20 9 0.6 20 - 40 3 0.2 20 - 40 12 0.8 40 - 60 21 1.4 40 - 60 14 1.0 60 - 80 48 3.3 60 - 80 45 3.0 80 - 90 96 6.6 80 - 90 93 6.3 90 - 100 1268 86.4 90 - 100 1265 86.2 Neither of these two measures gives a full appreciation of the positional accuracy of the delineation. For instance some boundaries may include all people reporting the FSA (100% coverage) but perhaps also a large population reporting another FSA (weak dominance). Similarly, an FSA may totally dominate its EA-based spatial representation (no other FSA reported), but several people reporting it may be missing from the delineation (under coverage). A Composite Quality Indicator was calculated to help users appreciate the overall positional accuracy of the boundaries included in this product. The following table shows the frequency distribution of that Composite Quality Indicator. It illustrates the downward impact on the measure of quality when both coverage and dominance are considered. The majority of FSAs (88% or 1,285) have an overall quality indicator greater than 80%. Frequency distribution of the Composite Quality Indicator Composite Indicator (%) Number of FSAs % Cumulative % 90 - 100 977 66.6 66.6 80 - 90 308 21.0 87.6 60 - 80 83 5.7 93.3 40 - 60 33 2.2 95.5 20 - 40 20 1.4 96.9 0 - 20 17 1.2 98.0 no boundaries 29 2.0 100 The Composite Quality Indicator for each FSA is summarized by A, B or C and is included as an attribute of the boundaries on the 1996 Census Forward Sortation Areas Digital Cartographic File. In total, boundaries are available for 1,438 FSAs. Letter Range of Composite Indicator A greater than 90% less than, or equal to 100% B greater than 80% less than, or equal to 90% C greater than 0% less than, or equal to 80%
Vertical Positional Accuracy	Not applicaple
Lineage	US side: Source codes that specify the original digital source of complete chains in the TIGER/Line ® files are listed in the Sources section of this chapter. These codes cover the source categories in the Census TIGER ® data base: initial source, pre-1990 computer operations, office operations, enumer-ator operations, local official updates, post-1990 census updates, and pre-2000 computer operations. The initial sources used to create the Census TIGER ® data base were the USGS 1:100,000-scale Digital Line Graph (DLG), USGS 1:24,000-scale quadrangles, the Census Bureau’s 1980 geographic base files (GBF/DIME-Files), and a variety of miscellaneous maps for selected areas outside the contiguous 48 states. The DLG coverage is extensive, albeit of variable currency, and comprises most of the rural, small city, and suburban area of the TIGER/Line ® files. GBF/DIME-File coverage areas were updated through 1987 with the manual translation of features from the most recent aerial photography available to the Census Bureau. In order to create a current geographic data base for the extraction of the 1995 TIGER/Line ® files, the Census Bureau used various internal and external procedures through 1995 to update and maintain the Census TIGER ® data base. While the Census Bureau has made a reasonable and systematic attempt to gather the most recent information available about the features that this file portrays, the Census Bureau cautions users that the files are no more complete than the source documents used in their compilation, the vintage of those source documents, and the translation of the information on those source documents. The Census Bureau added, to the Census TIGER ® data base, the enu-merator updates compiled during the 1988-1990 census operations. The updates came from map annotations made by enumerators as they attempted to locate living quarters by traversing every street feature in their assignment area. The Census Bureau digitized the enumerator updates directly into the Census TIGER ® data base with-out geodetic controls or the use of aerial photography to confirm the features’ existence or locational accuracy. The Census Bureau also made other corrections and updates to the map sheets supplied by local participants in various Census Bureau programs. Unconfirmed local updates originated from map reviews by local government officials or their liaisons. Maps were sent to the highest elected official of governmental units between 1990-1995 for use in various census programs, and some maps were returned with update annotations and corrections. The Census Bureau generally added the updates to the Census TIGER ® data base without extensive checks when the elected official approved the boundary or feature cor-rection. Changes made by local officials do not have geodetic control. Canada side: Sources The 1996 Census FSA Digital Cartographic File was derived using the 1996 Enumeration Areas Digital Boundary and Digital Cartographic Files, as well as the preliminary and final counts of households by enumeration area and postal code. The preliminary counts were those available immediately after the postal codes reported on census questionnaires were first data captured. These postal codes were subsequently processed through a series of edit operations that identified missing or invalid responses and replaced them with a valid response to produce the final counts. The 1996 Census population and dwelling counts for postal codes and forward sortation areas are published in Postal Code Counts (catalogue no 92F0086XCB), a CD-ROM product. Users should refer to the Data Quality section of the Postal Code Counts User's Guide for more information on the validation of postal codes. The creation of the 1996 Enumeration Areas Digital Cartographic and Digital Boundary File is described in details in section 3 of this reference guide. Method of derivation This section describes the methods used to assign a forward sortation area to each enumeration area in the country. The grouping of EAs to form FSA boundaries follows the same procedure described in section General Methodology. Approximately 36 % of the 46,924 populated enumeration areas reported a single FSA. This left over 30,000 enumeration areas for which a choice between two or more (up to 13) FSAs was necessary. Generally, the FSA reported by the largest number of census respondents was assigned to the EA (the FSA is said to dominate the EA). The automated rule described below was used to assign a single FSA to the EAs with no population and EAs with no dominant FSA (e.g. an EA may contain 100 households, 50 of which reported one FSA and 50 of which reported another FSA). The analyses of the resulting assignment resulted in marginal modifications to the automated process on a case by case basis. Dominance in surrounding EAs: There are 2,437 EAs which do not contain any population according to the 1996 Census. In these cases, a cluster of EAs was formed, consisting of the EA for which an assignment is required and adjacent EAs. The single FSA reported by the largest number of people in the cluster was assigned to the EA. This rule was also used for EAs with with no dominant FSA. Case by case assignment: Fifty-six FSAs reported by census respondents never dominated an EA or cluster of EAs. Twenty-seven were assigned an FSA based on a case by case analysis. This was done to provide a boundary for all FSAs for which census data are available, that is FSAs with at least 100 people. The remaining 29 FSAs reported in the Census are not depicted in the file. The analyses of the boundaries resulting from these assignments revealed that the strict application of the rule of dominance within the EA results in a large number of FSAs depicted in several parts (non-contiguous). This number was reduced by replacing the dominant FSA within selected EAs by the dominant FSA for the cluster made of adjacent EAs ( see Dominance in surrounding EAs). This modification was limited to 586 cases where the fragmentation involved small EAs or EAs reporting two or more FSAs in similar proportions (not a strong dominance). Note: Due to time constraint, preliminary delineation of FSA boundaries began immediately after data capture of the information. The impact of the edit and imputation stage on specific FSAs was taken into consideration and appropriate adjustments were made to create the final product. NRRI used a 50 km buffer of the Lake Superior Basin Boundary to clip out the relevant area.
Source Scale Denominator	100000
Section 3	Spatial Data Organization Information - - - - - - Go back to top
Native Data Set Environment	UNIX-ARC/INFO Ver. 7.1.2, Sun Solaris operating system
Geographic Reference for Tabular Data	None
Spatial Object Type	Vector
Vendor Specific Object Types	Polygon, area
Tiling Scheme	US side: counties, Canada: canada-wide
Section 4	Spatial Reference Information - - - - - - Go back to top
Horizontal Coordinate Scheme	Geographic (Lat. Long.)
Ellipsoid	GRS80
Horizontal Datum	NAD83
Horizontal Units	Meters
Distance Resolution
Altitude Datum	Not applicable
Depth Datum	Not applicable
Map Projection Name	Albers Equal Area
Map Projection Parameters	Standard Parallel: 29.5 Standard Parallel: 45.5 Longitude Of Central Meridian: -96 Latitude Of Projection Origin: 23 False Easting: 0 False Northing: 0
Other Coordinate System's Definition	Planar Coordinate Encoding Method: Coordinate Pair Abscissa Resolution: 1 Ordinate Resolution: 1 Semi-Major Axis: 6378206.4 Denominator of Flattening Ratio: 294.98
Section 5	Entity and Attribute Information - - - - - - Go back to top
Entity and Attribute Overview	US and Canada: CENID = Census unit identifier, Canda KM2 = area of unit in square kilometers POP91 = population of unit, 1990 usa, 1991 canada POP96 = population of unit, 1997(estimate) usa, 1996 canada (census) POPDKM90 = population density per square kilometer, 1990 usa, 1991 canada POPDKM96 = population density per square kilometer, 1997 usa, 1996 canada XDIF9196 = Percent difference in population 1991-1996 TOTHOUSES = Total houses per unit, HSKM2 = Houses per square kilometer OWNED N = Number of houses owned RENTED N = Number of houses rented XOWNOCC = Percent of housed owner occuppied CSDNAME = Cenus subdivision name (Canada) Census Subdivision Type BOR Borough C City CC Chartered Community CM County (Municipality) COM Community CT Canton CU Cantons Unis DM District Municipality HAM Hamlet ID Improvement District IGD Indian Government District LGD Local Government District LOT Township and Royalty M Municipalite MD Municipal District NH Northern Hamlet NT Northern Town NV Northern Village P Paroisse PAR Parish R Indian Reserve RC Rural Community RGM Regional Municipality RM Rural Municipality RV Resort Village S-E Indian Settlement SA Special Area SCM Subdivision of County Municipality SET Settlement SM Specialized Municipality SRD Subdivision of Regional District SUN Subdivision of Unorganized SV Summer Village T Town TI Terre Inuite TP Township TR Terres Reservees UNO Unorganized-Non organise V Ville VC Village Cri VK Village Naskapi VL Village VN Village Nordique CSDTYPE = Census Subdivision type (Canada) CNTY_FIPS = USA county fips code TRACT = USA census tract
Entity and Attribute Detailed Citation	None
Section 6	Distribution Information - - - - - - Go back to top
Publisher	Natural Resources Research Institute
Publication Date	Unpublished material
Contact Person Information	Gerald Sjerven, GIS Specialist Natural Resources Research Institute 5013 Miller Trunk Hwy Duluth, Minnesota 55811 Phone: (218)-720-4388 FAX: (218)-720-4328 E-mail: gsjerven@sage.nrri.umn.edu
Distributor's Data Set Identifier
Distribution Liability	No warranty expressed or implied is made regarding the accuracy 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. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The University of Minnesota shall not be held liable for improper or incorrect use of the data described and/or contained herein.
Transfer Format Name	ARC/Info export format
Transfer Format Version Number
Transfer Size
Ordering Instructions
Online Linkage	Click here to download data. (See Ordering Instructions above for details.) By clicking here, you agree to the notice in "Distribution Liability" above.
Section 7	Metadata Reference Information - - - - - - Go back to top
Metadata Date	08/25/1999
Contact Person Information	Joel Nelson, GIS Intern Natural Resource Research Institute 5013 Miller Trunk Highway Duluth, Minnesota 55811 Phone: (218)-720-4254 FAX: (218)-720-4328 E-mail: jnelson@sage.nrri.umn.edu
Metadata Standard Name	Minnesota Geographic Metadata Guidelines
Metadata Standard Version	Datalogr 2.01
Metadata Standard Online Linkage	http://www.lmic.state.mn.us/gc/stds/metadata.htm

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